How we can say that conjugation is sexual reproduction in
Reproduction in Bacteria - Asexual and Sexual Reproduction
Bacterial Conjugation: Definition & Protocol - Video
conjugation bacterial reproduction
conjugation bacterial reproduction - win
Bacterial Conjugation = Sexual reproduction according to UEarth????
I got a Freestanding question that basically asked: Which of these is a way to classify an organism as a eukaryote? A. It is able to reproduce sexually B. It has a mechanism for intron splicing The answer was B. However, I really don't agree with this answer because the explanation states that bacteria reproduce sexually via conjugation... which I'm pretty sure doesn't meet the criteria for sexual reproduction. Additionally, Archaea have introns, so you can't choose B. Likewise, I chose A. Anyone have any help? Side note: Wikepedia on bacterial conjugation "Classical E. coli bacterial conjugation is often regarded as the bacterial equivalent of sexual reproduction or mating since it involves the exchange of genetic material. However, it is not sexual reproduction, since no exchange of gamete occurs, and indeed no generation of a new organism: instead an existing organism is transformed." https://en.wikipedia.org/wiki/Bacterial_conjugation#:~:text=coli%20bacterial%20conjugation%20is%20often,the%20exchange%20of%20genetic%20material.&text=coli%20conjugation%20the%20donor%20cell,often%20a%20plasmid%20or%20transposon.
Help me justify the existence of the shitty speculative organism I invented in high school
Sorry if this isn't the sub for this, I'll move it somewhere else if necessary. When I was in high school, I wrote a short story with the premise that there had been a civilization of sapient aquatic beings on Earth about 2.4 billion years ago, which descended from anaerobic methane-producing archaea and were destroyed by the Great Oxygenation Event. (A few of these beings managed to survive in stasis until the modern day through a soft sci-fi plot device, but that's not relevant to this post.) I was thinking of creating a sequel to/expansion of the original idea, but unfortunately, I didn't know much about designing plausible speculative organisms, so when coming up with the "Shoalers" (As I called them.) I mostly just threw together all the cool terms I had learned from grade 11 biology class and by skimming wikipedia pages in order to make them as weird as possible, without concern for how well all the different traits fit together. I still don't really know that much, but I now know enough to know some aspects of the Shoalers' biology are a bit implausible. Fortunately, my past self's laziness is somewhat helpful, as I didn't define any of the Shoalers' evolutionary history beyond the fact that they descended from methanogenic archaea that had convergently evolved multicellularity, which gives me complete freedom when deciding how they could have plausibly evolved all their implausible traits. So, I was wondering if I could have some help coming up with broad explanations for why the Shoalers are the way that they are, hopefully with only minimal retconning of the traits I had previously established them as having. Here's the information about the Shoalers I established in the short story. I'd rather not retcon any of it, unless it's completely unsalvageable:
The Shoalers have a triradially symmetrical body shaped like a cylinder, which tapers into a single long flexible tail. They have no distinct head, but have a head-like cluster of organs at the anterior end of their body, consisting of three equidistantly-spaced "arms" which each have five "fingers", three toothless mouths (Three mouths?!?) near the base of each arm, and a single massive compound eye (which can see in nearly every direction except in the direction of the optic disk, because of the Shoalers' semitransparent skin.) between the three mouths. Adults can range from about 1.5 to about 3 meters in length, and from about 0.5 to about 1.75 meters in diameter.
Shoalers are primarily filter-feeders, (I think the idea is that they simultaneously suck up food and move around by inhaling water through their mouths, filtering out food, and then expelling it through three funnels further down their body? I never actually established how they propel themselves, now that I think about it.) but are also capable of photosynthesis, collecting sunlight through a dense coating of hair-like setae on their tail. (I really don't understand why I added this detail. Maybe at some point in my research I got confused and assumed that methanogens had to be autotrophic, and then assumed that if they were autotrophs they had to be photosynthetic? I didn't really understand the chemistry behind different forms of respiration. I still don't, really.)
Shoalers have thin and porous skin, and breath through cutaneous respiration. (Why would I do this??? Did I think a 3-meter-long active sapient organism that relies fully on anaerobic respiration wasn't implausible enough, so I had to make it passive anaerobic respiration too???)
A species of bioluminescent single-celled prokaryotes lives within the Shoalers' skin, which they are (somehow) capable of altering the colour and brightness of. Shoaler languages are based on bioluminescence and body language, rather than sound.
Internally, the Shoalers loosely resemble echinoderms, despite being unrelated. (That's literally all I said about their internal organs. I'm thinking I might just give them a water vascular system and otherwise ignore this statement.)
Shoalers have no biological sexes and reproduce asexually.
They're called "Shoalers" because they evolved to congregate in massive shoals as a defense against predation. As a relic of this instinct, Shoalers that have not interacted with other Shoalers recently tend to become rapidly anxious - Imagine how you would feel if you were locked in a tiny pitch-black room for X amount of time, and you will pretty much understand how a Shoaler would feel if left alone for the same amount of time.
The following information about the Shoalers isn't explicitly stated in the story I wrote, but I came up with during the process of writing the story or in the years afterwards. It can be retconned away, but it'd be nice to keep it if possible, I guess:
Shoalers continue to live in large "Shoals" (Capital S because it's now a unique socio-biological phenomenon rather than just them swimming together.) of about 15-30 individuals, which have evolved from a temporary anti-predator adaptation into a kinship group sort of analogous to an extended family or a small clan. Members of a given Shoal live in close proximity to each other, and coordinate their actions through informal consensus or, more rarely, deference towards a respected individual or group of individuals within the Shoal. While humans consider human society to be made up of individuals who may belong to different groups, Shoalers consider Shoaler society to be made of up of Shoals who are in turn made up of individuals. (e.g. A Shoaler democracy would probably operate under the principle of "One Shoal, one vote", and in most Shoaler languages, the term for "individual" might literally translate as "Shoal-appendage".)
Shoalers give live birth to about 70-80 young, which are about 2 centimeters long and non-sapient. These young are immediately abandoned by their parent, and about 95% percent of them die within their first two years of life. After reaching 2 years old, at which point a juvenile Shoaler is about as intelligent as a 4-year-old human, they are usually adopted by a nearby Shoal, whose members collectively raise and educate them.
Shoalers have a symbiotic relationship with a coral-like prokaryotic colonial organism which evolved to shed small pieces of its body into the water to attract Shoalers and other related filter-feeders, who would then unwittingly spread the colonial organism's larvae (disguised amongst the particulate) to new places. The Shoalers underwent a societal revolution similar to the agricultural revolution when they learned to domesticate this organism as both a source of food and a construction material, using scaffolds and pruning to grow it into the shape of buildings.
So, I guess my questions would be:
Is the high concept of the story - That unbeknownst to humanity, multicellular life first evolved in the anoxic oceans of the Neoarchaen, culminating in a civilization of sapient obligate anaerobes, before it was all destroyed by the Great Oxygenation Event - plausible in of itself? Is methanogenic respiration efficient enough to support a large multicellular organism? Is it plausible that humanity would have never stumbled on fossil evidence of these lifeforms, as long as they were all soft-bodied?
Why would large, motile organisms like the ancestors of the Shoalers develop triradial symmetry over bilateral symmetry, and why wouldn't they be outcompeted by organisms with a bilateral symmetry and/or secondarily evolve bilateral symmetry themselves? On one hand, a three-sided cylindrical body is pretty close to the "torpedo" shape converged upon by fast aquatic animals like sharks and dolphins, and I could see it providing a situational boost to maneuverability since they would never have to rotate very far to point two of their limbs in a given direction, but on the other hand, I can't see any advantage to retaining a triradial body that would outweigh the benefits of either specializing one of the three limbs as a dorsal fin/something else and adapting the other two limbs into pectoral fins, or just not expending the energy to grow a whole-ass third limb that's probably redundant most of the time.
Speaking of which, why and how the hell would they develop three different mouths? I'm thinking if their one big eye and brain are located in-between the mouth's three respective digestive tracts, that would explain why they don't slowly move towards each other and merge into one (cf. the size constraints on a cephalopod's donut-shaped brain.) but that doesn't explain why one hasn't grown larger and become the main mouth while the other two become vestigial, or why such a bizarre and inefficient system would develop in the first place.
Is having one big compound eye implausible? What kind of compound eye would work best?
Now that I think about it, I never established what their three limbs were originally used for, before the sapient Shoalers emerged and repurposed them for tool-use. Maybe rather than locomotion (which they would achieve through jet propulsion and/or their tail) the Shoaler's ancestors originally used their three limbs to catch food, developing "fingers" on the ends to either better restrain prey or provide a larger surface area for filter-feeding, as well as muscles for curling the limbs inwards in order to transfer food to their mouths, then a reef-dwelling species made these limbs more dexterous in order to use them to rapidly change speed and direction by pulling on and pushing off the structures of the reef, with the Shoalers finally adapting them in order to manipulate tools. Is that at all plausible?
How do I explain their ability to perform photosynthesis? I was thinking of explaining it as the result of an endosymbiotic relationship between the Shoalers and an anaerobic photosynthetic microorganism, (perhaps even the same one they use to bioluminescence?) akin to the emerald sea slug, but I don't know if that makes any sense - It seems unrealistic to me that this extremely specific trait would just so happen to evolve in the one lineage that also developed sapience, so presumably its a feature of a much larger clade of which the Shoalers are just one member, and I don't know how plausible it is to have a significant portion of the animal-analogue species supplement their food supply with photosynthesis instead of wholly specializing as either heterotrophs or autotrophs.
How the hell do creatures that large survive using passive respiration, and why haven't they developed a better solution? I don't even have the beginnings of an idea of how to explain this one.
How would they control the bioluminescent microorganisms in their body with enough sophistication to use them to communicate?
Why wouldn't the ancestors of the Shoalers have ever developed sexual reproduction? My only idea is that they could have some sort of ability to exchange genetic material akin to bacterial conjugation, sidestepping the genetic diversity issues inherent to asexual reproduction. I'm hesitant about that idea though, if only because it seems like a roundabout way of giving them the ability to reproduce sexually without calling it sexual reproduction.
Is it realistic that a filter-feeder as large as a Shoaler would develop shoaling behaviour? The only aquatic animals I can think of that are comparable in size and swim together in big groups are dolphins and orcas, and they're hunters, not filter-feeders.
Is their weird hybrid of r-strategist and K-strategist reproductive strategies, where they abandon their young for two years and then spend lots of energy raising the survivors, at all realistic? One obvious issue is the fact that there's seemingly no incentive for Shoals to adopt and raise new juvenile Shoalers, since they likely have no genetic relationship with each other - I was thinking a solution to this might be to say that newly-adopted Shoalers receive genetic material from the Shoal that adopts them, making the adoptee's future offspring descended from both the Shoal that birthed them and the Shoal that adopted them, and providing an evolutionary incentive for their adopter Shoal to raise and protect them. Is that at all plausible?
Is the weird pollinator-into-domesticator symbiotic evolution between the Shoalers and the colonial organism they use as a crop and building material plausible?
Are their any unrealistic elements to the Shoalers that I haven't realized are unrealistic (Or that I just forgot to mention) that need to be dealt with somehow? How should I deal with them?
Consider plasmid F. Plasmid F (for "fertility") is a plasmid, which is a small loop of DNA a few thousand base pairs in length. Plasmid F is found in Escherichiacoli. Now, plasmids are just loops of DNA. They do some things that living things do (reproduce, regulate their reproduction) but just as the bacterial chromosome is not alive, nor are plasmids. Plasmid F contains in its code a set of instructions to generate an object called a "sex pilus" (I swear I didn't come up with the name) that is a long, thin tube that sticks out of the cell. This swings around until it contacts another cell that doesn't contain plasmid F and then it conjugates. For plasmid F, the plasmid (a single strand of it) is transferred from the donor (male) cell to the recipient (female) cell. (This stuff was worked out in the 1950s and 1960s so the terminology is not very P.C.) OK. So that's plasmid F and we accept that plasmids are genetic elements, they can reproduce and transfer themselves from cell to cell, but they are not alive any more than the far more complex bacterial chromosome is. So now let's move it along a step. Suppose that a mutant of plasmid F comes along and it codes for a sex pilus that is unusually long (stop snickering). This pilus is long enough to contain the entirety of plasmid F! And then in a second mutation, this "extra long pilus" plasmid F now comes up with a pilus that completely detaches from the donor cell and floats around freely in the medium until it finds a recipient cell and then transfers itself in. Well, guess what? This hypothetical double-mutant plasmid F has now become a virus. And yet...it didn't suddenly become a living thing. It is still a plasmid, just one that can float around freely. And that is why viruses are not alive.
i.e. 20 glucose molecules linked together would have 19 bonds
Molecular formula
# of molecules * molecular formula - number of bonds * H20 (from hydrolysis)
i.e. when you bond 5 glucose molecules together you have to subtract 4H2O
pH/pOH
-log[H+] = pH
-log[OH-] = pOH
pH + pOH = 14
Leaf surface area
i.e. using graph paper to find surface area
Transpiration rate
Amount of water used / surface area / time
Labs
Transpiration Lab
Basically you take this potometer which measures the amount of water that gets sucked up by a plant that you have and you expose the plant to different environmental conditions (light, humidity, temperature) and see how fast the water gets transpired
Random stuff to know:
It’s hard to get it to work properly
A tight seal of vaseline keeps everything tidy and prevents water from evaporating straight from the tube, also allows for plant to suck properly
Water travels from high water potential to low water potential
2) Cell Structure & Function
Content
Cellular Components
Many membrane-bound organelles evolved from once free prokaryotes via endosymbiosis, such as mitochondria (individual DNA)
Compartmentalization allows for better SA:V ratio and helps regulate cellular processes
Cytoplasm: thick solution in each cell containing water, salts, proteins, etc; everything - nucleus
Cytoplasmic streaming: moving all the organelles around to give them nutrients, speeds up reactions
Cytosol: liquid of the cytoplasm (mostly water)
Plasma Membrane: separates inside of cell from extracellular space, controls what passes through amphipathic area (selectively permeable)
Aquaporin: hole in membrane that allows water through
Cell Wall: rigid polysaccharide layer outside of plasma membrane in plants/fungi/bacteria
Bacteria have peptidoglycan, fungi have chitin, and plants have cellulose and lignin
Turgor pressure pushes the membrane against the wall
Nucleus: contains genetic information
Has a double membrane called the nuclear envelope with pores
Nucleolus: in nucleus, produces ribosomes
Chromosomes: contain DNA
Centrioles: tubulin thing that makes up centrosome in the middle of a chromosome
Smooth Endoplasmic Reticulum: storage of proteins and lipids
Rough Endoplasmic Reticulum: synthesizes and packages proteins
Chloroplasts: photosynthetic, sunlight transferred into chemical energy and sugars
More on this in photosynthesis
Vacuoles: storage, waste breakdown, hydrolysis of macromolecules, plant growth
Plasmodesmata: channels through cell walls that connect adjacent cells
Golgi Apparatus: extracellular transport
Lysosome: degradation and waste management
Mutations in the lysosome cause the cell to swell with unwanted molecules and the cell will slow down or kill itself
Mitochondria: powerhouse of the cell
Mutations in the mitochondria cause a lack of deficiency of energy in the cell leading to an inhibition of cell growth
Vesicles: transport of intracellular materials
Microtubules: tubulin, stiff, mitosis, cell transport, motor proteins
Microfilaments: actin, flexible, cell movement
Flagella: one big swim time
Cilia: many small swim time
Peroxisomes: bunch of enzymes in a package that degrade H202 with catalase
Ribosomes: protein synthesis
Microvilli: projections that increase cell surface area like tiny feetsies
In the intestine, for example, microvilli allow more SA to absorb nutrients
Cytoskeleton: hold cell shape
Cellular Transport
Passive transport: diffusion
Cell membranes selectively permeable (large and charged repelled)
Tonicity: osmotic (water) pressure gradient
Cells are small to optimize surface area to volume ratio, improving diffusion
Primary active transport: ATP directly utilized to transport
Secondary active transport: something is transported using energy captured from movement of other substance flowing down the concentration gradient
Endocytosis: large particles enter a cell by membrane engulfment
Phagocytosis: “cell eating”, uses pseudopodia around solids and packages it within a membrane
Pinocytosis: “cell drinking”, consumes droplets of extracellular fluid
Receptor-mediated endocytosis: type of pinocytosis for bulk quantities of specific substances
Exocytosis: internal vesicles fuse with the plasma membrane and secrete large molecules out of the cell
Ion channels and the sodium potassium pump
Ion channel: facilitated diffusion channel that allows specific molecules through
Sodium potassium pump: uses charged ions (sodium and potassium)
Membrane potential: voltage across a membrane
Electrogenic pump: transport protein that generates voltage across a membrane
Proton pump: transports protons out of the cell (plants/fungi/bacteria)
Cotransport: single ATP-powered pump transports a specific solute that can drive the active transport of several other solutes
Bulk flow: one-way movement of fluids brought about by pressure
Dialysis: diffusion of solutes across a selective membrane
Cellular Components Expanded: The Endomembrane System
Nucleus + Rough ER + Golgi Bodies
Membrane and secretory proteins are synthesized in the rough endoplasmic reticulum, vesicles with the integral protein fuse with the cis face of the Golgi apparatus, modified in Golgi, exits as an integral membrane protein of the vesicles that bud from the Golgi’s trans face, protein becomes an integral portion of that cell membrane
Calculations
Surface area to volume ratio of a shape (usually a cube)
U-Shaped Tube (where is the water traveling)
Solution in u-shaped tube separated by semi-permeable membrane
find average of solute (that is able to move across semi permeable membrane)
add up total molar concentration on both sides
water travels where concentration is higher
Water Potential = Pressure Potential + Solute Potential
Solute Potential = -iCRT
i = # of particles the molecule will make in water
C = molar concentration
R = pressure constant (0.0831)
T = temperature in kelvin
Labs
Diffusion and Osmosis
Testing the concentration of a solution with known solutions
Dialysis bag
Semipermeable bag that allows the water to pass through but not the solute
Potato core
Has a bunch of solutes inside
Relevant Experiments
Lynne Margolis: endosymbiotic theory (mitochondria lady)
Chargaff: measured A/G/T/C in everything (used UV chromatography)
Franklin + Watson and Crick: discovered structure of DNA; Franklin helped with x ray chromatography
3) Cellular Energetics
Content
Reactions and Thermodynamics
Baseline: used to establish standard for chemical reaction
Catalyst: speeds up a reaction (enzymes are biological catalysts)
Exergonic: energy is released
Endergonic: energy is consumed
Coupled reactions: energy lost/released from exergonic reaction is used in endergonic one
Laws of Thermodynamics:
First Law: energy cannot be created nor destroyed, and the sum of energy in the universe is constant
Second Law: energy transfer leads to less organization (greater entropy)
Third Law: the disorder (entropy) approaches a constant value as the temperature approaches 0
Cellular processes that release energy may be coupled with other cellular processes
Loss of energy flow means death
Energy related pathways in biological systems are sequential to allow for a more controlled/efficient transfer of energy (product of one metabolic pathway is reactant for another)
Bioenergetics: study of how energy is transferred between living things
Fuel + 02 = CO2 + H20
Combustion, Photosynthesis, Cellular Respiration (with slight differences in energy)
Enzymes
Speed up chemical processes by lowering activation energy
Structure determines function
Active sites are selective
Enzymes are typically tertiary- or quaternary-level proteins
Catabolic: break down / proteases and are exergonic
Anabolic: build up and are endergonic
Enzymes do not change energy levels
Substrate: targeted molecules in enzymatic
Many enzymes named by ending substrate in “-ase”
Enzymes form temporary substrate-enzyme complexes
Enzymes remain unaffected by the reaction they catalyze
Enzymes can’t change a reaction or make other reactions occur
Induced fit: enzyme has to change its shape slightly to accommodate the substrate
Cofactor: factor that help enzymes catalyze reactions (org or inorg)
Examples: temp, pH, relative ratio of enzyme and substrate
Organic cofactors are called coenzymes
Denaturation: enzymes damaged by heat or pH
Regulation: protein’s function at one site is affected by the binding of regulatory molecule to a separate site
Enzymes enable cells to achieve dynamic metabolism - undergo multiple metabolic processes at once
Cannot make an endergonic reaction exergonic
Steps to substrates becoming products
Substrates enters active site, enzyme changes shape
Substrates held in active site by weak interactions (i.e. hydrogen bonds)
Substrates converted to product
Product released
Active site available for more substrate
Rate of enzymatic reaction increases with temperature but too hot means denaturation
Inhibitors fill the active site of enzymes
Some are permanent, some are temporary
Competitive: block substrates from their active sites
Non competitive (allosteric): bind to different part of enzyme, changing the shape of the active site
Allosteric regulation: regulatory molecules interact with enzymes to stimulate or inhibit activity
Enzyme denaturation can be reversible
Cellular Respiration
Steps
Glycolysis
Acetyl co-A reactions
Krebs / citric acid cycle
Oxidative phosphorylation
Brown fat: cells use less efficient energy production method to make heat
Absorption vs action spectrum (broader, cumulative, overall rate of photosynthesis)
Components
Chloroplast
Mesophyll: interior leaf tissue that contains chloroplasts
Pigment: substance that absorbs light
Steps
Light-Dependent Reaction
Light-Independent (Dark) Reaction (Calvin Cycle)
Anaerobic Respiration (Fermentation)
Glycolysis yields 2ATP + 2NADH + 2 Pyruvate
2NADH + 2 Pyruvate yields ethanol and lactate
Regenerates NAD+
Calculations
Calculate products of photosynthesis & cellular respiration
Labs
Enzyme Lab
Peroxidase breaks down peroxides which yields oxygen gas, quantity measured with a dye
Changing variables (i.e. temperature) yields different amounts of oxygen
Photosynthesis Lab
Vacuum in a syringe pulls the oxygen out of leaf disks, no oxygen causes them to sink in bicarbonate solution, bicarbonate is added to give the disks a carbon source for photosynthesis which occurs at different rates under different conditions, making the disks buoyant
Cellular Respiration Lab
Use a respirometer to measure the consumption of oxygen (submerge it in water)
You put cricket/animal in the box that will perform cellular respiration
You put KOH in the box with cricket to absorb the carbon dioxide (product of cellular respiration)-- it will form a solid and not impact your results
Relevant Experiments
Engelmann
Absorption spectra dude with aerobic bacteria
4) Cell Communication & Cell Cycle
Content
Cell Signalling
Quorum sensing: chemical signaling between bacteria
See Bonnie Bassler video
Taxis/Kinesis: movement of an organism in response to a stimulus (chemotaxis is response to chemical)
Ligand: signalling molecule
Receptor: ligands bind to elicit a response
Hydrophobic: cholesterol and other such molecules can diffuse across the plasma membrane
Hydrophilic: ligand-gated ion channels, catalytic receptors, G-protein receptor
Signal Transduction
Process by which an extracellular signal is transmitted to inside of cell
Pathway components
Signal/Ligand
Receptor protein
Relay molecules: second messengers and the phosphorylation cascade
DNA response
Proteins in signal transduction can cause cancer if activated too much (tumor)
RAS: second messenger for growth factor-- suppressed by p53 gene (p53 is protein made by gene) if it gets too much
Response types
Gene expression changes
Cell function
Alter phenotype
Apoptosis- programmed cell death
Cell growth
Secretion of various molecules
Mutations in proteins can cause effects downstream
Pathways are similar and many bacteria emit the same chemical within pathways, evolution!
Feedback
Positive feedback amplifies responses
Onset of childbirth, lactation, fruit ripening
Negative feedback regulates response
Blood sugar (insulin goes down when glucagon goes up), body temperature
Cell cycle
Caused by reproduction, growth, and tissue renewal
Checkpoint: control point that triggers/coordinates events in cell cycle
Mitotic spindle: microtubules and associated proteins
Cytoskeleton partially disassembles to provide the material to make the spindle
Elongates with tubulin
Shortens by dropping subunits
Aster: radial array of short microtubules
Kinetochores on centrosome help microtubules to attach to chromosomes
Broke apart liver cells and realized the significance of the signal transduction pathway, as the membrane and the cytoplasm can’t activate glycogen phosphorylase by themselves
5) Heredity
Content
Types of reproduction
Sexual: two parents, mitosis/meiosis, genetic variation/diversity (and thus higher likelihood of survival in a changing environment)
Asexual: doesn’t require mate, rapid, almost genetically identitical (mutations)
Binary fission (bacteria)
Budding (yeast cells)
Fragmentation (plants and sponges)
Regeneration (starfish, newts, etc.)
Meiosis
One diploid parent cell undergoes two rounds of cell division to produce up to four haploid genetically varied cells
n = 23 in humans, where n is the number of unique chromosomes
Meiosis I
Prophase: synapsis (two chromosome sets come together to form tetrad), chromosomes line up with homologs, crossing over
Metaphase: tetrads line up at metaphase plate, random alignment
Anaphase: tetrad separation, formation at opposite poles, homologs separate with their centromeres intact
Telophase: nuclear membrane forms, two haploid daughter cells form
Meiosis II
Prophase: chromosomes condense
Metaphase: chromosomes line up single file, not pairs, on the metaphase plate
Anaphase: chromosomes split at centromere
Telophase: nuclear membrane forms and 4 total haploid cells are produced
Genetic variation
Crossing over: homologous chromosomes swap genetic material
Independent assortment: homologous chromosomes line up randomly
Random fertilization: random sperm and random egg interact
Gametogenesis
Spermatogenesis: sperm production
Oogenesis: egg cells production (¼ of them degenerate)
Fundamentals of Heredity
Traits: expressed characteristics
Gene: “chunk” of DNA that codes for a specific trait
Homologous chromosomes: two copies of a gene
Alleles: copies of chromosome may differ bc of crossing over
Homozygous/Heterozygous: identical/different
Phenotype: physical representation of genotype
Generations
Parent or P1
Filial or F1
F2
Law of dominance: one trait masks the other one
Complete: one trait completely covers the other one
Incomplete: traits are both expressed
Codominance: traits combine
Law of segregation (Mendel): each gamete gets one copy of a gene
Law of independent assortment (Mendel): traits segregate independently from one another
Locus: location of gene on chromosome
Linked genes: located on the same chromosome, loci less than 50 cM apart
Gene maps and linkage maps
Nondisjunction: inability of chromosomes to separate (ex down syndrome)
Polygenic: many genes influence one phenotype
Pleiotropic: one gene influences many phenotypes
Epistasis: one gene affects another gene
Mitochondrial and chloroplast DNA is inherited maternally
Diseases/Disorders
Genetic:
Tay-Sachs: can’t break down specific lipid in brain
Sickle cell anemia: misshapen RBCs
Color blindness
Hemophilia: lack of clotting factors
Chromosomal:
Turner: only one X chromosome
Klinefelter: XXY chromosomes
Down syndrome (trisomy 21): nondisjunction
Crosses
Sex-linked stuff
Blood type
Barr bodies: in women, two X chromosomes; different chromosomes expressed in different parts of the body, thus creating two different phenotype expressions in different places
Calculations
Pedigree/Punnett Square
Recombination stuff
Recombination rate = # of recombinable offspring/ total offspring (times 100) units: map units
Relevant Experiments
Mendel
6) Gene Expression and Regulation
Content
DNA and RNA Structure
Prokaryotic organisms typically have circular chromosomes
Plasmids = extrachromosomal circular DNA molecules
Purines (G, A) are double-ringed while pyrimidines (C, T, U) have single ring
snRNA - small nuclear RNA (bound to snRNPs - small nuclear ribonucleoproteins)
miRNA - microRNA (regulatory)
DNA Replication
Steps:
Helicase opens up the DNA at the replication fork.
Single-strand binding proteins coat the DNA around the replication fork to prevent rewinding of the DNA.
Topoisomerase works at the region ahead of the replication fork to prevent supercoiling.
Primase synthesizes RNA primers complementary to the DNA strand.
DNA polymerase III extends the primers, adding on to the 3' end, to make the bulk of the new DNA.
RNA primers are removed and replaced with DNA by DNA polymerase I.
The gaps between DNA fragments are sealed by DNA ligase.
Protein Synthesis
61 codons code for amino acids, 3 code as STOP - UAA, UAG, UGA - 64 total
Transcription Steps:
RNA polymerase binds to promoter (before gene) and separate the DNA strands
RNA polymerase fashions a complementary RNA strand from a DNA strand
Coding strand is same as RNA being made, template strand is complementary
Terminator on gene releases the RNA polymerase
RNA Processing Steps (Eukaryotes):
5’ cap and 3’ (poly-A tail, poly A polymerase) tail is added to strand (guanyl transferase)
Splicing of the RNA occurs in which introns are removed and exons are added by spliceosome
Cap/tail adds stability, splicing makes the correct sequence (“gibberish”)
Translation Steps:
Initiation complex is the set up of a ribosome around the beginning of an mRNA fragment
tRNA binds to codon, amino acid is linked to other amino acid
mRNA is shifted over one codon (5’ to 3’)
Stop codon releases mRNA
Gene Expression
Translation of mRNA to a polypeptide occurs on ribosomes in the cytoplasm as well as rough ER
Translation of the mRNA occurs during transcription in prokaryotes
Genetic info in retroviruses is an exception to normal laws: RNA to DNA is possible with reverse transcriptase, which allows the virus to integrate into the host’s DNA
Regulatory sequences = stretches of DNA that interact with regulatory proteins to control transcription
Epigenetic changes can affect expression via mods of DNA or histones
Observable cell differentiation results from the expression of genes for tissue-specific proteins
Induction of transcription factors during dev results in gene expression
Prokaryotes: operons transcribed in a single mRNA molecule, inducible system
Eukaryotes: groups of genes may be influenced by the same transcription factors to coordinate expression
Promoters = DNA sequences that RNA polymerase can latch onto to initiate
Negative regulators inhibit gene expression by binding to DNA and blocking transcription
Acetylation (add acetyl groups)- more loosely wound/ less tightly coiled/compressed
Methylation of DNA (add methyl groups) - less transcription- more tightly wound
Mutation and Genetic Variation
Disruptions in genes (mutations) change phenotypes
Mutations can be +/-/neutral based on their effects that are conferred by the protein formed - environmental context
Errors in DNA replication or repair as well as external factors such as radiation or chemical exposure cause them
Mutations are the primary source of genetic variation
Horizontal acquisition in prokaryotes - transformation (uptake of naked DNA), transduction (viral DNA transmission), conjugation (cell-cell DNA transfer), and transposition (DNA moved within/between molecules) - increase variation
Related viruses can (re)combine genetic material in the same host cell
Types of mutations: frameshift, deletion, insertion
Genetic Engineering
Electrophoresis separates molecules by size and charge
PCR magnifies DNA fragments
Bacterial transformation introduces DNA into bacterial cells
Operons
Almost always prokaryotic
Promoter region has operator in it
Structural genes follow promoter
Terminator ends operon
Regulatory protein is active repressor
Active repressor can be inactivated
Enhancer: remote gene that require activators
RNAi: interference with miRNA
Anabolic pathways are normally on and catabolic pathways are normally off
Calculations
Transformation efficiency (colonies/DNA)
Numbers of base pairs (fragment lengths)
Cutting enzymes in a plasmid or something (finding the lengths of each section)
Labs
Gel Electrophoresis Lab
Phosphates in DNA make it negative (even though it’s an acid!), so it moves to positive terminal on the board
Smaller DNA is quicc, compare it to a standard to calculate approx. lengths
Bacterial Transformation Lab
Purpose of sugar: arabinose is a promoter which controls the GFP in transformed cells, turns it on, also green under UV
Purpose of flipping upside down: condensation forms but doesn’t drip down
Purpose of heat shock: increases bacterial uptake of foreign DNA
Plasmids have GFP (green fluorescent protein) and ampicillin resistance genes
Calcium solution puts holes in bacteria to allow for uptake of plasmids
PCR Lab
DNA + primers + nucleotides + DNA polymerase in a specialized PCR tube in a thermal cycler
Primers bind to DNA before it can repair itself, DNA polymerase binds to the primers and begins replication
After 30 cycles, there are billions of target sequences
Relevant Experiments
Avery: harmful + harmless bacteria in mice, experimented with proteins vs DNA of bacteria
Griffith: Avery’s w/o DNA vs protein
Hershey and Chase: radioactively labeled DNA and protein
Melson and Stahl: isotopic nitrogen in bacteria, looked for cons/semi/dispersive DNA
Beadle and Tatum: changed medium’s amino acid components to find that a metabolic pathway was responsible for turning specific proteins into other proteins, “one gene one enzyme”
Nirenberg: discovered codon table
7) Natural Selection
Scientific Theory: no refuting evidence (observation + experimentation), time, explain a brand/extensive range of phenomena
Theory of Natural Selection
Definition
Not all offspring (in a population) will survive
Variation among individuals in a population
Some variations were more favourable than others in a particular environment
Those with more favourable variations were more likely to survive and reproduce.
These favourable variations were passed on and increased in frequency over time.
Types of Selection:
Directional selection: one phenotype favored at one of the extremes of the normal distribution
”Weeds out” one phenotype
Ony can happen if a favored allele is already present
Stabilizing Selection: Organisms within a population are eliminated with extreme traits
Favors “average” or medium traits
Ex. big head causes a difficult delivery; small had causes health deficits
Disruptive Selection: favors both extremes and selects against common traits
Ex. sexual selection (seems like directional but it’s not because it only affects one sex, if graph is only males then directional)
Competition for limited resources results in differential survival, favourable phenotypes are more likely to survive and produce more offspring, thus passing traits to subsequent generations.
Biotic and abiotic environments can be more or less stable/fluctuating, and this affects the rate and direction of evolution
Convergent evolution occurs when similar selective pressures result in similar phenotypic adaptations in different populations or species.
Divergent evolution: groups from common ancestor evolve, homology
Different genetic variations can be selected in each generation.
Environments change and apply selective pressures to populations.
Evolutionary fitness is measured by reproductive success.
Natural selection acts on phenotypic variations in populations.
Some phenotypic variations significantly increase or decrease the fitness of the organism in particular environments.
Through artificial selection, humans affect variation in other species.
Humans choose to cause artificial selection with specific traits, accidental selection caused by humans is not artificial
Random occurrences
Mutation
Genetic drift - change in existing allele frequency
Migration
Reduction of genetic variation within a given population can increase the differences between populations of the same species.
Conditions for a population or an allele to be in Hardy-Weinberg equilibrium are
Large population size
Absence of migration
No net mutations
Random mating
Absence of selection
Changes in allele frequencies provide evidence for the occurrence of evolution in a population.
Small populations are more susceptible to random environmental impact than large populations.
Gene flow: transference of genes/alleles between populations
Speciation: one species splits off into multiple species
Sympatric (living together i.e. disruption) Allopatric (physically separate, i.e. founder effect) Parapatric (habitats overlapping)
Polyploidy (autopolyploidy), sexual selection
Species: group of populations whose members can interbreed and produce healthy, fertile offspring but can’t breed with other species (ex. a horse and donkey can produce a mule but a mule is nonviable, so it doesn’t qualify)
Morphological definition: body shape and structural characteristics define a species
Ecological species definition: way populations interact with their environments define a species
Phylogenetic species definition: smallest group that shares a common ancestor is a species
Prezygotic barriers: barriers to reproduction before zygote is formed
Geographical error: two organisms are in different areas
Behavioural error (i.e. mating rituals aren’t the same)
Mechanical error: “the pieces don’t fit together”
Temporal error (i.e. one organism comes out at night while the other comes out in the day)
Zygotic/Gametic isolation: sperm and egg don’t physically meet
Postzygotic barriers: barriers to reproduction after zygote is formed
Hybrid viability: developmental errors of offspring
Hybrid fertility: organism is sterilized
Hybrid breakdown: offspring over generations aren’t healthy
Hybrid zone: region in which members of different species meet and mate
Reinforcement: hybrids less fit than parents, die off, strength prezygotic barriers
Fusion: two species may merge into one population
Stability: stable hybrid zones mean hybrids are more fit than parents, thus creating a stable population, but can be selected against in hybrid zones as well
Punctuated equilibria: long periods of no or little change evolutionarily punctuated by short periods of large change, gradualism is just slow evolution
Evidence of evolution
Paleontology (Fossils)
Comparative Anatomy
Embryology: embryos look the same as they grow
Biogeography: distribution of flora and fauna in the environment (pangea!)
Biochemical: DNA and proteins and stuff, also glycolysis
Phylogenetic trees
Monophyletic: common ancestor and all descendants
Polyphyletic: descendants with different ancestors
Paraphyletic: leaving specifies out of group
Out group: basal taxon, doesn’t have traits others do
Cline: graded variation within species (i.e. different stem heights based on altitude)
Anagenesis: one species turning into another species
Cladogenesis: one species turning into multiple species
Taxon: classification/grouping
Clade: group of species with common ancestor
Horizontal gene transfer: genes thrown between bacteria
Shared derived characters: unique to specific group
Shared primitive/ancestral characters: not unique to a specific group but is shared within group
Origins of life
Stages
Inorganic formation of organic monomers (miller-urey experiment)
Inorganic formation of organic polymers (catalytic surfaces like hot rock or sand)
Protobionts and compartmentalization (liposomes, micelles)
DNA evolution (RNA functions as enzyme)
Shared evolutionary characteristics across all domains
Membranes
Cell comm.
Gene to protein
DNA
Proteins
Extant = not extinct
Highly conserved genes = low rates of mutation in history due to criticalness (like electron transport chain)
Molecular clock: dating evolution using DNA evidence
Extinction causes niches for species to fill
Eukaryotes all have common ancestor (shown by membrane-bound organelles, linear chromosomes, and introns)
Calculations
Hardy-Weinberg
p + q = 1
p^2 + 2pq +q^2 = 1
Chi Squared
Labs
Artificial Selection Lab
Trichrome trait hairs
Anthocyanin for second trait (purple stems)
Function of the purple pigment?
Function of trichome hairs?
BLAST Lab
Putting nucleotides into a database outputs similar genes
Relevant Experiments
Darwin
Lamarck
Miller-Urey
Slapped some water, methane, ammonia, and hydrogen is some flasks and simulated early earth with heat and stuff and it made some amino acids.
I'm a biology student who loves the game and here is my interpretation of how the infection first began!
Hello, I'm a biology student who loves the game and based on the following evidence I have drawn a few conclusions, but before I get into those, yes I know it's just a game and yes I know I'm reading too deep into it, but I did this for fun and wanted to share: Supply drops are a sign of existing infrastructure. Or maybe it's automated with no one flying it, remaining in service after all other services have died off or been shut down. Zombies don't freeze in the cold and need to rest, so they are alive. The infection affects humans and other animals, so the infection is zoonotic. Anti-biotics help cure the infection. So the infection is not a virus, but rather a bacteria. The infection spreads via bites. sratches, and lives in the blood. The bacteria who closely matches all these mentioned criteria is Capnocytophaga. A bacterial disease that lives in dog's mouths spreads through saliva, most often via bites. The bacteria, if given the right circumstances can infect the blood and can progress to become systemic. The only reason it rarely is a lethal hazard is due to how slow it reproduces....DUN DUN DUUUUUUUUN Patient Zero monologue: "'UN imposes sanctions on anti-biotics as rise of superbugs poses worldwide crisis' And that's how the end began. That one headline forced the entire scientific and medical community to scramble like roaches on bathroom tile. Antibiotics had been our go-to cure for so many ailments, but all of a sudden our go-to was forced into being a last resort. Antibiotics could only be prescribed if there was a lethal threat. So what then? What would people be prescribed for their stomach ache? Or, god forbid, someone has to deal with a stuffy nose? The horror. Millions of dollars went into funding genetic research. It was the most promising foe to face the villainous bacteria.The most effective technique was dubbed, 'Conjugation Elimination.' If you don't know, conjugation is the act of a bacteria piercing another bacteria, with a special part called a pilus, that injects a copy of genetic material. The recipient bacteria is then able to utilize that material. In simpler terms, bacteria 1 stabs bacteria 2 with a sillystraw and blows a load into bacteria 2, now bacteria 2 is genetically different than it was before. Conjugation Elimination takes advantage of this event by designing bacteria with the pilus, but that transfers two different genes. One gene to posses the pilus and one gene that inhibits reproduction. Before long, the mass population of bacteria in a host would be incapable of reproduction and die off. Pretty soon this was the ultimate technique to cure all things bacteria related. And it was a fortune if you didn't have insurance. We lucky few who's government had decided health was a privilege had to pay arm and leg for these treatments. Damn pharmaceuticals were all over patenting specific bacteria treatments. It all seemed so easy. All you had to do was inject some DNA into a bacteria cell and you had a cure. How could you mess that up? How could I have made this...It was easy for the most part to get everything I needed to do my own genetic engineering. It started off as me making some E-coli glow or making a bacteria explode when it came in contact with water. And then Arrow got sick, he was a bit older, sure, but he was my dog. I figured he had a Capnocytophaga bacterial infection in his mouth. No problem, I've made E-coli glow, I could recreate Conjugation Elimination. It may have been a felony to conduct genetic engineering without a permit, but all I needed to know were the genetic sequnces for the pilus and the gene that inhibits preproduction. Easy...Days spent in my dimly lit at-home lab, hunched over my microscope, sweat pooling in the optic lenses as my shakey hands forced a syringe into each bacteria cell. All for Arrow. Finaly I had a full batch, so I injected the modified bacteria into his left flank. All I had to do was go to sleep and awake to see my efforts being paid off. I was asleep before my head even hit the pillow. I was so exhausted. I just remember some surreal fever dream-like images from that night's sleep. Everything was red, and I remember feeling so hungry that I would eat anything. I was so excited to see Arrow back in his prime. But what I saw made my heart fall to the floor. The injection site was blistering and putrid. My poor Arrow had a think yellow slime-like foam coming from his mouth as he lay in the exact position I left him. His breathing was eradic and extremely elevated. What had I done? I must have done something wrong with the gene to inhibit reproduction. It must have increased reproduction at least ten fold. In my horror and sorrow I pet his head, pushing his ears back, his eye piercing my sole as if he was asking me, 'why?' I grabbed a near by rag to wipe away the slime from his mouth. And before I could react, he bit me, his canines went clean through my palm. I screamed and tried prying my hand free from the slimey grasp that was Arrow's mouth. I ran to my room as fast as I could and shut the door behind me. I could hear Arrow clawing away at the wood of my door. So I just sat there back against the door, terrified of my own dog and of what I had done. I couldn't call for help, or else I could face prison time. I've been here for hours now trying to devise a plan to somehow make it out of here alive without hurting my dog anymore. But my vision is getting blurry, my fingers are tingling, and my mucus is so thick I can barely breath. I'm so sorry Arrow. What have I done?"
I know single-celled organisms can reproduce asexually, but when a cell in a multicellular organism divides is that considered asexual reproduction too? Bonus points for sources.
The biosynthesis of nano particles with a great deal of effort by using a 'Green technology' that gives an innocuous, inexpensive and environmental friendly approach has been widely used. The technology also leads to fabricate wonder materials for biomedical applications. The in vitro green approaches for the reduction of metal ions furnishes a flexible method to obtain nano particles with control over their size and shape that can be attributed to the flexibility of changing the medium pH and reaction temperature. This review provides an outlook on a range of devices and tools that can make a system for detection of a therapeutic agent and to determine its action on an intended target, facilitating the research in diagnosis and prevention of cancer. The validation of nano particles with these exciting approaches may serve a strong foundation for modified chemotherapies in the next phase of clinical trials which would lead to profound changes in oncological practices by facilitating the realization of personalized medicines through demonstration of safety as well as efficacy in human clinical trials. Keywords: Green technology; Wonder materials; Personalized medicines; Cancer; Modified chemotherapy. Keywords: Green technology; Wonder materials; Personalized medicines; Cancer; Modified chemotherapy
Since the first preparation of the nano-particles that was carried out by Michael Faraday as early as in 1857, nano has become a flavor in the world of science. Nanoparticles, because of their exciting phenomenon of small size and variable shapes as spherical, wiry, tubular or sheet like has gained tremendous importance in the areas of medical diagnostics, drug delivery, chemical industry, textile industry and electronics. The utilization of this technology for the preparation of nano based products in area of research and development is growing at a great pace and is still expected to grow further in the coming years. The revolutionary impact of nanoscience in today's world is associated with the unforeseen hazards of these particles related to its method of synthesis. The intersection of nanotechnology and biotechnology has led to a fairly new area of technology; Nano biotechnology. This new area of research has been used in the development of nanomedicine that covers health care related areas of nanoscience and technology and serves structured nanodevices to analyze the specific biological system.
The synthesis of nanomaterials and effective fabrication of nanostructures follows two basic approaches; the top down approach involves successive cutting of larger parts to get nano sized particles of smaller and smaller dimensions. Bottom up approach follows building of material from atoms or molecules or by clusters. However, the disadvantage associated with the top down approach is the structural damage leading to imperfection of surface structure and patterns. Bottom up approaches provides a better chance to form nano structure with fewer defects although; the process frequently in Nanotechnology is not a newer concept.
A remarkable area of nanoresearch is often concern with the global environment. A great deal of effort has been put on that provides a better platform for the biosynthesis of nano particles by using plants [1] that are more innocuous, inexpensive, and environmentally friendly as they do not leave hazardous residues to pollute the atmosphere [2-6]. Although, the chemical method of synthesis requires less time for the fabrication of large quantity of nano particles, but are considered toxic and often lead to products that are non-eco-friendly [7]. In recent years, the in vitro green approaches for the reduction of metal ions provides a flexible, method to obtain nano particles with control over their size and shape that can be attributed to the flexibility of changing the medium pH and reaction temperature [8]. Variety of different plant species in combination with acid and salts of metals can be used to reduce ions of gold, copper, silver, platinum, iron and many others [9].
Facilitating the research in diagnosis and prevention of diseases, Nanotechnology offers a range of devices and tools that can make a system for detection of a therapeutic agent and to determine its action on an intended target. In recent years, nanotechnology has become a boon in cancer research by helping the oncologist to spot the cancer in early stages by detecting biomarkers that are undetectable through conventional detection techniques. Nanotechnology researchers have provided nano medicine based approaches that have been considered safe and effective treatment of cancer. Of the advances driven by National Cancer Institute (NCI), the discrimination of a healthy and cancerous cell by the use of photo luminescent nano particles will enable the clinician to identify the precancerous lesions thereby providing an early signal to reverse the premalignant changes and also allowing a time release of an anticancer drug sequentially at a desired location (www.cancer.gov). Tumors targeting objective has also influenced the role of Gold Nano particles (AuNP's) by their conjugation to Polyethylene Glycol (PEG) and unique biomarker binded antibodies on tumor cells. The fabrication of AuNP's with PEG prevented the unwanted aggregation and lengthened the retention time in blood by preferential accumulation of the particles in the tumor [10]. In another study, researchers at Cornell University have figured out the attachment criteria of gold nano particles by merging with iron oxide into colorectal cancer cell seeking the role of antibodies that can deliver the gold to the cancerous cell which can be heated by passing infrared laser because of the efficient property of the tiny particles of gold alloy which in turn will kill the cancerous cells [11]. Nano particle based drug delivery have also gain considerable potential for effective drug delivery in cancer therapy. The major challenge in the treatment of the disease is to get the drug at a specific place that is needed thereby avoiding side effects to other non-targeted organs. The limitations associated with the chemotherapeutics used against such dreaded disease are their non-restricted cytotoxicity in context to increasing dosage concentration. The nano particle formulation resulted in enabling the strategy of targeted drug delivery and these includes benefits of their small size which allow an easy penetration into the cell membrane, binding and stabilization of protein and lysosomal escape after endocytosis [12] thereby leading to the development of faster and safer medicines. Recently, the emergence of numerous proteinic and other drugs for targeting various cellular process have created a demand for the development of intelligent drug delivery system [13]. To meet the requirements for intelligent release of therapeutic agents to perform various function of detection, isolation and treatment of diseased conditions, a smart delivery system such as stimuli responsive nano materials will be a promising approach [14]. Carbon nano tube with its hollow structure is one of the wonder nano material that have motivated the researchers to explore their potential in the application of drug delivery to transport drug molecules, proteins and nucleotides. The size and shape of these materials allow them to enter living cells by adhering covalently or non-covalently to the surface without causing cell damage [15]. The potential application of carbon nano tubes in biotechnology is of much interest for exhibiting its advantages in biosensors [16], biomedical devices [17] and drug delivery systems [18]. However, the fictionalizations of CNTs is needed to reduce the chances of cytotoxicity and improving their biocompatible properties. The surface properties of the CNTs greatly influence their internalization behavior into the cell that is aided by the hydrophilicity of the tube. Also, the shorter length nano tubes are more effectively transported across the cell than the bundled CNTs [19]. Engineering of polymeric nanostructures for drug delivery inputs the use of a highly branched polymer known as Dendrimers that resemble the architecture of a tree. These multi branched macromolecules have attracted the researchers for various application in many fields due to its low polydispersity and high functionality. Dendrimers have offered escalating attention in scientific research particularly in the area of biomedical and pharmaceutics as a potential drug vehicle. A well-defined globular structure of these materials ensures a reproductive pharmacokinetics besides causing an increased cellular uptake of the drugs conjugated to them [20]. Mesoporous silica nanoparticles have reported exponential increase in research and are one of the hottest areas in the field of nanomedicine and nano biotechnology for its functional application as biocompatible nanocarriers. With a mesoporous structure, MSNs have been explored to treat various kind of disease parameters including tissue engineering [21] diabetes [22] inflammation as well as cancer [23]. The unique tailor able structure of mesoporous silica nano particle with their high surface area to large pore volume endow them to encapsulate variety of therapeutic agent to emphasize the targeted delivery into desired location [24]. Currently, delivery of variety of molecules of pharmaceutical interest has been appeared by employing mesoporous materials [25]. Mesoporous Silica Nanoparticle of size 50 to 300nm is considered facile for endocytosis without cytoxicity. Materials including MCM-41, SBA-15, SBA-1, SBA-3, HMS and MSU are groups of mesoporous biocompatibility and release kinetics of various drugs [13] materials that have been functionalized for improving the (Figure 1). Nanotechnology in toxicity outlook; a concern/ lacunae) Although the use of wide variety of nanostructures continued to alter the current scenario of cancer disease and diagnostics as a carrier system due to its biocompatibility and ability to reduce systemic toxicity, a crucial investigation regarding the toxicological effect of nanoparticles and the route of particle administration as a potential source of toxicity has to be emphasized which may arise due to its size, shape, dosage, charge as well as surface chemistry. The effect of these Nano materials results from its interaction particularly with the proteins that may lead to clumping of the protein molecules and linking up of various medical conditions. The large sized particles, once inside will move to circulation and may accumulate in organs including liver, spleen heart and brain. Also, direct cell to cell transfer of these particles is very unlikely as the pores between the cells are even smaller than their size. The absorption and opsonisation of nanomaterials or nanoparticles by serum protein may alter the effective size of the particles resulting in the change of an in vivo hydrodynamic diameter which is often lager than the size of in vitro Nanoparticles. There may be different trends of bio toxicity of nanomaterials in different ranges. Therefore, with the explosive increase in the research of this robust technology, it is necessary to have a concern outlook to fulfill the biomedical demand by well controlled fabrication of nano materials prior to be implemented in clinical practices.
The tremendous effort of the scientist towards protective utilization of nano particle based medicines or Nano medicines in fighting against cancer are showing promising outcomes. Concerning the issues associated with the drug circulation time and a localized therapy to the site of the disease, the utilization of Nano based therapeutics have a clear benefits than the unmodified drugs. The progress route of Nano therapeutics has already been demonstrated in the clinic. Doxorubicin contained in a hollow nanoparticle used to treat ovarian cancer was the first Nano based cancer drug approved by Food and Drug Administration. Likewise, the evidence of nanoparticle delivered clinical RNA interference (RNAi) published in Nature [26], first demonstrated by Calando Pharmaceuticals was approved by FDA in various stages of trials. The reduction of lung and toxillar lesion with a nanoparticle based therapeutic whereby the particles were combined with prostrate specific membrane antigen (PSMA) was reported by BIND Biosciences [27]. The outcome of the trial was greater efficacy compared to a lone drug at substantially lower doses. Furthermore, an albumin functionalized paclitaxel formulation of Celgene's Abraxane has got recognition for its necessary effect in the treatment of lung and pancreatic cancer along with breast cancer therapy by FDA (The-Scientist.com). Drs. Ciaus Radu, Owen Witte and Micheal Phelps have designed a series of positron emission tomography (PET) at the Nano system Biology Cancer Center. The system was used for assigning chemotherapy to the patients such as gemcitabine, cytarabine, fludarabine and others to treat metastatic breast cancer, ovarian, lung as well as leukaemia and lymphomas. A bio distribution study was also conducted in eight healthy volunteers. A nanoparticle magnetic resonance imaging contrast agent found on the surface of newly developing blood vessels associated with early detection of tumor was developed by Dr. Gregory Lanza and his team at Siteman Center of Cancer Nanotechnology Excellence, Washington University. Phase I clinical trial was performed for assessing the utility of the agent in early detection of tumor. A Nano sphere diagnostic company founded by Dr. Chad Mirkin at Nanomaterial for cancer diagnostic and therapeutic center has received approval by FDA for detecting cancer biomarkers by using Nano sensor. A clinical study using human tissue sample was performed to monitor low level of Prostate Specific Antigen (PSA) successfully Nanomaterial using silica, metal, polymers as well as carbon based particles have been demonstrated on preclinical front which shows satisfactory results. Recently, a report on multi drug delivery action and efficacy of nanoparticles to mediate resistance in relapsing cancer and improving triple negative breast cancer was by a team of researchers (The-Scientist.com). Other approaches including layer by layer siRNA delivery for breast cancer, sequential administration of Nanoparticles for pancreatic cancer treatment and tumor penetrating peptides against ovarian cancer are very recent. Thus, the validation of nanoparticles with these exciting approaches may serve a strong foundation for modified chemotherapies in the next phase of clinical trials which would lead to profound changes in oncological practices by facilitating the realization of personalized medicines through demonstration of safety as well as efficacy in human clinical trials.
Dealing with the most significant issue of cancer cells of Multi Drug Resistance (MDR) the heightened technology has shown inimitable benefits owing to a targeted delivery with its small sized vectors. The clinical prospects of nano materials are tremendously affecting the treatment of malignant cells which are more likely to possess the scene of multi drug resistance. The use of dendrimers as a promising material in nanooncology has been proved as an ideal candidate for delivering drugs to the tumor region, Besides this, dendrimers have been investigated for its use in killing bacterial cells as well as an agent for gene transfer and trans-membrane transport [12]. The case of synthesis of carbon nanotubes are considered as one of the strongest nano materials for considering the pathobiology of the disease under treatment. The efficient possibility of the nano tubes to target the cell receptors and blocking the cellular pathway of the disease by enabling the drug through the cell membrane is however a preferable system to kill the tumor. The promise of a successful cancer treatment using gold nano particles have led to bio affinity of gold nano particle probes for molecular and cellular imaging for early screening of the cancerous cells [28]. Mesoporous silica nano particles also meet the demand of cancer therapy by reducing the toxicity issues of many chemotherapeutic drugs. Due to the highly dynamic and heterogenous nature of the cancer, they can readily adapt to the stress imposed onto them. MSN-based nanocomposites target different phenotypes of a tumour thus holding a promising way to develop a co-operative therapy. FDA has recently approves a kind of ultrasound multimodal silica nanoparticles(Cornell dots) against advanced melanoma for even more specific diagnosis [24]. Besides that, the green method of synthesizing nanoparticles generated using plant phytochemicals can be also used in the discovery of new biomarkers and thus forming the basis of new drugs to fight cancer with refining diagnosis [29].
Nanotechnology covers a lot of domain today and will cover a lot more in near future. The creation of nanodevices with their changing form and multiple purposes as in cancer research will help in understanding the behavior of physiological markers of a disease and responsiveness of a drug [30-33]. Thus, exploiting the materials at atom and molecular level for the promising production of new materials controlling their shape and size at nano scale level has become a matter of potential concern. Also, it is necessary to envision that green method of synthesis of the base product of these devices has number of substantial benefits in context to several parameters including non-toxicity and cost effectiveness. However, the assessment of nano materials into human body while treating several disparities, the release of particulate materials into the disease environment as well as the extent to which they enter the intended sites of penetration will determine the ultimate risk of exposure particularly for those that cannot be metabolize by our body. Therefore, it is worth considering before formulating them into such scenarios.
Wanted to share my list of mnemonics that I found helpful for the MCAT. Many of these are from SDN but some are my own. I apologize in advanced for the crude and offensive ones but this often helps recall. If there's any mnemonics you use for MCAT topics not on here please share!
Beta vs. alpha carbohydrates
alpha = trans/down, beta = cis/up bow down to alpha, beta beat me up
Sympathetic vs. parasympathetic
Sympathetic = fight or flight, parasympathetic = rest & digest Paraplegics do a lot of sitting & resting (this is bad I'm really sorry but it works)
Electronegativity trend
FONCLBRISCH F > O > N > Cl > Br > I > S > C > H
Diatomic elements
BrINClHOF
Water soluble compounds
NAG SHAm Nitrates (NO3-) Acetate (CH3CO2-) Group 1 metal cations (Li, Na, K, Cs, Rb) Sulfates (SO42-) except with PMS Castro Bar Halogens except with PMS Ammonium (NH4+) PMS = Pb (Lead), Mercury (Hg), Silver (Ag) Castro Bar = Ca (Calcium), Str (Strontium), Ba (Barium)
Acid classifications
Increasing nuance/complexity when in alphabetical order. Arrenhius = acid forms H3O+ & base forms OH- in water (most elementary definition). Brownsted-Lowry = acids donate protons (H+) and bases accept them. Lewis = acids accept electron pairs and bases donate them.
La Chatelier's principle and equilibrium
When K & Q are in alphabetical order the arrow points to the direction the reaction will go to re-establish equilibrium. K > Q then reaction will go right, increasing product concentration. K < Q then reaction will go left, increasing reactant concentration.
Seminiferous tubules, epididymis, vas deferens, ejaculatory duct, urethra, penis SEVEN UP
mRNA post-processing
Exons Expressed, Introns in the trash
Taxonomy
Kingdom Phylum Class Order Family Genus Species King Philip Came Over For Gold & Silver
White blood cells
Neutrophils, lymphocytes, monocytes, eosinophils, basophils Nobody Likes Me Eating Badgers
Valence electrons
H likes to gain 1 e- to be stable, O 2, N 3, C 4 HONC 1234
Ecell site of redox
Reduction at cathode, oxidation at anode REDCAT ANOX
State functions
volume (V), Gibb's free energy (G), pressure (P), enthalphy (H), internal energy (E), entropy (S), temperature (T), potential energy (U), density (D) VG PHESTUD
Basic amino acids
histidine, arginine, lysine HAL
Cardiac cycle
systole = contraction, diastole = relaxation I Contracted a Cyst
Diverging lens image
diminished, upright, virtual DDUV
Acidic cations
Al, Fe, NH4, Zn, Cu, Be, Cr A Fact No Zebra Could Be Creepy
DNA order
DNA is read 3'-5' left to right like we read. But is synthesized 5'-3' largest to smallest just how a pyramid is built.
Bacterial conjugation
sexual reproduction in bacteria like a conjugal visit
Pancreas hormones
insulin, glucagon, somastatin I GLUed ON SOMe TATs to my pancreas
I need to teach a demo class for a job interview. It is 40 minutes and the audience 9th graders at a gifted and talented school. The subject I have been asked to cover is bacterial reproduction, both sexual and asexual.
What major points should I hit?
Any cool activities/ labs/ demos I can do?
I was thinking about talking about how fast bacteria can grow and some everyday effects of that (stinky socks etc) before talking about asexual reproduction and conjugation, transformation and transduction. Any suggestions or overall advice is welcomed.
Adnate - Where the gills or tubes under the cap of a fungus are perpendicular to the stipe or stem at the point of attachment Adnexed - Where the gills or tubes under the cap of a fungus sweep upwards before being attached to the stem Aerial mycelium - Hyphal elements growing above the agar surface. Agar - An extract from a seaweed used to solidify media. The agar used in mushrooms cultivation is usually available in powder form Agaric - A term describing mushrooms and toadstools having gills beneath a cap that is connected to a stipe or stem Alkaline - Having a pH greater than 7. Annulus - A ring of tissue left attached to the stem of a mushroom or toadstool when the veil connecting the cap and stem ruptures as the young fruitbody develops. Antibiotic - A class of natural and synthetic compounds that inhibit the growth of or kill other microorganisms. Ascomycetes - A group of fungi that have in common that they produce their sexual spores inside specialized cells (asci), which usually contain eight spores. Aseptic - Sterile condition: no unwanted organisms present Aseptic technique - Also sterile technique. Manipulating sterile instruments or culture media in such a way as to maintain sterility. Autoclave - Basically a big pressure cooker, sometimes operating at higher pressure than 15 PSI, thus achieving sterilization temperatures above 250?F. Axenic - Not contaminated; gnotobiotic: Said esp. of a medium devoid of all living organisms except those of a single Species
B
Bacteria - Unicellular microorganisms that may cause contamination in culture work. Grain spawn is very easily contaminated with bacteria. On the other hand there are some bacteria that are needed for the fruiting of agaricus. These are present in the casing soil. Basidiomycetes - A group of fungi which produce their spores externally on so called basidia. Often four spores are produced per basidium. Many basidiomycetes show clamp connections on their hyphae, ascomycetes never do. Most mushrooms are classified as basidiomycetes, whereas most molds are ascymycetic. Basidium (pl. basidia) - A cell that gives rise to a basidiospore. Basidia are characteristic of the basidiomycetes. Biological efficiency - The definition of biological efficiency (BE) in mushroom cultivation is: 1 pound fresh mushrooms from 1 pound dry Substrate indicates 100 % biological efficiency. This definition was first used by the agaricus industry to be able to compare different grow setups and Substrate compositions. Note that this is not the same as true thermodynamic efficiency. The BE of Psilocybe cubensis is easily somewhere in the range of 200%uFFFDbr> Birthing - Removing the fully colonized growth medium (like a cake from its jar) from whatever container it was kept in for colonization purposes and placing in an environment conducive to fruiting. Bolete - A group of fungi having tubes rather than gills beneath the cap Brown Rice Flour (BRF)- Ground brown rice. Many cultivators grind their own brown rice in a coffee grinder. Buffer - A system capable of resisting changes in pH even when acid or base is added, consisting of a conjugate acid-base pair in which the ratio of proton acceptor to proton donor is near unity. An example is gypsum, which is an additive that increases a material's pH while helping to buffer it, or keep it within a desriable (and higher) pH range.
C
CaCl2 - Calcium chloride (Brand names: Damp-Rid, Damp-Gone, Damp B Gone, Damp Away). See desiccant. CaCO3 - See calcium carbonate. Calcium sulfate - CaSO4. See gypsum. Carbon dioxide - CO2. A colorless, odorless, incombustible gas. Formed during respiration, combustion, and organic decomposition. Carpophore(s) - Commonly known as "mushrooms", the reproductive organs of the true body of the fungus, formed by the web of mycelium that colonize a substrate. Casing - Some mushrooms need a covering layer of soil with a specific microflora for Fruiting. Casing materials include peat and vermiculite; additives include calcium carbonate, calcium hydroxide (hydrated lime) and crushed oystershells. CaSO4 - Calcium sulfate. See gypsum. Cellulose - Glucose polysaccharide that is the main component of plant cell walls. Most abundant polysaccharide on earth, and common source of nourishment for cultivated fungi. Clone - A population of individuals all derived asexually from the same single parent. In mushroom cultivation placing a piece of mushroom tissue on agar medium in order to obtain growing mycelium is called cloning. This is not strictly related to the colloquial notion of cloning, and is simply a manipulation of the natural asexual reproduction system of fungi. CO2 - See carbon dioxide Cobweb mold - Common name for Dactylium, a mold that is commonly seen on the casing soil or parisitizing the mushroom. It is cobweb-like in appearance and first shows up in small scattered patches and then quickly runs over the entire surface of the its substrate. Coir - Coco coir. A short coarse fiber from the outer husk of a coconut. Used as a casing ingredient. Brand names include Bed-A-Beast . CVG aka Coir Verm Gypsum- This commonly used acronym is one of the most commonly used substrates for growing Psilocybe Cubensis. CVG can be sterilized or pasteurized unlike other substrates that would otherwise require pasteurization and can't be sterilized with the intention of spawning to bulk in open air. Coir, Coir Verm, Coir Gypsum, and Coir verm gypsum are all usable combinations. Colonization - The period of the mushroom cultivation starting at Inoculation during which the mycelium grows through the Substrate until it is totally permeated and overgrown. Compost - Selectively-fermented organic material. Compost is one desirable substrate for mushrooms, but may vary in its components. Coniferous - Pertaining to conifers, which bear woody cones containing naked seeds. Relevant in mushroom hunting. Contamination - Undesired foreign material (contaminants), frequently organisms, in a growing medium. Often the result of insufficient sterilisation or improper sterile technique. Cottony - Having a loose and coarse texture. Referred to a growth pattern of some fungi species or strains. Culture - A sample of a given (generally desired) organism. In mycology, mushroom mycelium growing on a culture medium. Culture medium - The material upon which a culture is developed. Micro-organisms differ in their nutritional needs, and so large number of different growth media have been developed, PD(Y)A (potato dextrose(yeast extract) agar) and MEA (malt extract agar) can be used for most cultivated mushrooms.
D
Deciduous - Trees and plants that shed their leaves at the end of the growing season. Relevant in mushroom hunting. Desiccant - An anhydrous (moistureless) substance, usually a powder or gel, used to absorb water from other substances. Two commonly used dessicants are calcium hydroxide and silica gel. Dessication permits mushrooms to be preserved for extended periods. Dextrose - A simple sugar used in agar formulations. Synonymous with glucose. Dikaryotic mycelium - Contains two nuclei and can therefore produce fruiting bodies. Diffusion - The movement of suspended or dissolved particles from a more concentrated region to a less concentrated region as a result of random movement on the microscopic scale. Diffusion tends to distribute particles uniformly throughout the available volume, given enough time, and occurs more rapidly at higher temperatures. Disinfection - To cleanse so as to destroy or prevent the growth of microorganisms, usually referring to rubbing or spraying the surfaces one wants to disinfect with lysol, diluted bleach solutions or alcohol.
E
Endospore - A metabolically dormant state by which some bacteria become more resistant to heat, chemicals, and other adverse conditions. Given the proper conditions, they will reactivate (germinate) and begin to multiply. Many bacterial endospores cannot be destroyed at boiling temperatures. This is important to mycologists because grains contain a high number of dormant endospores, though rice often contains few to none; thus, many grains must be pressure cooked to achieve sterilization, whereas brown rice flour may simply be boiled. Enzyme - A protein, synthesized by a cell, that acts as a catalyst for a specific chemical reaction.
F
Fermentation - Anaerobic (oxygen-less) decomposition. In mushroom cultivation, this often relates to composting. Easily-accessible nutrients may be degraded by micro-organism, making a substrate more selectively beneficial to the desired fungus. Unwanted fermentation may occur if the composted substrate is still very 'active' after inoculation or if thick layers or large bags are used. The latter may lead to low-oxygen conditions in parts of the substrate. Mushrooms are aerobic, meaning they need oxygen, while some undesirable bacteria thrive in anaerobic conditions. Field capacity - Content of water, on a mass or volume basis, remaining in a soil after being saturated with water and after free drainage is negligible. Described as the state achieved when one can squeeze a handful of substrate or casing material hard, only to have one or two drops emerge. Flow hood - A fan-powered and HEPA-filtered device that produces a laminar flow of contam free air. The air moves across the workspace allowing for open sterile work without the hassle and inconvience of a glove box. Flush - The sudden development of many fruiting bodies at the same time. Usually there is a resting period between flushes. Fractional sterilization - A sterilization method used to destroy bacteria and spores in preparation of grain spawn (rye, wheat, birdseed) requiring no pressure cooker. In this case, the jars fitted with a filter are boiled or steamed at 212?F (100?C) for 30 min in a covered pot, three days in a row. Between the boiling steps the jars are best kept warm, around 30?C, to allow the remaining endospores to germinate. The basic principle behind this method is that any resistant bacterial spores should germinate after the first heating and therefore be susceptible to killing during the subsequent boilings. Fruiting - The process by which the mycelium produces fruiting bodies, or mushrooms, for the purpose of spore propagation (sexual reproduction). Fruiting body - A mushroom. The part of the mushroom that grows above ground. Fruiting chamber (FC) - A enclosed space with high humidity and fresh air exchange where mushrooms may fruit under proper conditions. Fungicide - A class of pesticides used to kill fungi. Fungus - A group of organisms that includes mushrooms and molds. These organisms decompose organic material, returning nutrients to the soil.
G
G2G - See grain-to-grain transfer. Inoculation of grain by already colonized grain. Genotype - The set of genes possessed by an individual organism. Geolite - One of several brand names/varieties of clay aggregate medium (also known as LECA for light expanded clay aggregate). It is a lightweight, porous substrate with excellent aeration. Germination - The spreading of hyphae from a spore Gills - The tiny segments on the underside of the cap. This is where the spores come from. Glovebox - A glovebox is a device used to Isolate an area for work with potentially hazardous substances or materials which need to be free from direct contact with the outside environment for any reason. Most gloveboxes are small, tightly enclosed boxes having a glass panel for viewing inside and special airtight gloves which a person on the outside can use to manipulate objects inside. Glucose - See dextrose. Grain-to-grain transfer - The inoculation of grain with already-colonized grain. This procedure involves exposing uncolonized, sterilized grain, and so is prone to contamination. As such it should only be performed with a glove box, laminar flow hood, or similar device. Gypsum - Calcium sulfate, CaSO4. A greyish powder often used in spawn preparation. It prevents the clumping of the grain kernels and acts as a basic pH buffer.
H
H2O2 - See hydrogen peroxide. Hay - Grass that has been cut, left to dry in the field and then baled. It is fed to livestock through the winter when fresh grass is not available. The color of hay is greenish-grey. Not synonymous with straw. HEPA - High Efficiency Particulate Air filter. A high-efficiency filter used in flow hoods. Hydrogen peroxide - A clear aqueous solution usualy available in concentrations from 3%uFFFDo 30%uFFFDEasily decomposed into water and oxygen by enzymes like catalase, which is found in desirable mushrooms but not in many bacteria. This makes it capable of selectively destroying some competitors, and a tool sometimes used in cultivation. The mycological use of peroxide was the focus of a popular cultivation guide by Rush Wayne. Hypha(e) - Filamentous structure which exhibits apical growth and which is the developmental unit of a Mycelium.
I
In vitro - From the Latin, in glass, isolated from the living organism and artificially maintained, as in a petri dish or a jar. Incubation - The period after inoculation (preferably at a temperature optimal for mycelial growth) during which the Mycelium grows vegetatively Inoculation - Introduction of spores or spawn into substrate Isolate - A strain of a fungus brought into pure culture (i.e. isolated) from a specific environment
J
K
L
Lamellae - The gills of a mushroom LC - See liquid culture Lignin - A complex polymer that occurs in woody material of higher plants. It is highly resistant to chemical and enzymatic degradation. The white rot fungi are known for their lignin degrading capability. Limestone - See calcium carbonate. Liquid culture - A culture of mycelium suspended in a nutritious liquid, for use as an inoculant.
M
Magic mushroom - Any of a number of species of fungi containing the alkaloids psilocybin and/or psilocin. Common species are the 'liberty cap' (Psilocybe semilanceata) and Psilocybe cubensis, though there are dozens of others. Maltose - Malt sugar, used in agar formulations. Martha - Refers to a fruiting chamber based on a Martha Stewart-brand translucent vinyl closet. MEA - Malt extract agar. Metabolism - The biochemical processes that sustain a living cell or organism. Multispore - Refers to an inoculation where multiple germinations and matings occur due to the use of various spores, as in a spore solution (e.g. spore syringe) and as opposed to an isolate. Liquid cultures may sometimes be called multispore (though they contain no spores) if they were produced from a spore solution, rather than an isolate. Mycelium - The portion of the mushroom that grows underground. Plants have roots; mushrooms have mycelium. Mycelium networks can be huge. The largest living thing in the world is a single underground mycelium complex. *Mycorrhiza# - A symbiotic association between a plant root and fungal hyphae.
N
O
Overlay - A dense mycelial growth that covers the casing surface and shows little or no inclination to form pinheads. Overlay directly results from a dry casing, high levels of carbon Dioxide and/or low humidity. Oyster shells - See calcium sulfate.
P
Parasitic - Fungi that grow by taking nourishment from other living organisms. Pasteurization - Heat treatment applied to a Substrate to destroy unwanted organisms but keeping a reduced concentration of favorable ones alive. The temperature range is 60?C to 80?C(140?F-175?F). The treatment is very different from sterilization, which aims at destroying all organisms in the substrate . PDA - Potato dextrose agar. PDYA - Potato dextrose yeast agar. Peat - Unconsolidated soil material consisting largely of undecomposed, or only slightly decomposed, organic matter accumulated under conditions of excessive moisture. Used as casing ingredient in mushroom culture. Perlite - Perlite is a very light mineral, often found next to the vermiculite in gardening stores. It has millions of microscopic pores, which when it gets damp, allow it to 'breathe' lots of water into the air, aiding in humidification, which is beneficial to fruiting. Peroxidated agar - Agar made with H2O2 for the purpose of retarding contamination by bacteria and new mold spores. Not suitable for use with ungerminated mushroom spores, only live mycelium. See also: hydrogen peroxide. Petri dish - A round glass or plastic dish with a cover to observe the growth of microscopic organisms. The dishes are partly filled with sterile growth medium such as agar (or sterilized after they have been filled). Petri dishes are used to produce isolates. PF - Psylocybe Fanaticus. The original spore provider and originator of the PF-Tek, one of the original home growing techniques on which many others are based. pH - A measure to describe the acidity of a medium. pH 7 is neutral; higher means Alkaline, lower Acidic Pileus - The cap of a mushroom. Pinhead - A term to describe a very young mushroom, so-named for the pin-sized developing cap. Polyfill - A polyester fiber that resembles synthetic cotton. Found at fabric stores, Wal-Mart, arts & craft stores. Also used as a filter medium for aquariums (filter floss). Used as a jar lid filter in preparation of grain spawn and for other filtration purposes. Pressure cooker - A pot with a tight lid in which things can be cooked quickly with steam under higher pressure. The reason for it is that at 15 PSI (pound per square inch) pressure the water boils at a higher temperature (250?F, 121?C) than at ambient pressure.(212?F, 100?C). In mushroom cultivation used to thoroughly sterilize substrates and agar media. Primordium - The initial fruiting body, the stage before pinhead Psilocybin, Psilocin - Hallucinogenic organic compounds found in some mushrooms. Pure culture - An isolated culture of a micro-organism, uncontaminated with others. Pure cultures are essential to the production of spawn because it is sensitive to contamination.
R
Rhizomorph - "Root-like". An adjective used to describe the appearance of the mycelium of some mushroom strains. Rhizomorphic mycelium is taken as a sign of fast colonization and qualities desirable for fruiting. Rice cake - Many of the growing methods involve making a 'cake' of brown rice flour( BRF ), vermiculite and water, and injecting it with mushroom spores. Not a rice cake like you'd buy in a supermarket! Rye - A hardy annual cereal grass related to wheat. Lat.:Secale cereale. In mushroom cultivation rye grain is used as spawn medium. Ryegrass - A perennial grass widely cultivated for pasture and hay and as a lawn grass. Lat.:Lolium perenne. Seeds used as Substrate for P. mexicana and P. tampanensis.
S
Saprophyte - A fungus that grows by taking nourishment from dead organisms Sclerotium - A hard surfaced resting body of fungal cells resistant to unfavorable conditions,which may remain dormant for long periods of time and resume growth on the return of favorable conditions. Secondary metabolite - Product of intermediary metabolism released from a cell, such as an antibiotic. Selective medium - Medium that allows the growth of certain types of microorganisms in preference to others. For example, an antibiotic-containing medium allows the growth of only those microorganisms resistant to the antibiotic. Simmer - To cook just below or at the boiling point. Slant - A test tube with growth medium, which has been sterilized and slanted to increase the surface area Spawn - Culture of mycelium on grain, sawdust, etc., used to inoculate the final substrate, or bulk. Spawn run - The vegetative growth period of the mycelium after spawning the substrate to bulk. Species - Fundamental unit of biological taxonomy. Generally spoken, two individuals belong to the same species if they can produce fertile offspring Spore print - A collection of spores taken from a mushroom cap, often collected on sterile card stock, aluminum foil, or some other flat surface. Spore syringe - A solution of spores collected in a syringe, usually scraped from a spore print under sterile conditions. Several companies will sell you ready-to-use spore syringes for a few pounds/dollars. This site has links to, or address for, many of the most reputable of these companies. Spores - Means of sexual reproduction for mushrooms and many other fungi. Comparable to a plant seed, save that spores combined sexually with one another after germination; there are no "male" and "female" spores as with seeds and pollen or sperm and eggs, but compatability is complicated. Spores are microscopic, and any visible clump of spores is in fact a collection of many thousands or millions of spores. Stamets, Paul - The owner of Fungi Perfecti and mushroom guru. The co-author of The Mushroom Cultivator and many other helpful books. Stem - The stipe or stalk of a growing mushroom. Sterilization - Completely destroying all micro organisms present, by heat (autoclave, pressure cooker) or chemicals. Spawn substrate always has to be sterilized prior to inoculation. Stipe - The stem of a mushroom at the top of which the cap or Pileus is attached Strain - A genetic line considered to have common traits, usually identified for artificial selection by humans. Many strains have geographical names (e.g. Ecuador, Texan, Aussie), but point of natural origin is not necessarily the source of the name. Remember that strains are a human notion; vendors often differentiate between stocks that are not visibly different to everyone, but which have been perceived to have different characteristics, whether visual (e.g. the Penis Envy strain), chemical (as in strains perceived to have high potency), or behavioral (relating to the mushroom's response to environment, colonization speed, et cetera). Straw - The dried remains of fine-stemmed cereals (wheat, Rye, barley...) from which the seed has been removed in threshing. Straw has a golden color. Stroma - Dense mycelial growth without fruiting. Stroma occurs if spawn is mishandled or exposed to harmful petroleum-based fumes or chemicals. It also occurs in dry environments. Substrate - Whatever you're using to grow the mushrooms on. Different varieties of mushroom like to eat different things (rice, rye grain, straw, compost, woodchips, birdseed). Different techniques involve infecting substrates with anything from spores, to chopped-up Mycelium, to blended mushroom.
T
Tek - Short for technique. Often prefaced with something to tell you what type of tek; e.g. PF-Tek, for Psylocybe Fanaticus Technique, one of the original home growing techniques on which many others are based. Terrarium - A small enclosure or closed container in which selected living plants, fungi and sometimes small land animals, such as turtles and lizards, are kept and observed. Tissue culture - Tissue cultures are the simplest way to obtain a mycelial culture. A tissue culture is essentially a clone of a mushroom, defined as a genetic duplicate of an organism. The basic procedure is to sterilely remove a piece of the mushroom cap or stem, and place it on an agar plate. After a week to ten days, Mycelium grows from the tissue and colonizes the agar. Great care should be taken to select a fruiting body of the highest quality, size, color, shape or any highly desired characteristic. TiT - "Tub in Tub", refers to an incubator consisting of 2 plastic tubs and an aquarium heater. Trichoderma - A common green mold. Trip - What happens when you eat the finished product, if you are cultivating hallucinogenic varieties. With psilocybes, a trip tends to last from three to six hours. May range from mild visual effects and lightly enhanced perceptions, to a totally altered state of consciousness. Generally, this can be controlled to some degree by mindset, setting and dosage. Read some of the trip reports to get an idea of what other people have experienced before experiencing hallucinogens. Please always remember, although many of the effects seem to be experienced by many different people, you're going to have your trip, not someone else's. Tyndallization - See fractional sterilization
U
Umbonate - Used to describe a cap with a raised central area above the point where the stipe meets the pileus
V
Veil - When a mushroom is growing, the edges of the cap are joined to the stem. As the mushroom grows larger, the cap spreads and the edges tear away, often leaving a very thin veil of material hanging from the stem. Vermiculite - A highly absorbent material made from puffed mica. Used in rice cakes to hold water, and to stop the cake being too sticky. The mycelium likes room to breathe and grow.
W
WBS - Wild bird seed. Millet-based birdseed; used as spawn and Substrate in mushroom cultivation.
Z
Zonate - Marked with concentric bands of colour. Refers to the appearance of mycelium of some mushroom species on agar, for instance P. mexicana.
Given a population (colony) of bacteria, all offsprings are essentially clones of their parents, how will they speciate? Is it still meaningful to use terms like sympatric or allopatric speciation? Without sexual reproduction, gene flow occurs only in instances of bacterial transformation or conjugation, but as far as I know these are not strictly intraspecific. So at what point is bacterial speciation complete?
Organisms of many species are specialized into male and female varieties, each known as a sex.[1] Sexual reproduction involves the combining and mixing of genetic traits: specialized cells known as gametes combine to form offspring that inherit traits from each parent. Gametes can be identical in form and function (known as isogamy), but in many cases an asymmetry has evolved such that two sex-specific types of gametes (heterogametes) exist (known as anisogamy). By definition, male gametes are small, motile, and optimized to transport their genetic information over a distance, while female gametes are large, non-motile and contain the nutrients necessary for the early development of the young organism. Among humans and other mammals, males typically carry XY chromosomes, whereas females typically carry XX chromosomes, which are a part of the XY sex-determination system. The gametes produced by an organism determine its sex: males produce male gametes (spermatozoa, or sperm, in animals; pollen in plants) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic. Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience. Contents [hide] 1 Evolution 2 Sexual reproduction 2.1 Animals 2.2 Plants 2.3 Fungi 3 Sex determination 3.1 Genetic 3.2 Nongenetic 4 Sexual dimorphism 5 See also 6 References 7 Further reading 8 External links Evolution Main article: Evolution of sexual reproduction It is considered that sexual reproduction in eukaryotes first appeared about a billion years ago and evolved within ancestral single-celled eukaryotes.[2] The reason for the initial evolution of sex, and the reason(s) it has survived to the present, are still matters of debate. Some of the many plausible theories for the appearance of sexual reproduction include: the creation of variation among offspring, to spread advantageous traits, the beneficial removal of disadvantageous traits, and that sex evolved as an adaptation for repairing damage in DNA. (See the evolution of sexual reproduction.) While there are a number of theories, there are two main alternative views on the evolutionary origin and adaptive significance of sex. The first view assumes that sexual reproduction is a process specific to eukaryotes, organisms whose cells contain a nucleus and mitochondria. In addition to sex in animals, plants, and fungi, there are other eukaryotes (e.g. the malaria parasite) that also engage in sexual reproduction. On this first view, the adaptive advantage that maintains sexual reproduction (in competition with asexual modes of reproduction) is the benefit of generating genetic variation among progeny. Furthermore, on this view, sex originated in a eukaryotic lineage. The earliest eukaryotes and the bacterial ancestors from which they arose are assumed to have lacked sex. For instance, some bacteria use conjugation to transfer genetic material between cells; and while not the same as sexual reproduction, this also results in the mixture of genetic traits. The reason that bacterial conjugation is not the same as sexual reproduction is that the numerous genes necessary for conjugation are not located on the bacterial chromosome, but on small circular DNA self-replicating parasitic elements called conjugative plasmids. Thus, conjugation arises from an adaptation of parasitic DNA for its own transmission.[3] The second alternative view on the evolutionary origin and adaptive significance of sex is that sex existed in early bacteria as the process of natural transformation, a well studied DNA exchange process still in existence in many present day bacterial species (see Transformation (genetics)). Transformation involves the transfer of DNA from a donor to a recipient bacterium. Recipient bacteria must first enter a special physiological state, termed competence, to receive donor DNA (see Natural competence). The numerous genes necessary for establishment of competence are located on the bacterial chromosome itself. Thus the process of transformation is likely beneficial to bacteria, and can be regarded as a simple form of sex. In general, competence is induced under stressful conditions, such as nutrient limitation and exposure to DNA damaging agents, as reviewed by a number of authors.[4][5][6] Sex, on this view, was present in the earliest single-celled eukaryotes because they were descended from ancestral bacteria capable of transformation. Sex was maintained as an adaptation for repairing DNA damage (see Evolution of sexual reproduction). In particular, meiosis the key stage of the sexual cycle of eukaryotes, in which genetic information derived from different individuals (parents) recombines, was likely derived from the analogous, but simpler, genetic information exchange and DNA repair process that occurs during transformation in bacteria[7][8][9][10] (and also see Meiosis, section: Origin and function of meiosis). Thus, by this view, sex appears to have evolved in bacteria as a way of repairing DNA damages induced by environmental stresses, was maintained through the prokaryote/eukaryote boundary, and continued to evolve in higher multicellular eukaryotes, in part, as a DNA repair process. What is considered defining of sexual reproduction in eukaryotes is the difference between the gametes and the binary nature of fertilization. Multiplicity of gamete types within a species would still be considered a form of sexual reproduction. However, no third gamete is known in multicellular animals.[11][12][13] While the evolution of sex itself dates to the prokaryote or early eukaryote stage, the origin of chromosomal sex determination may have been fairly early in eukaryotes. The ZW sex-determination system is shared by birds, some fish and some crustaceans. Most mammals, but also some insects (Drosophila) and plants (Ginkgo) use XY sex-determination. X0 sex-determination is found in certain insects. No genes are shared between the avian ZW and mammal XY chromosomes,[14] and from a comparison between chicken and human, the Z chromosome appeared similar to the autosomal chromosome 9 in human, rather than X or Y, suggesting that the ZW and XY sex-determination systems do not share an origin, but that the sex chromosomes are derived from autosomal chromosomes of the common ancestor of birds and mammals. A paper from 2004 compared the chicken Z chromosome with platypus X chromosomes and suggested that the two systems are related.[15] Sexual reproduction Main article: Sexual reproduction Further information: Isogamy and Anisogamy The life cycle of sexually reproducing organisms cycles through haploid and diploid stages Sexual reproduction in eukaryotes is a process whereby organisms form offspring that combine genetic traits from both parents. Chromosomes are passed on from one generation to the next in this process. Each cell in the offspring has half the chromosomes of the mother and half of the father.[16] Genetic traits are contained within the deoxyribonucleic acid (DNA) of chromosomes—by combining one of each type of chromosomes from each parent, an organism is formed containing a doubled set of chromosomes. This double-chromosome stage is called "diploid", while the single-chromosome stage is "haploid". Diploid organisms can, in turn, form haploid cells (gametes) that randomly contain one of each of the chromosome pairs, via meiosis.[17] Meiosis also involves a stage of chromosomal crossover, in which regions of DNA are exchanged between matched types of chromosomes, to form a new pair of mixed chromosomes. Crossing over and fertilization (the recombining of single sets of chromosomes to make a new diploid) result in the new organism containing a different set of genetic traits from either parent. In many organisms, the haploid stage has been reduced to just gametes specialized to recombine and form a new diploid organism; in others, the gametes are capable of undergoing cell division to produce multicellular haploid organisms. In either case, gametes may be externally similar, particularly in size (isogamy), or may have evolved an asymmetry such that the gametes are different in size and other aspects (anisogamy).[18] By convention, the larger gamete (called an ovum, or egg cell) is considered female, while the smaller gamete (called a spermatozoon, or sperm cell) is considered male. An individual that produces exclusively large gametes is female, and one that produces exclusively small gametes is male. An individual that produces both types of gametes is a hermaphrodite; in some cases hermaphrodites are able to self-fertilize and produce offspring on their own, without a second organism.[19] Animals Main article: Sexual reproduction in animals Hoverflies engaging in sexual intercourse Most sexually reproducing animals spend their lives as diploid organisms, with the haploid stage reduced to single cell gametes.[20] The gametes of animals have male and female forms—spermatozoa and egg cells. These gametes combine to form embryos which develop into a new organism. The male gamete, a spermatozoon (produced within a testicle), is a small cell containing a single long flagellum which propels it.[21] Spermatozoa are extremely reduced cells, lacking many cellular components that would be necessary for embryonic development. They are specialized for motility, seeking out an egg cell and fusing with it in a process called fertilization. Female gametes are egg cells (produced within ovaries), large immobile cells that contain the nutrients and cellular components necessary for a developing embryo.[22] Egg cells are often associated with other cells which support the development of the embryo, forming an egg. In mammals, the fertilized embryo instead develops within the female, receiving nutrition directly from its mother. Animals are usually mobile and seek out a partner of the opposite sex for mating. Animals which live in the water can mate using external fertilization, where the eggs and sperm are released into and combine within the surrounding water.[23] Most animals that live outside of water, however, must transfer sperm from male to female to achieve internal fertilization. In most birds, both excretion and reproduction is done through a single posterior opening, called the cloaca—male and female birds touch cloaca to transfer sperm, a process called "cloacal kissing".[24] In many other terrestrial animals, males use specialized sex organs to assist the transport of sperm—these male sex organs are called intromittent organs. In humans and other mammals this male organ is the penis, which enters the female reproductive tract (called the vagina) to achieve insemination—a process called sexual intercourse. The penis contains a tube through which semen (a fluid containing sperm) travels. In female mammals the vagina connects with the uterus, an organ which directly supports the development of a fertilized embryo within (a process called gestation). Because of their motility, animal sexual behavior can involve coercive sex. Traumatic insemination, for example, is used by some insect species to inseminate females through a wound in the abdominal cavity – a process detrimental to the female's health. Plants Flowers are the sexual organs of flowering plants, usually containing both male and female parts. Main article: Plant reproduction Like animals, plants have developed specialized male and female gametes.[25] Within most familiar plants, male gametes are contained within hard coats, forming pollen. The female gametes of plants are contained within ovules; once fertilized by pollen these form seeds which, like eggs, contain the nutrients necessary for the development of the embryonic plant. Pinus nigra cone.jpg Pine cones, immature male.jpg Female (left) and male (right) cones are the sex organs of pines and other conifers. Many plants have flowers and these are the sexual organs of those plants. Flowers are usually hermaphroditic, producing both male and female gametes. The female parts, in the center of a flower, are the carpels—one or more of these may be merged to form a single pistil. Within carpels are ovules which develop into seeds after fertilization. The male parts of the flower are the stamens: these long filamentous organs are arranged between the pistil and the petals and produce pollen at their tips. When a pollen grain lands upon the top of a carpel, the tissues of the plant react to transport the grain down into the carpel to merge with an ovule, eventually forming seeds. In pines and other conifers the sex organs are conifer cones and have male and female forms. The more familiar female cones are typically more durable, containing ovules within them. Male cones are smaller and produce pollen which is transported by wind to land in female cones. As with flowers, seeds form within the female cone after pollination. Because plants are immobile, they depend upon passive methods for transporting pollen grains to other plants. Many plants, including conifers and grasses, produce lightweight pollen which is carried by wind to neighboring plants. Other plants have heavier, sticky pollen that is specialized for transportation by insects. The plants attract these insects with nectar-containing flowers. Insects transport the pollen as they move to other flowers, which also contain female reproductive organs, resulting in pollination. Fungi Main article: Mating in fungi Mushrooms are produced as part of fungal sexual reproduction Most fungi reproduce sexually, having both a haploid and diploid stage in their life cycles. These fungi are typically isogamous, lacking male and female specialization: haploid fungi grow into contact with each other and then fuse their cells. In some of these cases the fusion is asymmetric, and the cell which donates only a nucleus (and not accompanying cellular material) could arguably be considered "male".[26] Some fungi, including baker's yeast, have mating types that create a duality similar to male and female roles. Yeast with the same mating type will not fuse with each other to form diploid cells, only with yeast carrying the other mating type.[27] Fungi produce mushrooms as part of their sexual reproduction. Within the mushroom diploid cells are formed, later dividing into haploid spores—the height of the mushroom aids the dispersal of these sexually produced offspring. Sex determination Main article: Sex-determination system Sex helps the spread of advantageous traits through recombination. The diagrams compare evolution of allele frequency in a sexual population (top) and an asexual population (bottom). The vertical axis shows frequency and the horizontal axis shows time. The alleles a/A and b/B occur at random. The advantageous alleles A and B, arising independently, can be rapidly combined by sexual reproduction into the most advantageous combination AB. Asexual reproduction takes longer to achieve this combination, because it can only produce AB if A arises in an individual which already has B, or vice versa. The most basic sexual system is one in which all organisms are hermaphrodites, producing both male and female gametes—this is true of some animals (e.g. snails) and the majority of flowering plants.[28] In many cases, however, specialization of sex has evolved such that some organisms produce only male or only female gametes. The biological cause for an organism developing into one sex or the other is called sex determination. In the majority of species with sex specialization, organisms are either male (producing only male gametes) or female (producing only female gametes). Exceptions are common—for example, in the roundworm C. elegans the two sexes are hermaphrodite and male (a system called androdioecy). Sometimes an organism's development is intermediate between male and female, a condition called intersex. Sometimes intersex individuals are called "hermaphrodite"; but, unlike biological hermaphrodites, intersex individuals are unusual cases and are not typically fertile in both male and female aspects. Genetic Like humans and other mammals, the common fruit fly has an XY sex-determination system. In genetic sex-determination systems, an organism's sex is determined by the genome it inherits. Genetic sex-determination usually depends on asymmetrically inherited sex chromosomes which carry genetic features that influence development; sex may be determined either by the presence of a sex chromosome or by how many the organism has. Genetic sex-determination, because it is determined by chromosome assortment, usually results in a 1:1 ratio of male and female offspring. Humans and other mammals have an XY sex-determination system: the Y chromosome carries factors responsible for triggering male development. The default sex, in the absence of a Y chromosome, is female. Thus, XX mammals are female and XY are male. XY sex determination is found in other organisms, including the common fruit fly and some plants.[28] In some cases, including in the fruit fly, it is the number of X chromosomes that determines sex rather than the presence of a Y chromosome (see below). In birds, which have a ZW sex-determination system, the opposite is true: the W chromosome carries factors responsible for female development, and default development is male.[29] In this case ZZ individuals are male and ZW are female. The majority of butterflies and moths also have a ZW sex-determination system. In both XY and ZW sex determination systems, the sex chromosome carrying the critical factors is often significantly smaller, carrying little more than the genes necessary for triggering the development of a given sex.[30] Many insects use a sex determination system based on the number of sex chromosomes. This is called X0 sex-determination—the 0 indicates the absence of the sex chromosome. All other chromosomes in these organisms are diploid, but organisms may inherit one or two X chromosomes. In field crickets, for example, insects with a single X chromosome develop as male, while those with two develop as female.[31] In the nematode C. elegans most worms are self-fertilizing XX hermaphrodites, but occasionally abnormalities in chromosome inheritance regularly give rise to individuals with only one X chromosome—these X0 individuals are fertile males (and half their offspring are male).[32] Other insects, including honey bees and ants, use a haplodiploid sex-determination system.[33] In this case diploid individuals are generally female, and haploid individuals (which develop from unfertilized eggs) are male. This sex-determination system results in highly biased sex ratios, as the sex of offspring is determined by fertilization rather than the assortment of chromosomes during meiosis. Nongenetic Clownfish are initially male; the largest fish in a group becomes female For many species, sex is not determined by inherited traits, but instead by environmental factors experienced during development or later in life. Many reptiles have temperature-dependent sex determination: the temperature embryos experience during their development determines the sex of the organism. In some turtles, for example, males are produced at lower incubation temperatures than females; this difference in critical temperatures can be as little as 1–2 °C. Many fish change sex over the course of their lifespan, a phenomenon called sequential hermaphroditism. In clownfish, smaller fish are male, and the dominant and largest fish in a group becomes female. In many wrasses the opposite is true—most fish are initially female and become male when they reach a certain size. Sequential hermaphrodites may produce both types of gametes over the course of their lifetime, but at any given point they are either female or male. In some ferns the default sex is hermaphrodite, but ferns which grow in soil that has previously supported hermaphrodites are influenced by residual hormones to instead develop as male.[34] Sexual dimorphism Main article: Sexual dimorphism Common Pheasants are sexually dimorphic in both size and appearance. Many animals and some plants have differences between the male and female sexes in size and appearance, a phenomenon called sexual dimorphism. Sex differences in humans include, generally, a larger size and more body hair in men; women have breasts, wider hips, and a higher body fat percentage. In other species, the differences may be more extreme, such as differences in coloration or bodyweight. In humans, biological sex is determined by five factors present at birth: the presence or absence of a Y chromosome, the type of gonads, the sex hormones, the internal reproductive anatomy (such as the uterus in females), and the external genitalia.[35] Sexual dimorphisms in animals are often associated with sexual selection – the competition between individuals of one sex to mate with the opposite sex.[36] Antlers in male deer, for example, are used in combat between males to win reproductive access to female deer. In many cases the male of a species is larger than the female. Mammal species with extreme sexual size dimorphism tend to have highly polygynous mating systems—presumably due to selection for success in competition with other males—such as the elephant seals. Other examples demonstrate that it is the preference of females that drive sexual dimorphism, such as in the case of the stalk-eyed fly.[37] Other animals, including most insects and many fish, have larger females. This may be associated with the cost of producing egg cells, which requires more nutrition than producing sperm—larger females are able to produce more eggs.[38] For example, female southern black widow spiders are typically twice as long as the males.[39] Occasionally this dimorphism is extreme, with males reduced to living as parasites dependent on the female, such as in the anglerfish. Some plant species also exhibit dimorphism in which the females are significantly larger than the males, such as in the moss Dicranum[40] and the liverwort Sphaerocarpos.[41] There is some evidence that, in these genera, the dimorphism may be tied to a sex chromosome,[41][42] or to chemical signalling from females.[43] In birds, males often have a more colourful appearance and may have features (like the long tail of male peacocks) that would seem to put the organism at a disadvantage (e.g. bright colors would seem to make a bird more visible to predators). One proposed explanation for this is the handicap principle.[44] This hypothesis says that, by demonstrating he can survive with such handicaps, the male is advertising his genetic fitness to females—traits that will benefit daughters as well, who will not be encumbered with such handicaps. See also Sex and gender distinction References Jump up ^ sex. CollinsDictionary.com. Collins English Dictionary – Complete & Unabridged 11th Edition. Retrieved 3 December 2012. Jump up ^ "Book Review for Life: A Natural History of the First Four Billion Years of Life on Earth". Jupiter Scientific. Retrieved 2008-04-07. Jump up ^ Krebs JE, Goldstein ES and Kilpatrick ST (2011). Lewin's GENES X, Jones and Bartlett Publishers, Boston, pp. 289–292, ISBN 0763766321. Jump up ^ Michod, R. E.; Wojciechowski, M. F.; Hoelzer, M. A. (1988). "DNA repair and the evolution of transformation in the bacterium Bacillus subtilis". Genetics 118 (1): 31–39. PMC 1203263. PMID 8608929. edit Jump up ^ Dorer, M. S.; Fero, J.; Salama, N. R. (2010). "DNA Damage Triggers Genetic Exchange in Helicobacter pylori". In Blanke, Steven R. PLoS Pathogens 6 (7): e1001026. doi:10.1371/journal.ppat.1001026. PMC 2912397. PMID 20686662. edit Jump up ^ Charpentier, X.; Kay, E.; Schneider, D.; Shuman, H. A. (2010). "Antibiotics and UV Radiation Induce Competence for Natural Transformation in Legionella pneumophila". Journal of Bacteriology 193 (5): 1114–1121. doi:10.1128/JB.01146-10. PMC 3067580. PMID 21169481. edit Jump up ^ Michod, R. E.; Bernstein, H.; Nedelcu, A. M. (2008). "Adaptive value of sex in microbial pathogens". Infection, Genetics and Evolution 8 (3): 267–285. doi:10.1016/j.meegid.2008.01.002. PMID 18295550. edit http://www.hummingbirds.arizona.edu/Faculty/Michod/Downloads/IGE%20review%20sex.pdf Jump up ^ Bernstein, H.; Bernstein, C. (2010). "Evolutionary Origin of Recombination during Meiosis". BioScience 60 (7): 498. doi:10.1525/bio.2010.60.7.5. edit Jump up ^ Harris Bernstein H, Bernstein C, Michod RE. (2011) Meiosis as an Evolutionary Adaptation for DNA Repair. Chapter 19, pp. 357–382, in "DNA Repair", Inna Kruman (ed.). Open access publisher Intech. ISBN 978-953-307-697-3 doi:10.5772/25117 Jump up ^ Bernstein H, Bernstein C, Michod RE. (2012) "DNA Repair as the Primary Adaptive Function of Sex in Bacteria and Eukaryotes". Chapter 1, pp. 1–50, in DNA Repair: New Research, S. Kimura and Shimizu S. (eds.) Nova Sci. Publ., Hauppauge, N.Y. ISBN 978-1-62100-756-2 https://www.novapublishers.com/catalog/product_info.php?products_id=31918 Jump up ^ Schaffer, Amanda (updated September 27, 2007) "Pas de Deux: Why Are There Only Two Sexes?", Slate. Jump up ^ Hurst, Laurence D. (1996). "Why are There Only Two Sexes?". Proceedings: Biological Sciences 263 (1369): 415–422. doi:10.1098/rspb.1996.0063. JSTOR 50723. Jump up ^ Haag ES (2007). "Why two sexes? Sex determination in multicellular organisms and protistan mating types". Seminars in Cell and Developmental Biology 18 (3): 348–9. doi:10.1016/j.semcdb.2007.05.009. PMID 17644371. Jump up ^ Stiglec R, Ezaz T, Graves JA (2007). "A new look at the evolution of avian sex chromosomes". Cytogenet. Genome Res. 117 (1–4): 103–109. doi:10.1159/000103170. PMID 17675850. Jump up ^ Grützner, F.; Rens, W., Tsend-Ayush, E., El-Mogharbel, N., O'Brien, P.C.M., Jones, R.C., Ferguson-Smith, M.A. and Marshall, J.A. (2004). "In the platypus a meiotic chain of ten sex chromosomes shares genes with the bird Z and mammal X chromosomes". Nature 432 (7019): 913–917. doi:10.1038/nature03021. PMID 15502814. Jump up ^ Alberts et al. (2002), U.S. National Institutes of Health, "V. 20. The Benefits of Sex". Jump up ^ Alberts et al. (2002), "V. 20. Meiosis", U.S. NIH, V. 20. Meiosis. Jump up ^ Gilbert (2000), "1.2. Multicellularity: Evolution of Differentiation". 1.2.Mul, NIH. Jump up ^ Alberts et al. (2002), "V. 21. Caenorhabditis Elegans: Development as Indiv. Cell", U.S. NIH, V. 21. Caenorhabditis. Jump up ^ Alberts et al. (2002), "3. Mendelian genetics in eukaryotic life cycles", U.S. NIH, 3. Mendelian/eukaryotic. Jump up ^ Alberts et al. (2002), "V.20. Sperm", U.S. NIH, V.20. Sperm. Jump up ^ Alberts et al. (2002), "V.20. Eggs", U.S. NIH, V.20. Eggs. Jump up ^ Alberts et al. (2002), "V.20. Fertilization", U.S. NIH, V.20. Fertilization. Jump up ^ Ritchison G. "Avian Reproduction". Eastern Kentucky University. Retrieved 2008-04-03. Jump up ^ Gilbert (2000), "4.20. Gamete Production in Angiosperms", U.S. NIH, 4.20. Gamete/Angio.. Jump up ^ Nick Lane (2005). Power, Sex, Suicide: Mitochondria and the Meaning of Life. Oxford University Press. pp. 236–237. ISBN 0-19-280481-2. Jump up ^ Matthew P Scott, Paul Matsudaira, Harvey Lodish, James Darnell, Lawrence Zipursky, Chris A Kaiser, Arnold Berk, Monty Krieger (2000). Molecular Cell Biology (Fourth ed.). WH Freeman and Co. ISBN 0-7167-4366-3.14.1. Cell-Type Specification and Mating-Type Conversion in Yeast ^ Jump up to: a b Dellaporta SL, Calderon-Urrea A (1993). "Sex Determination in Flowering Plants". The Plant Cell (American Society of Plant Biologists) 5 (10): 1241–1251. doi:10.2307/3869777. JSTOR 3869777. PMC 160357. PMID 8281039. Jump up ^ Smith CA, Katza M, Sinclair AH (2003). "DMRT1 Is Upregulated in the Gonads During Female-to-Male Sex Reversal in ZW Chicken Embryos". Biology of Reproduction 68 (2): 560–570. doi:10.1095/biolreprod.102.007294. PMID 12533420. Jump up ^ "Evolution of the Y Chromosome". Annenberg Media. Retrieved 2008-04-01. Jump up ^ Yoshimura A (2005). "Karyotypes of two American field crickets: Gryllus rubens and Gryllus sp. (Orthoptera: Gryllidae)". Entomological Science 8 (3): 219–222. doi:10.1111/j.1479-8298.2005.00118.x. Jump up ^ Riddle DL, Blumenthal T, Meyer BJ, Priess JR (1997). C. Elegans II. Cold Spring Harbor Laboratory Press. ISBN 0-87969-532-3. 9.II. Sexual Dimorphism Jump up ^ Charlesworth B (2003). "Sex Determination in the Honeybee". Cell 114 (4): 397–398. doi:10.1016/S0092-8674(03)00610-X. PMID 12941267. Jump up ^ Tanurdzic M and Banks JA (2004). "Sex-Determining Mechanisms in Land Plants". The Plant Cell 16 (Suppl): S61–S71. doi:10.1105/tpc.016667. PMC 2643385. PMID 15084718. Jump up ^ Knox, David; Schacht, Caroline. Choices in Relationships: An Introduction to Marriage and the Family. 11 ed. Cengage Learning; 2011-10-10 [cited 17 June 2013]. ISBN 9781111833220. p. 64–66. Jump up ^ Darwin C (1871). The Descent of Man. Murray, London. ISBN 0-8014-2085-7. Jump up ^ Wilkinson G.S., Reillo P.R. (22 January 1994). "Female choice response to artificial selection on an exaggerated male trait in a stalk-eyed fly". Proceedings of the Royal Society B 225 (1342): 1–6. doi:10.1098/rspb.1994.0001. Jump up ^ Stuart-Smith J, Swain R, Stuart-Smith R, Wapstra E (2007). "Is fecundity the ultimate cause of female-biased size dimorphism in a dragon lizard?". Journal of Zoology 273 (3): 266–272. doi:10.1111/j.1469-7998.2007.00324.x. Jump up ^ "Southern black widow spider". Insects.tamu.edu. Retrieved 2012-08-08. Jump up ^ Shaw, A. Jonathan (2000). "Population ecology, population genetics, and microevolution". In A. Jonathan Shaw & Bernard Goffinet (eds.). Bryophyte Biology. Cambridge: Cambridge University Press. pp. 379–380. ISBN 0-521-66097-1. ^ Jump up to: a b Schuster, Rudolf M. (1984). "Comparative Anatomy and Morphology of the Hepaticae". New Manual of Bryology 2. Nichinan, Miyazaki, Japan: The Hattori botanical Laboratory. p. 891. Jump up ^ Crum, Howard A.; Anderson, Lewis E. (1980). Mosses of Eastern North America 1. New York: Columbia University Press. p. 196. ISBN 0-231-04516-6. Jump up ^ Briggs, D. A. (1965). "Experimental taxonomy of some British species of genus Dicranum". New Phytologist 64 (3): 366–386. doi:10.1111/j.1469-8137.1965.tb07546.x. Jump up ^ Zahavi, A. and Zahavi, A. (1997) The handicap principle: a missing piece of Darwin's puzzle. Oxford University Press. Oxford. ISBN 0-19-510035-2 Further reading Arnqvist, G. & Rowe, L. (2005) Sexual conflict. Princeton University Press, Princeton. ISBN 0-691-12217-2 Alberts B, Johnson A, Lewis J, Raff M, Roberts K, and Walter P (2002). Molecular Biology of the Cell (4th ed.). New York: Garland Science. ISBN 0-8153-3218-1. Ellis, Havelock (1933). Psychology of Sex. London: W. Heinemann Medical Books. xii, 322 p. N.B.: One of many books by this pioneering authority on aspects of human sexuality. Gilbert SF (2000). Developmental Biology (6th ed.). Sinauer Associates, Inc. ISBN 0-87893-243-7. Maynard-Smith, J. The Evolution of Sex. Cambridge University Press, 1978. External links Find more about Sex at Wikipedia's sister projects Definitions and translations from Wiktionary Media from Commons Quotations from Wikiquote Source texts from Wikisource Textbooks from Wikibooks Learning resources from Wikiversity Wikipedia book Sex at Wikipedia books Human Sexual Differentiation by P. C. 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Bacterial Sexual Reproduction. After viewing this video, you should be able to define bacterial conjugation as the process used by cells to reproduce. Essentially, conjugation refers to the process through which bacteria exchange genetic material. This process is often regarded as the bacterial equivalent of sexual reproduction/mating given that it involves an exchange of genetic material between two cells (recipient and donor). Conjugation: It was first reported by Lederberg and Tatum (1946) in E.coli bacteria. Cell to cell union occurs between two bacterial cells and genetic material (DNA) of one bacterial cell goes to another cell lengthwise through conjugation tube which is formed by sex pili. More about Conjugation in bacteria is a process in which plasmids are transferred by themselves alone or along with other DNA element from one cell to another cell through conjugation tube. Conjugation occur by physical contact between cells. Conjugation, in biology, sexual process in which two lower organisms of the same species, such as bacteria, protozoans, and some algae and fungi, exchange nuclear material during a temporary union (e.g., ciliated protozoans), completely transfer one organism’s contents to the other organism (bacteria and some algae), or fuse together to form one organism (most bacteria and fungi and some algae). Within a given population of organisms, the various forms that may engage in conjugation are The bacterial chromosome now undergoes replication. A copy of the freed end of bacterial chromosome (end distal to F + factor, also called zero end) passes into the recipient cell through the conjugation tube. Fertility factor is the last to do so. Generally whole of bacterial chromosome does not pass into recipient cell. Conjugation. How Do Bacteria Reproduce? As we have already discussed, bacteria reproduce through both asexual and sexual means. IN this section we will learn about these different modes of reproduction in bacteria. Asexual Reproduction in Bacteria. Binary Fission: In binary fission, a single bacterial cell divides into two daughter cells. At first, the bacterial cell reaches critical mass in its form and cell components. Conjugation - Bacterial Reproduction | Home | | Pharmaceutical Microbiology | Chapter: Pharmaceutical Microbiology : Bacteria. Conjugation is thought to have evolved through transduction, and relates to the generation of defective viral DNA. This can be transcribed to produce singular viral elements, which cannot assemble or lyse the host cell. Conjugation is not truly sexual reproduction. However, it is analogous to sexual reproduction in that it gives the same type of fitness advantage as sexual reproduction. Conjugation results in the recombination of genes, which is occasionally help... Conjugation is a process of genetic recombination that occurs between two organisms (such as bacteria) in addition to asexual reproduction. Conjugation only occurs between cells of different mating types. In bacteria, cells designated F+ and F-lie close together, and a narrow bridge of cytoplasm forms between them.
Conjugation In Bacteria lecture For Biology, Zoology, Botany Classes compare budding with binary fission* Both create identical copies (generally)* Both occur much more rapidly than sexual reproduction Conjugation in Ciliated Protozoa! Extreme HD! - Duration: 1:55. ... Markiplier Recommended for you. 13:50. Growth and Reproduction in Bacteria - Duration: 13:00. Iken Edu 70,648 views. https://Biology-Forums.com Ask questions here: https://Biology-Forums.com/index.php?board=3.0 Facebook: https://facebook.com/StudyForcePS/ Instagram: ht... Hello, Dosto is video m hm log bat krege Sexual Reproduction in Bacteria ki, is video m bacteria k sexual reproduction k bare m btaya gya hai, bacteria m sex... This video discuss about Conjugation in bacteria. It is part 3 of reproductionTransduction will be posted soonStudy wellPlease subscribe, share and like#bota... Edited by Dr.Osama Ma3rof Teaching Assistant in the microbiology departmentFaculty of pharmacy Facebook profile : www.facebook.com/Dr.Osama.MaaroufFacebook g... # EASSY NOTESBacterial Conjugation, transformation &transduction For bsc students Recombinant biotechnology-~-~~-~~~-~~-~-Please watch: "Equisetium life cycl... Study video for NBEO Part 1 Microbiology Section