texts:
I don't know much about biology. I just like watching David Attenborough videos and this made me curious.

I just watched this video about breeding Southern Right Whales, and these two quotes puzzled me:

Quote 1 occurs at 1:54

  "The males barge and jostle one another to reach her"

Quote 2 occurs at 3:51

  "One coupling can flush out whatever preceded it, so it may not be the
  first male who succeeded in copulating who becomes a father it
  (will/would?) be the last."

Quote 1 suggests my first assumption.

Males compete to be the first to mate with a female

Quote 2 suggests that a male's chance of being a father is decreased each time a subsequent male copulates with the female. This leads me to my next assumption.

The last male to mate with the female has the best chance of being the father

Beyond what was said in the video, I just have a general assumption that the healthiest male (best genes) will mate first because he's faster, stronger, etc. So here is my third assumption.

The last male to mate is the male carrying the worst genes.

All together, this seems pretty bad for the species. I mean, if the worst genes are the ones most likely to get passed down, wouldn't that make the species evolve in a bad direction? So here is my conclusion.

The breeding habits of southern right whales are bad for the species.

Is this true? If so, does this occur in other species, and does it have a name? If not, where did I go wrong with my logic?

Thanks.


texts: How exactly does the countercurrent multiplier mechanism work in formation of urine in the body? I am unable to find a satisfactory answer to this.


texts: Do animals with their eyes ~180 degrees apart have depth perception?

texts: Lots of animals have their eyes more on the side of their head, like an octopus or a parrot. Are animals with eyes more on the side able to tell the depth of objects at different distances? It seems like the line of sight in each eye wouldn't be able to cross to a singular point to triangulate distance.


texts:
I was asking myself this weird question.

When you get up or stand up too fast, sometimes, you see something like a dark veil, and you aren't able to see anything distinctly for 2 or 3 seconds, then it come back to normal.

Do you know what causes this weird phenomenon (biologically speaking), or am i the only weird person feeling this sometimes?


texts: Do macrophages get nutritional value from the pathogens that they eat?

texts:
X-posted on reddit AskScience here.

I know that macrophages engulf foreign bodies and transport them to various waste excretion pathways (sorry if the terminology is wrong), and if the foreign bodies are cellular in nature, they get trapped in phagolysosomes and get digested by enzymes.

Does the macrophage get any "nutrition" by destroying the cells, the same way that a person would if those same cells were to pass through their digestive system? Is there any chemical energy produced by the catalysis that the macrophage then uses, e.g. pyruvate for its mitochondria? Or scavenged cellular components that it can use to build its own cytoskeleton?


texts: "Bacteria don't have membrane-bound organelles." Are sulfur bacteria or Cyanobacteria exceptions?

texts:
Can bacteria have membrane-bound organelles?
I read this many textbooks:

Bacteria cells are simple cells that do not contain a nucleus or other membrane-bound organelles. However, they do contain other cellular structures that aid with their life processes.

Or here:

Prokaryotic cells (Figure below) are usually smaller and simpler than eukaryotic cells. They do not have a nucleus or other membrane-bound organelles. In prokaryotic cells, the DNA, or genetic material, forms a single large circle that coils up on itself

Are sulfur bacteria or Cyanobacteria exceptions?
Sulfur bacteria because they have big vacuoles. (Vacuoles do have membrane, don't they? Or maybe something is different about prokaryotic vacuoles that I don't know?)

A vacuole is a membrane-bound organelle which is present in plant and fungal cells and some protist, animal and bacterial cells. (1)

And
Cyanobacteria because they have gas vesicles. (These vesicles are membranous, aren't they?)

(1): Schulz-Vogt HN (2006). "Vacuoles". Inclusions in Prokaryotes. Microbiology Monographs. 1. pp. 295–298.


texts: What does this Barbary Macaque facial expression mean?

texts: A girl pretended having a piece of food in her hand and pointed it to a Barbary Macaque in Gibraltar. As a response he made this facial expression to her. What does this mean?


texts: How does the glycocalyx of cells attach together if they are negatively charged?

texts:
Context

Thus, the entire outside surface of the cell has a loose carbohydrate coat called the glycocalyx.
The carbohydrate moieties attached to the outer surface of the cell has several important functions:

Many of them have a negative electrical charge, which gives most cells an overall negative surface charge that repels other negatively charged objects.

The glycocalyx of some cells attaches to the glycocalyx of other cells, thus attaching cells to one another.

[Guyton and Hall, Textbook of Medical Physiology, 2nd South Asia Edition ( w.r.t 13e)]
Here, two contrasting statements are written. They seem to differ in the context. Actually, I tried searching for more about glycocalyx and saw the same written in many places without explanation. Or is it a concept too simple to be explained. I am unable to understand that how the cells can be attached, if both of them are negatively charged.


texts:
There's this fascinating "kitchen experiment". Take a "brick" of baker's yeast (not dry yeast), and a couple teaspoons of sugar, put them together in a cup and stir together. There's no doubt both are solids: yeast is a firm block, you must use quite a bit of force initially to crush it and even then it should remain a rather thick paste. The sugar is crystals, nothing tricky about that. And then, within a minute or so of stirring, your cup contains only liquid - not entirely fluid like water, but not much thicker than cream. Solid+Solid -> Liquid.

What process leads to that? What happens with the baking yeast when it comes in contact with sugar, that it turns from solid to liquid, and releasing enough water to dissolve the sugar?


texts: How likely is it that a person's progeny has an inheritable disorder based on this pedigree?

texts:
Case study:

A person (let's just call him "John") had 3 aunts that died back in the 1950's in early childhood due to an unknown form of neuromuscular disorder. One died at birth, one at 2 years and one at 3 years. John's father was the only surviving descendent of John's grandparents. John and his brother do not show any symptoms. John's brother has a daughter who shows no symptoms. John has two sons, one does not show any symptoms and his other son is a 4 month old who is exhibiting signs of some sort of neuromuscular problem.

John has provided me with a pedigree that he believes is correct (note, the ones with the blue square are the ones that exhibit the symptoms):

I took a bit of genetics in university, but basically I am just trying to understand the genetics here. These are my assumptions. Please correct me if any are wrong:

Since the disorder appears to prevent developing past childhood it must be autosomal recessive because everyone who exhibits symptoms is not be able to reproduce due to their early death.
Both of John's grandparents must have been carriers.
The probability of John's dad and any aunts and uncles having the disorder is 25%, and the probability of being a carrier is 50%. The 3 aunts who died must have just lucked out.
John, his dad, and his wife must all be carriers of the disorder.

However I really feel like I'm wrong about these assumptions since the math really doesn't add up. The likelihood that so many carriers for a relatively rare disorder all coming together and the fact that 3 of the 4 offspring of the grandparents died with only a 25% chance all seems improbable.

It could be that John's son doesn't have the disorder and what he has is something completely different. What do the geneticists say?


texts: Microsatellite shifts (peak calling) GeneMapper! Thesis help!

texts:
I'm a masters student attempting to conduct a parentage analysis on a population of fish for my thesis. My advisor and post-docs haven't been very helpful, so I need some help! I have dinucleotide microsatellite markers that I've run on a set of individuals.

I'm using GeneMapper 4.0 to score the alleles of said markers but something isn't making sense. My alleles are shifted to where they are not evenly distributed in their sizes. For example, at a given locus for one individual I have one allele peak at 152 while the other allele peak is at 161 (It's an obvious heterozygote).

This "shift" doesn't make sense considering my markers are dinucleotide and should be spaced 2 bp apart, right? So either 152 is actually 151/153 or 161 is actually 162/160. How can I score these and resolve this issue while keeping consistency for my analysis later? I see this shift everywhere and I've already ruled out contamination and I'm positive these peaks are real. Any pop gen people out there that have a clue what to do?

I've been stuck on this for weeks, no amount of web searching/paper reading helped.
Thanks!


texts:
Remi.b has suggested here:

  The concept of species is poorly defined and is often misleading. The concept of lineage is much more helpful. IMO, the only usefulness of this poorly defined concept that is the "species" is to have a common vocabulary for naming lineages.

Definition of lineage from Wikipedia:

  An evolutionary lineage is a temporal series of organisms, populations, cells, or genes connected by a continuous line of descent from ancestor to descendent. Lineages are subsets of the evolutionary tree of life

If we're talking about populations, how do we know if two individuals have the same lineage?


texts: Dogs bark at familiar person in Santa costume. Why? Don't dogs trust smell over vision?

texts:
Last night 10 humans and 2 dogs spent Christmas together. At some point, one human dissappears for a few minutes and comes back wearing a full Santa outfit. Upon respawning, the dogs start barking aggressively until they are calmed down by non-Santa humans. They remained attentive of Santa until he left after a few more minutes.

Why is this? Did the dogs not recognize the human because of his fake full beard and altered body shape (pillow under coat for fattening)? The human didn't shower or put on perfume or anything. I'm stumped by this and I'd love to learn the reason for this odd behaviour.


texts: Wings serve most birds for flying, or (as in penguins) for swimming. But ostriches, which exclusively use only their legs for locomotion, still have wings. Why?


texts: Question in gel chromatography experiment

texts:
Here I am trying to do
gel chromatography to separate vitamin B12 and Bovine Serum Albumin (BSA)
in this experiment, I am using sephacryl s-100 HR gel column
my question is can I use Phosphate buffered saline with sephacryl s-100 HR gel column
also since the Bovine Serum Albumin (BSA) is colorless I need some kind of Protine detection reagent to see this protein (I need something other than Coomassie brilliant blue)


texts:
What is the purpose of the “No DNA control”?

Recently I have done a forensic DNA lab experiment and I still cannot understand the use of “No DNA control”


texts: What is this green micro-organism found living in water?

texts:
I study biology in France and experiment on water filtration with plants. I found that some chlorophyll-containing micro-organisms (about 10 micrometers in length) were raised in my basin.

I can't decide if this is a eukaryote (it looks like there are cellular compartments) or a prokaryote (it's very small!). I thought it could also be a cyanobacterium, that combines features of both prokaryotes and eukaryotes. Any ideas what this is?


texts: Why is Bcl2 a good target for cancer therapy?

texts: Bcl2 is a family of proteins that are involved in the inhibition of apoptosis in cells. My question is that what makes this anti-apoptotic protein useful in cancer therapies as opposed to focusing on pro-apoptotic proteins? Are Bcl2 proteins simply easier to work with as opposed to the pro-apoptotic proteins? Or Bcl2 proteins have some sort of other characteristic that has allowed them for be the target for cancer therapies?


texts:
I am trying to get some data on gene position in the human genome and I need some help

What I tried

I downloaded ftp://ftp.sanger.ac.uk/pub/gencode/Gencode_human/release_18/gencode.v18.annotation.gtf.gz

I am only interested in gene position, so I kept only the first columns.

awk -F "." '{print $1}' /Users/remi/Downloads/gencode.v18.annotation.gtf  >> HumanGenomePositions.txt

This operation will take a few minutes. The file contains information on exon position and transcript. I subsetted the table to get only the lines that concern genes

sed -i.bak '/gene/!d' HumanGenomePositions.txt

I am left with 57445 entries. 9872 are annotated by ENSEMBL and 47573 are annotated by HAVANA. Note that there is partial overlap between the two. According to Church et al. 2009, there are 19042 annotated genes in the human genome (reported from bionumbers). There is obviously something I am getting wrong!

Question

Can you help me to get data on gene positions in humans in a handy format (see below)?

start   end
15648   65487
129841  124984
...


texts:
I am in India where it is typically a custom to marry within one's caste. Basically the caste system originated with roots in people's professions - Each of priests, carpenters, troupers, etc had a caste of their own. My question is based on the genetic basis of marriages performed within one's caste.

I know the concept of alleles where there is a dominant allele and a recessive one, like the A and O resp. in blood groups and Rh+ and Rh- in Rhesus factors. Is there a similar genetic information based on our ancestral profession in our chromosomes? Is the son of a couple engaged in farming better suited to the same profession unless he receives a couple of recessive alleles from both parents?
Generally there is a lot of unscientific information floating around about these matters. One of the grapevines is that it is genetically better for one to marry outside their caste to create diversity(?). Is such a thing true?

If genetics or biology have any role to play in these fields, I will be happy to know and learn.


texts: methods for targetted deletion of genomic regions?

texts: I would like to know what are currently used methods for targeted deletion of genomic regions in mammalian organisms or cell lines. I have heard of Zinc-Finger nucleases as a recent genetic engineering method, but I don't know if there are other methods, more efficient or better tailored, for the deletion of specific regions.


texts: Why Japanese cherry trees blossom so early in spring?

texts: My understanding is that flowers' main benefit are the insects which attracted to the shape/taste of these and facilitate cross pollination. Yet the Japanese cherry trees start (and end) to blossom (in my observation) way before the most of insects become active. What is the evolutionary explanation for such a behavior?


texts: What type of frog or toad is this? I found him in my backyard in southern Alabama and he is clearly very small. I’m not sure what species it is, it’s mostly brown but has small spots on the top of his mouth and under his eyes and he is completely white on his belly. Anyone have any idea what this little guy is?


texts: Why do live crabs in a bucket prevent each other from escaping?

texts: It has been observed that crabs in a bucket will stop others from easily escaping. This observation has lead to the English language colloquialism crabs in a bucket. Has this phenomena been studied? What are some animal psychology explanations of this?


texts: Why are sperm cells not attacked by the female immune system?

texts: Whenever a foreign particle enters into someone's body, it is attacked by the white blood cells. I just want how it is that, when sperms enter the female body, they are not attacked by the the woman's immune system?


texts:
I feel silly even asking this question, but there's a quirk of my anatomy that I find interesting, and I can find nothing about it online.  I am looking for information on whether this quirk is documented, and whether it has any biological role.

I am a Caucasian male, and my quirk is that I have two different kinds of pubic hair.  On my genitals and immediately above, I have a dark wiry kind of hair like that which I find under my armpits and on my chest.  Above this, there is a second bundle of hair which is fairer (similar color to the hair on my head) and curlier.  The color difference between the two hair types is marked.  There is also a small amount of hair continuing up to my navel, which appears to be of the first type (same as chest, armpits, and genitals).

So my questions are:

Is this a common feature?
If not, is it documented at all?
Does it serve a biological purpose?

My reason for asking 3, in particular, is that I've heard multiple explanations for the existence of pubic hair.  One theory is that it indicates sexual maturity.  Another is that it is related to hygiene.  My anatomy seems to suggest both might be true: Hair under armpits is presumably for some practical purpose, like wicking sweat out of an otherwise dank crevice, and the hair on the genitals would appear to have the same effect.  On the contrary, colored hair like that on the head is presumably a secondary sexual characteristic, and the fact that I have a bunch of colored pubic hair above my genitals (where there is no apparent practical purpose, as with the hair below) would seem to serve the same purpose.


texts: Any good website/book to understand protein folding and enzymes?

texts:
I'm looking for a good, understandable and simple explanation about protein folding, mechanisms and function, and their relationship with enzymes.

I understand that the protein is a polypeptidic chain, I know its composition, but the part that I really can't figure out is "the folding of proteins", I mean "How a straight polypeptid chain turns into a complex folded structure?"


texts:
Wikipedia in its article on 'Glycosuria' says that the renal threshold for glucose (RTG) reabsorption in the kidney is around 160-180 mg/dL. Beyond which the glucose starts to excrete in the urine. But in diabetic people blood glucose exceeds in range of 300-400 mg/dL is prevalent. How this is possible? What prevents the the excretion of excess glucose into urine?

Does it mean more glucose is reabsorbed in the nephrons above its threshold limit? Also, as the glucose is co-transported with sodium, does it mean that glucose reabsorption is tightly coupled with sodium reabsorption? Does sodium play any role in crossing the glucose threshold limit?

Or is it possible that the excess glucose (beyond RTG) is actually excreted out of blood in the kidney but the hyperglycemia is caused by the fresh gluconeogenesis of the body?

Or is it possible that both these mechanisms (RTG is exceeded as well as fresh gluconeogenesis) cause in furthering the hyperglycemia?

Is it possible to measure this state?

Thanks in advance.


texts: How long does it take unused antibodies to clear the system?

texts: Say you have the flu and a normal immune system. Now you're all better but your antibody level is still elevated. How long does it take for those antibody levels to go back to a base value?


texts:
I'm working on a project where I need to find certain cellulolytic bacteria. I was looking at this list : http://webcache.googleusercontent.com/search?q=cache:CrtQ9T6K7m8J:www.wzw.tum.de/mbiotec/cellmo.htm+&cd=1&hl=nl&ct=clnk&gl=be

How could I selectively separate one of the bacteria types that I had in mind from that list?
So how would I have to extract the bacteria from the compost?


texts: How can evolution make such complicated beings?

texts:
So what I understand is, evolution is a mere mistake in the replication of DNA and this change is sometimes good and sometimes bad.

And the other day, in our biology class, we were told the functioning of the lungs and how the RBCs fetch the O2 from the alveoli and dump the CO2 out.

And I also know a little bit about some complicated processes in the body like, how the digestive system works, how the muscle cells switch to  anaerobic mode when we run out of O2 causing cramps, how the cells make ATPs in the mitochondrea.

And 1 more notable thing- the amount of complicatedness and all the neural networks in brain.

My question is- how can evolution(a mere mistake in copying a strand of DNA) make such a complicated machine, like our body. There are SO many organs, all working in collaboration to make the body work. And all of those organs are doing SO many things.

I know that this is a result of 3.8 billion years of evolution...but still... how can even a million "mistakes" make a body which is so well deisgned?

ALSO was the whitening of the polar bears a mistake too? Then what are the chances of such a mistake occuring in the replication of DNA? If it was evolution then why don't birds become the colour of the sky?


texts: White blood cells after dealing with an infection

texts: I just have a quick question. If there was an infection of a tissue within the body, white blood cells would leave the capillaries around the tissue and enter the tissues to help cure the infection. How would these cells leave the tissue after that? Would the white blood cells be broken down or would they manage to find their way back into the capillary that they came from?


texts:
As we all know, aspirin doesn't actually thin the blood, as it has been explained to me, it makes it "slippery". Slippery blood doesn't stick to itself hence this helps prevent internal blood clots (or allows blood to pass more easily around an existing clot). I also understand that having your blood too "slippery" can lead to the body attempting to counteract that and making it too "sticky".

Anyhow, my question regarding that is this, how does aspirin work? How does it make the blood "slippery"? (If there is a more medically correct term for "slippery" and "sticky", I'm all ears).

P.S. I paid the Mayo Clinic's website a visit before coming here, the information about aspirin's mechanism wasn't particularly helpful to me.


texts:
I was reading about Cas1 and Cas2 and came across this excerpt:

  ...Cas2 was identified as a metal-dependent endoribonuclease that cleaves ssRNA or dsDNA...

What does metal-dependent mean in this context?


texts: What are the advantages of mRNA vaccines?

texts:
When the mRNA vaccines for COVID-19 are administered, mRNA molecules are introduced into the cells of the subject. The translation of this mRNA determines the productions of antigens, which in turn stimulate the immune response.
Wouldn't it be simpler to have this translation happen in vitro, and then inject the antigen into the subject's body? What are the advantages of making the translation happen in vivo instead?


texts: Do non-enzyme catalysed reaction pathways exist?

texts:
Can their be a kind of chemical reaction pathway in a cell, that is catalyzed or regulated but NOT necessarily by enzymes? I could not find anything on Google.

I have almost no background in biology, and am only studying certain topics from a mathematical perspective.


texts:
I am a Pharmacology and Toxicology major at a large state school. I was only required to take physics I and II. (algebra based)

At first I thought that was fine, but I soon began to realize that I can't just memorize like my professor and book asks me too, but I need to go in-depth.

So my question is this, I am looking for a way to learn the "physics and chemistry behind physiology" or deeper that what we are taught?

For example, say we are taught that atherosclerosis can cause aneurysms and that aneurysms can rupture.

But what we aren't taught is that blood flow through a closed vessel is constant, so any dilatation in the mid-length will increase the cross-sectional area and decrease the fluid velocity to maintain flow.

In accordance with Bernoulli's principle, the decrease in velocity is met with an increase in pressure, which increases wall tension. Vessel integrity is already compromised from the three layer degradation. So now you start to see this great positive feedback loop whereby atherosclerosis damages the vessel wall causing it to dilate, which increases the pressure, which causes it to dilate further, which damages the vessel wall further, etc, etc, until the aneurysm finally ruptures. (I did not write this example, but it is an example of how I would like to learn it.  I would like to know how the author of that explanation came to that conclusion or what kind of book would explain in heavy detail.)

The question I am asking how can I learn the "science" behind the physiology?  I'm a type of learner that needs to know the how and why.  Will I need to take more physics classes?

** Sorry if I posted in the wrong section, I am new to stack exchange!


texts:
I know about enhancers and the mechanism that lead them to increase the gene expression of their targets but I was wondering if similarly DNA repressors exist. I know about protein repressors but I am looking for some kind of anti(or reversed)-enhancer equivalent in the genome which would act like an enhancer but reduce gene expression.

I am aware of repressed/poised enhancers which would kind of be that process, even if not really a pure repression of the target gene but rather a "non-overexpression". I also know about insulators but again this would be a different mechanism.

Some intergenic region binding protein repressors which by a folding mechanism similar to enhancers would repress a gene perhaps?


texts: DSSP gives the letter B for a "residue in isolated β-bridge (single pair β-sheet hydrogen bond formation)", according to Wikipedias page for secondary structure (and various other proper sources). Can somebody please explain what this is in some more detail please? If I google it all that comes up is pretty much the same as what wikipedia gives.


texts: white blood cells and cancer cells transport through lymphatic vessels

texts:
It is a well-known fact that both of these cells can reach the lymphatic vessels from interstitial space. How does it do so physically? Are there any mathematical models describing this process? It seems like there are endothelial cells along the lymphatic vessels that act like valves, so I would assume that these "valves" open, the cancer cells/WBCs would fit through to reach the lumen?

This question is also a reference request. I am looking for papers that describes the process of intravasation of WBCs and cancer cells into the lymphatic capillaries? Mathematical models are preferable but this is such a niche topic that probably there are no mathematical models.


texts: Could sympatric speciation occur in humans, for instance, separating blue collar workers from white collar workers?


texts: Are there special pairs present in the RC of both photosystem I and photosystem II?

texts:
I am confused regarding the existence of special pair (primarily regarding PS2). Do both, P680 and P700 have special pair?

I have checked various sources online and have come across conflicting information. For instance wikipedia article on Photosystem (https://en.m.wikipedia.org/wiki/Photosystem_II) says:

  Unlike the reaction centers of all other photosystems which have a special pair of closely spaced chlorophyll molecules, the pigment that undergoes the initial photoinduced charge separation in PSII is a chlorophyll monomer.

This is hyperlinked to a study by AW Rutherford which says:

  It is proposed that the key event in the evolution of PSII was a mutation that resulted in the separation of the two pigments that made up the special chlorophyll pair, making them into two chlorophylls that were neither special nor paired.

However, Voet and Voet 4ed says that there are two Chla molecules that are analogous to the special pair seen in Photosynthetic Bacteria Reaction Centre (PBRC).

Additionally, I found this (http://www.life.illinois.edu/crofts/ahab/psiistrc.html)

  The nature of P680 (the primary donor Chl) is still controversial. The dimeric special pair expected from bacterial centers has not been unambiguously demonstrated, although H198 of D1, and the equivalent in D2, are conserved as putative ligands, and the near IR band of P680+ is diagnostic. Several suggestions have been made that P680 might be monomeric (8-10), and more equivalent to the ancillary Chls of the bacterial reaction center.

The article is not dated unfortunately but I checked that all the citations are prior to 2000.


texts: Just moved into a new house in Puerto Rico and I found this tree in the back garden. Can anyone tell me what tree this is, and whether its fruit is edible?


texts: How does water buffer a sudden drop in temperature?

texts:
A property of water is that it is slow to heat and cool. According to my biology book, some energy from an increase in temperature would spent breaking hydrogen bonds, so that temperature does not rise too fast - helping a cell to maintain homeostasis.

As far as I can tell, this answer does not explain how a drop in temperature would be slowed down by water in a cell. How does water slow down heat loss? Is it just because it is difficult for the heat that is already inside the cell to leave?


texts: Is it true that viruses cannot be seen with phase-contrast microscopy?

texts: There appears to be a lot of material on the internet claiming that viruses can be only seen with electron microscopes, and not with light microscopes. To the contrary, for example this old paper published in Nature states that viruses can be seen using phase-contrast (light) microscopy. Who's correct? What is the smallest thing I can see using a phase-contrast microscope?


texts: Orangish-coloured insect living in wood chips

texts:
Can anyone Identify this organism?

I dug it up in a pile of 5 year old wood chips in Cleveland, Tennessee, United States. It is about 4 inches long.


texts: What determines whether a reaction using ATP produces ADP or AMP?

texts:
Most reactions using ATP seem to involve:
ATP → ADP + Pi
but in some the reaction is
ATP → AMP + PPi
followed by hydrolysis of the pyrophosphate:
PPi → 2Pi
Is there any principle that determines which ATP-requiring reactions generate ADP and which generate AMP? And is there any reason why the generation of inorganic phosphate does not proceed as follows?
ATP → ADP + Pi
ADP → AMP + Pi


texts: What was the evolutionary benefit of enclosing hemoglobin in cells?

texts: The ancestral solution to oxygen transport is with hemoglobin (or, similar proteins) dissolved in blood (or, "hemolymph", but, basically, dissolved in water. ) What was the advantage of enclosing the oxygen-transport proteins in cells?


texts: Why does caffeine give you so much energy, while being so low on calories?

texts:
There's definitely something I'm missing here.

Since calories is a unit of measurement for energy, and caffeine seemingly gives you a lot, how can the labels on caffeinated products have such a low calory count?

I would presume that caffeine doesn't really have as much energy as it seems to give you? In which case, what does it do?

Thanks in advance!


texts: I have seen nurseries selling plants that grow to trees bearing different fruits. Eg: A single plant that produces fruits of peach, plum, apricot,etc. Here is one website that advertises such trees. So in conclusion any tree could be grafted to live in a trunk of a similar kind of tree. How come animal parts cannot be transplanted with other animals of the same kind. Why is it not possible to use any animal organs for humans using transplants.


texts: In which direction does ATP synthase rotate?

texts: I heard about the rotation of ATP synthase in a biochemistry course. The professor said it will rotate counterclockwise. Is that true? If so, what mechanism defines its direction?


texts: Help id mushroom found in West Midlands, Egland

texts: I found this mushroom yesterday. It looks like an oyster but it grows in some poorly kept lawn. I am sure there was no tree there in the past. This spot was landscaped a couple of years ago after building some blocks of flats. I turned it over, hoping to find some piece of wood, but there was nothing. It has a mild mushroomy smell. Do you have any ideas what it may be?


texts: Being able to write/type different texts using each hand respectively, at the same time?

texts:
Has there been any documentation of being able to either write down (jot down) or type in (key in) different texts using the left hand and the right hand respectively, simultaneously?

So, I'm interested in whether or not it has been documented that certain individuals can do this, and I would be greatly interested in any literature on the subject. For example, have there been any pedagogics who have argued this exercise would be beneficial for the development of individuals?

Note: Of course, many people could do this, if they would do it extremely slowly; so obviously I am interested in the maximum velocity.

See also: Being able to read one text in braille using sense of touch and, at the same time, read another text visually?


texts: Can you Transfer Cancer Between People via Saliva or other Bodily Fluids?

texts:
This may sound like a strange question. But could a Cancerous cell be transferred from one person to another from Oral contact e.g. Through Saliva, or other exchange of bodily fluids?
I know that other diseases from Bacteria / Viral can be transferred in this way, but does the same apply to Cancerous cells? - or would the recipient's body just breakdown and destroy the cancerous cells?


texts: Do primates have genetic predisposition to dominance hierarchies

texts:
I’m looking for some evidence to prove (or disprove) that primates are genetically predisposed to dominance hierarchies. I would appreciate any pointers/references to scientific literature.

PS:
The reason I am interested in this is as follows: primates (unlike many other less sophisticated animals) have a very little number of instincts. And yet certain types of behavior (for instance strong dominance hierarchies) seem to be a common case for some species; baboons, for example. And yet there are known cases of baboons (Sapolsky’s example) of a radical shift in social behavior towards less agressive and less dominance-based. This nevertheless looks rather as an exception and if so, raises the question if there indeed is a genetic predisposition to a certain behavior type.


texts: What does the hornet do on the ivy blossoms?

texts: We've got blooming ivy growing around a tree. Since several weeks lots of hornets have been whirring in the foliage and I wonder whether they want to feed on insects that are lured by the blossoms or whether they come for anything they get from the ivy plant.


texts: What determines the influx of calcium ions in the voltage-gated ion channels?

texts: Calcium channels play a crucial role in neuronal signaling by helping the synaptic vesicles to fuse through the synaptic active zone and release their neurotransmitters. My question is, at a given moment, what determines the influx of calcium ions in these channels? Where are the ions coming from and what is their source? Is the influx determined by the source by changing the ion flow, or the ion flow is constant and the influx of ions into the synapse is only regulated by opening/closing of the channels?


texts: Do variant callers miss rare variants in reference?

texts:
Generally variant calling programs (such as GATK-UnifiedGenotyper) look for differences between reference genome and submitted sequence. However, we all know that reference genome consist rare variants in various positions. If submitted sequence has this rare form of that variant, variant call doesn't see it and doesn't report at all. However, that variant could be very precious for analysis.

So, how can I solve this problem? What should I do to not miss that rare variants even they are in reference genome?


texts: Is there something that makes flies slower at high altitudes?

texts:
At first glance, higher altitudes equal lower temperatures, which would likely slow down cellular metabolism.  However, while backpacking in New Mexico in ~90 degree weather, I experienced the same thing -- the flies were slow enough I was able to catch them easily in my hand, as well as with chopsticks.

Is this related to air density?  Why are these flies so much slower to react and move about in the mountains.

Also, does this question even belong here?


texts:
I am trying to understand a paper about ethanol: "Generalisation of ethanol with drug mixtures containing a positive modulator of the GABAA receptor and an NMDA antagonist" (Stolerman & Olufsen, 2000)

In the abstract it says,

  "After drug-appropriate responding with the training mixtures reached 85%, generalisation to ethanol was examined in extinction tests."

I can't find a definition for "generalisation" in Google searches. What does it mean? I don't have a background in biology, so simple answers are preferable. Thank you.


texts: Does hybridizing a specific flower affect the offspring?

texts: If among several flowers within a plant, there is a specific flower that is slightly larger or brighter or has an extra petal, will this trait be possibly passed on to the offspring? In other words, does picking a specific flower to hybridize matter and impact the offspring or does the offspring inherit the general traits of the whole plant and any flower has the same impact? Just wondering if when hybriding a plant, I need to be selective on which flower to choose.


texts: Examples of prey predator interactions where density of predator is very low and prey form groups when the predator attacks the prey for food

texts:
Examples of prey predator interactions where density of predator is very low (has a threat of extinction) and prey form groups when the predator attacks the prey for food.

I have searched this in net but not get examples. Please help me to supply some examples with a brief interaction of type discussed above.

EDIT

Specialty of predator:

Predator population has a threat of extinction due to their low population. They have the difficulties in locating acceptable mating partners for sexual reproduction during their receptive period due to low population densities.


texts: Why can only small molecules pass through the phospholipid bilayer of the cell membrane?

texts: TO put simply: I am just wondering what mechanism or substance only enables small molecules to pass through the cell membrane. Is it cholesterol? My textbooks are not very clear.


texts:
Does anyone know this type of mushroom? It grew during the last week in large numbers in one of my pots on the balcony, location Zurich, Switzerland. A smaller part of the soil is from the wood in the neighbourhood, so it might have originated from there.

I spent some time researching on the Internet, and think it might be related to the Armillaria family. An expert opinion would be very much appreciated.


texts: Can someone give me a good explanation of what is neuronal computation and some examples of its use in neuroscience investigation?


texts: Methylation Data for Erythrocytes (Red Blood Cells)?

texts:
Why is it that white blood cells (leukocytes) are highly characterized in DNA methylation pure cell line profiling, but I can't find any profiles of red blood cells (erythrocytes)? Is blood considered a pure tissue type?

I'm following the deconvolution of DNA methylation data by cell type (white and red), but I can't do this without pure cell line methylation data. Can anyone help me understand either:

Why red blood cell DNA methylation data has not been purified and collected yet.

OR if it has...

Where can I access the methylation data for red blood cells (erythrocytes)?

Thanks so much for any help!!!


texts: Which organs need to have fluid compartments in order to develop properly?

texts:
I am a student, slightly struggling with the new concept of fluid compartments. I know that there are two main types of fluid compartment, extra and intracellular fluid. I also read that most organs need to have these fluid compartments (established by cell-cell adhesions within tissues) in order to function and develop properly.
My question is what type of organs require these fluid compartments? Would it be the kidneys and the intestines for example?
thanks


texts: Why don't plants get hot under sunlight?

texts: I've read that efficiency of photosynthesis is only like 5%, and it operates on visible light spectrum, not infrared (which is heat radiation). Which means light should either be absorbed and increase plant temperature, or reflected, and heat what's around the plant. But when you get near or touch plants under sunlight, they are at ambient temperature. In contrast, if you touch a metal plate, ceramic tile, rubber, plastic, asphalt, concrete, sand etc, that's exposed to strong sunlight, they are very hot, either because they reflect heat onto you (sand), or because they absorb heat and their temperature is high (asphalt). But with plants, it seems like neither happens, and it stays cool. How does that work?


texts: Why does cell waste energy in meiosis, between meiosis 1&2

texts:
As far as I have learnt about meiosis I have read that anaphase 1 is followed by telophase 2 where chromosomes change back to reticulum.but in the very next stage i.e prophase 2 they again start condensing to form chromosomes again.i have also heard that is most species, cytokinesis is simultaneous and not successive( which means that the 4 cells undergo cytokinesis together)..

If this is the case, then what is the need for a cell to waste its energy on making chromosomes back to reticulum at the end of meiosis 1, and again condense it in the very next step
Can't it directly continue on to prophase 2!

It sounds ridiculous,...but I beleive there must be a reason behind it, because the last thing a cell would want to do is to waste its energy in such things.

Thanks in advance


texts: Trying to find the right plasmid expression vector for e. coli c600

texts:
I am very new to the concept of gene cloning and transformation. I am trying transfer the arenite oxidase gene cluster (9kb in length) to E. coli strain C600. I want the E. coli strain to express this gene in order to oxidize arenite for bioremediation of groundwater. I am just realizing how complicated it really is to select the right expression vector. I have not studies this topic at all at school (still in high school); I am just studying this topic on my own. I am worried that my 9kb sequence could be too big for the plasmid vector or the bacterium. I have been trying to find the right plasmid expression vector for days, and it seems like everyone I find isn't quite right.

I have been kind of vague, so here is the whole story: I am in possession of a gram-negative bacteria that can oxidize arsenite into arsenite very efficiently. The gene cluster that is responsible for this is Aro, which is 9 kilobases in length, and I am looking to use a heat shock method to transfer that gene cluster into a specific bacterium (I found that E. coli C600 might be a worthwhile candidate). I have everything I need for the extraction of the DNA and PCR, but I am just trying to find a plasmid expression vector that I can insert into E. coli C600. Originally, I looked at pUC19, but then I found out it is only a cloning vector and not an expression vector. Then I looked at the pET system, but there are so many selections; I cannot seem to find the right one.

Are there any suggestions for what vector I should use or any guidance on how to find one?


texts:
We spotted this thing crawling around a (thankfully empty) bowl in our apartment in Barcelona, Spain. I have never seen anything like it. It appears to be some kind of caterpillar-like insect, but it is inside a flat, leaf-like shell. It can only move by sticking its head out a hole in the tip of the shell and it has to pull itself by its front legs (no legs under the shell). But it can actually pop out of either end of the shell! When it's threatened, it just hides inside the shell completely.

I'm completely flummoxed as to what this thing is. Does anyone have any clue?

(click the images for full-size)


texts: How are the images of both eyes combined to form one image?

texts:
When you see an object by one eye, ex.right eye, you see it from the right direction and the opposite if you see it by your left eye, but when you open both eyes, the image appears somehow centric in between.

  How does the brain combine both images to form the final image?


texts: Do all plant hormones of one group show the same qualitative effect with respect to their target pathway(s) and the biological response?

texts:
I wonder, terms like "Auxin", "Cytokinin", "Gibberellin" etc means NOT a single compound; but a class of compound.

For example "Auxin" does-not mean a single compound, but several compounds such as : natural auxin (IAA in all plants*, 4-Cl-IAA in pea*, IBA in mustards*) and their synthetic analogs like NAA, 2,4-D, 2,4,5-T, dicamba ( * ), etc.

Similarly there are more-than one natural compounds under the group "Gibberellin" (such as GA1, GA3, GA4, GA7 etc),

and similarly more-than one compounds under cytokinins: natural: cis-Zeatin, 9RiP ( * ) etc. and their artificial analogs such as kinetin ( * ), 6-BAP , etc

Now, my question is, would all the auxins work in exactly the same way? or would there be slightest difference (qualitatively) between their actions? and similarly, Would all the cytokinins work the same way? and would all the gibberellins work in the same way?

(So far I heard that they have difference in their 'strength' i.e. in which concentrations they are undetectable/optimal/toxic to a cell. (i.e. quantitative difference), but don't have any references for this.)

But beside that;  my question is, would there be ay qualitative difference?

So far I haven't found anything clear-cut about this in any book or on the web.

Any help welcome

  (  *  )  (ref.  Plant Physiology/ Taiz and Zeiger, ed3; chapter 19, fig. 19.3, fig. 19.4)

Update:

In one source, Plant Tissue Culture: Theory and Practice/ Bhojwani and Razdan, (edition= ? ) 3.2.3. Growth hormones; , it is told that "IBA and IAA are widely used for rooting, and with a interaction with a cytokinin, for shoot proliferation.  2,4-D and 2,4,5-T are very effective for the induction and growth  2,4-D and 2,4,5-T are very effective for the induction and growth of callus. 2,4-D is also an important factor for the induction of somatic embryogenesis."

However there I could not found,  is this difference is really due to a difference in biological (signaling-path) process, or due to some-other superficial difference (solubility, binding with same receptors, etc) of these applied molecules.


texts: What decides the position of the node of Ranvier?

texts: The oligodendrocytes makes the myelin sheath in CNS and schwann cells make it in PNS. What decides where the oligodendrocyte or Schwann cell will attach and start forming myelin sheath? Is it genetically determined? Is it random? Is there any disease associated with improper positioning of node of Ranvier?


texts: Strange Exoskeleton Found in Maine: What is It?

texts: There is a gall like object or exoskeleton attached to a plant stem I have found. At first I thought it was a cicada but it is not. The object cannot be identified by me. Attached are some pictures of it. Could you identify it?


texts: Can genetically modified genes jump to bacteria in the eater's intestine?

texts: The Guardian ran an article a while back talking about GM gene's jumping to bacteria in an eater's intestine. Has other research confirmed this phenomenon?


texts: What is the name of this flower with purple leaves and orange inner part in NYC?

texts:
I've photographed this flower a few days ago in New York City:

Does anybody know the name of it? (and how is the orange part called?)


texts: Will a garter snake eat unusual prey if made to smell like something normal?

texts: I have noticed that my garter snake only eats after it has smelled it's prey to make sure it is a slug, and it doesn't matter whether it's moving or not. If I were to coat, say, a caterpillar with slug slime, would my snake try eating it?


texts: Appropriate model to test if environmental variable is significant between two species?

texts: I want to know if a given environmental variable has an effect on the range of two species/two groups of species. Specifically, I am interested in testing if one species has a "preference" for higher/lower ranges over the other (for example, do blue frogs prefer colder temperatures than red frogs?). I have occurrence data for my species as well as environmental data in a grid over the area. Can anyone point me in the right direction?


texts: HIV spreads only through body fluids. If a mosquito bites an HIV infected individual and then an uninfected individual, will the virus spread  to the new individual?


texts: What is the difference between a dermatome and a sensory neurone?

texts:
I read that a dermatome is an area of skin supplied by a single spinal nerve but that this is sensory information? Why do spinal nerves supply the skin? I thought it was the other way round- sensory information is carried by a sensory neurone to the spinal cord.
Please could someone explain this in simple English because I am really confused.


texts: How many electrons does the b6-f complex need to pump one proton into the thylakoid lumen?

texts:
In photosynthesis, photons are used through photolysis to split water molecules and retrieve their hydrogen ions and electrons in the water-splitting complex. For each four photons, two water molecules are split and four electrons are retrieved.

The electrons will go on to pass into chlorophyll a in photosystem II and after being excited by another photon, pass through a series of electron carriers and drop energy along the way. One of these electron carriers is the cytochrome b6-f complex which uses some of this energy to help pump hydrogen ions from the chloroplasts stroma and into the thylakoids lumen.

However, I'm unsure of exactly how many electrons the b6-f complex needs to pump each hydrogen ion across the membrane. Is it 2? 4? I've been unable to find an answer anywhere so far.


texts:
In order to generate a tube system of low resistance, sieve elements lose most of their cellular components such as the nucleus, cytoskeleton, ribosomes, tonoplast etc.
Mature sieve elements contain structural phloem specific proteins (P-proteins), mitochondria, ER, and sieve elements plastids.
In plants, sieve tube cells lose their nuclei at maturity (just like our RBCs), and thus lose their chromosomal DNA, but they don't lose their mitochondria.
In eukaryotic cells Wikipedia has divided extrachromosomal DNA into three parts based on where it is seen (I guess):

Mitochondrial
Chloroplast
Circular

Sieve tube cells have mitochondrial extrachromosomal DNA at maturity, but I'm not sure about the existence of extrachromosomal circular DNA in these circumstances.
Do sieve tube cells have any extrachromosomal circular DNA at maturity?


texts: How does entry of Ca²⁺ to the myocardiocyte make it more contractible?

texts: I'm trying to understand why an increase of Ca2+ entering into the cell, increases the force of the heart contractions. Based on what I have watched in many lectures videos on Youtube (this one- "interactive biology" for example on 4:45), Ca2+ basically slows the repolarization in phase II of the action-potential membrane, and I don't understand how it does the cardiac cells more contractible. Or maybe the answer is pinned in the words "typical cardiomyocytes" and then I didn't get it.


texts: How it is determined that a particular gene or set of genes is responsible for a trait? Is it just a statistical analysis of people showing and not showing the trait and the genes they have (or don't have) and their variants (alleles)? Or, there is something more.


texts:
This is a quote from Dey et al 2014:

  Hatching asynchrony is thought to be adaptive because...

What exactly does adaptive mean here? Does it mean hatching asynchrony has fitness benefits? Or does it mean hatching asynchrony is likely to be selected for?


texts: I found this creature on the beach in San Diego. It is 8cm long and the end to the right is the mouth. The underside is exactly the same as what is visible. What is the name of this species.


texts: Can human organs be transplanted indefinitely?

texts: I watched this movie, where they rented hearts to people for a year. I wonder if it is possible to transplant a heart indefinitely from person to person, or does the heart have a lifetime? So, do human organs age and eventually die, or is it possible to transplant organs indefinitely? What is the limiting factor for life of human organs?


texts:
Are there any microscopy modalities or techniques for in vivo imaging at higher resolutions than the diffraction limit?

I was looking at this list: Super resolution microscopy, but they don't talk about in vivo imaging.


texts: What is the distance between the 3' 18s rRNA (the Kozak consensus sequence) and the A-site of eukaryotic ribosomes during protein translation?

texts:
Reposted from Quora

The Kozak sequence is shown to be important in translation initiation, and the A-site is the anti-codon recognition site. If the distance is not known, how could I find out what it is? Is the crystal structure of the whole mRNA-rRNA-tRNA complex determined? If so, what modeling program would be best for establishing intermolecular distances?


texts: What non-SDS buffer can I use to isolate protein from mammalian cells? The protein is intended for testing electron transport chain complexes.


texts: What are some (bioinformatic) methods to characterize potentially novel gene transcripts?

texts: I am working with a few novel transcripts of genes- before I confirm their existence experimentally, I would like to perform some bioinformatic analysis. I have already considered coding potential, protein domain prediction, transcription factor binding sites, sequence homology, and RNA secondary structure (still a little unsure how to use this one). These transcripts were discovered using RNA-Seq. Are there any other elements of genes/confirmed transcripts that I should look for in the sequence of my transcripts and corresponding softwares? (I can find the software myself if necessary, but I have run out of characteristics to search for). I would like to characterize these transcripts structurally and functionally as completely as possible, including potential protein function, mRNA degradation, etc - some new features for what to look into would be appreciated.


texts: Why does spiral or annular thickening occur in water conducting plant vessels?

texts: From what I behold, spiral and annular thickening of xylem and trachied cell walls leaves a lot of not thickened regions of cell wall. Lignin is the material which prevents water from escaping these water conduits. If lignin is absent from certain regions, does not that mean that water flows out of the xylem vessels and trachieds through their cell walls? If so, is not this disadvantageous to a plant? Why can't a plant simply thicken the cell walls with uniform lignin deposition, only sparing pits to allow lateral flow into the required tissue? I would appreciate your kind response.


texts: What causes the bright flash of light when poking my eye?

texts: Recently, I poked myself in between my eye and eye socket, right below my eyebrow, and sometimes I would get this flash of light. Others have tried this too, and they also had a flash of light. I am wondering why is this the case. Does it have to do with the nerves in the eye?


texts: What's the Evolutionary Purpose of Religion?

texts: I would imagine the answer to this question would be that religion tends to cause greater compliance of individuals within society, so it is pro-society. Plus these religions tend to incorporate some knowledge obtained by trial and error, an example of this is the fact that in Judaism the consumption of swine is forbidden which would be an evolutionary advantage seeing how swine is notorious for its parasitic constituents. Additionally religion offers an explanation for some of the phenomena that were once and still are poorly understood. Such things include near-death experiences. It also adds to motivation and tends to confer some other advantages such as a decreased rate of suicide due to the condemnation of suicide by the majority of religions.


texts: Why are restriction sites palindromic in nature?

texts:
Any restriction site given in any fragment of DNA or vector molecule is a palindrome. eg restriction site for the endonuclease EcoRI is

5'...GAATTC...3'
3'...CTTAAG...5'

Clearly, this is a palindromic sequence. Why is that?


texts: What causes a selective shift of colour perception after removing wavelength filtered glasses?

texts:
Background

To improve sleep by reducing blue-light melatonin disruption, I wear night-glasses that filter short wavelengths (e.g. something like these). With these glasses on, both the top and bottom bars of this test image will appear visually identical:

(Source: Personally derived from this public domain image and released to public domain)

But the colour spectrum you "see" while filtering the blue light will not appear to be either of these bars; instead some partially de-saturated hybrid of the two. I think this is probably due to a pervasive blue wavelength of the LCD back-light regardless of defined colour contrast.

However, there is something else odd going on. If I wear these glasses for several hours and then remove them for some reason - all the blue colours I should see will be muted, partially de-saturated or even interpreted as a shade of green for at least several minutes afterwards (I haven't stop-watched the effect). Freaky.

Question

Why is this selective shift of colour perception occurring for a while after removing wavelength filtered glasses?


texts: Does avocado and orange have a common ancestor?

texts: While I'm eating my orange, I felt as if I was eating avocado. It might be genetic manipulations perhaps but it made me think if they have a common evolutionary ancestor. Is there?


texts: What is the most recent well-attested common ancestor of chimpanzees and humans?

texts:
Humans and chimpanzees are related and thus have a most recent common ancestor. Of course pinning down this precise point is essentially impossible, so I'm interested in close ancestors of this most recent common ancestor. Also, I'd like to know things about it -- how it compares to common chimpanzees, bonobos, and humans in various ways -- so species known only from fragmentary evidence are less interesting to me. Ideally I'd ask for something with at least one near-complete skeleton and a separate (perhaps less complete) find, but as a non-expert I'd be happy to settle for whatever is considered to be well-attested.

So, what is the most recent well-attested common ancestor of chimpanzees and humans?


texts: Will amylase inhibitors affect the colorigenic reaction between starch and iodine?

texts:
I'm doing an experiment for my IB bio EE involving colorimetry. I'm not experienced at all with colorimetry, so I'm having some trouble planning it. The experiment is on enzyme kinetics, and I'm testing the effect of an inhibitor on the rate of digestion of starch by alpha-amylase. Currently, my plan is just to use a starch solution with an iodine indicator, add the amylase and inhibitor and measure the change in absorbance of a certain wavelength over time with the colorimeter, however, I'm worried that when I add the amylase and the inhibitor it'll affect the colour of the solution quite a lot. Will this be an issue, and if so is there a better method I could use to control for it?

Any help would be appreciated, this is my first time actually planning an experiment and I'm finding it difficult :)


texts:
I fail to see how natural selection can build any kind of new functionality.

New functionality in a design requires sacrificing a complex series of meanwhile useless steps before the new functionality works and becomes advantageous.

For example, if I want to upgrade a stationary chair to a wheelchair, there are many intermediate steps that must be done (which are not advantageous) before the added functionality becomes advantageous.

If a human being sits there and tries to intelligently assemble the wheelchair in such a way that it will be advantageous at each step, he will not be able to do it. it just doesn't work like this.

Can someone fill me in as to how this works and whether there have been experiments that demonstrate this, for example, having someone assemble a simple functional design with the limitation that every few step adds advantageous functionality.


texts: Rate of Evolution of population of long lived individuals

texts: Is it necessary that rate of evolution of longer lived trees will be lesser than that of annuals ? I understand that new individuals will come up faster in annuals  and it may adapt to varying conditions faster but does it necessarily imply that long lived trees will evolve slower ?


texts: If human eyes watch an area, what's the shape of its capturing shape? Rectangular? Half spherical?

texts: A normal camera can capture a rectangular image. If human eyes watch an area, what's the shape of the captured region? Rectangular? Half-spherical?


texts: I've recently become aware about existence of such phenomena. From my naive point of view, I understood it as existence of two general types of neural cells, one type serve inhibitory purpose and the other one provide excitation, all of this happens through variation of concentration of different mediators in synaptic connections, right? So in this process (transmarginal inhibition), in a nutshell, provoked by overwhelming stimuli, layer of cells which inhibit inhibitory cell start to show increase of activity and hence inhibitory cells can no longer control activity of currently "excited" cells which result in "paradoxal", reversed behavior. Sorry for this clumsy explanation of how I understood this, please correct my view. If i can abstractly think about evolution of some particular part of biological system as a function which tries to arrive at "local maximum", what type of arrangement of environmental variables could introduce this kind of structure which suffer from such horrible drawback. I mean, there was some input and desired output (adaptation), in result we got construction which could be shut down be intensive external influence and permanently corrupted.


texts: Why is prothrombin time test not used for heparin

texts: Prothrombin time test is used for the monitoring of warfarin but not heparin. Why is this used for warfarin monitoring and why is it not used for heparin monitoring?


texts: In genome research, what is the problem in Mapping that may be caused by reads being too short?

texts:
In the following scenario: You were given short sequence reads of plant RNA obtained from a next-generation sequencing machine (fragments of 20–30 nucleotides in length). You attempt to map them back to the genome, but a significant proportion of them do not align.

The question is: give some obvious explanations why the alignment of short sequences can fail, apart from possible contamination or technical difficulties during the preparation of the RNA.

I would answer it as because reads are short, and because of introns(since it is RNA)

Another scenario: There are some indications that the problematic sequences come from an uncharacterised plant RNA virus. What would you do next? What are the specific caveats with short sequence reads?

I got the above questions, I am a computer science student doing bioinformatics, any biologist could answer it will be well appreciated


texts: Is it possible that nearly human mammals existed before the last mass extinction dinosaurs?

texts:
From time to time I am hearing people discussing about the possibility that men and dinosaurs meeting some time ago.

The oldest mammal remains seem to be about 35 million years old, quite some time after dinosaurs have perished.

Also, it is very implausible for a primitive man to manage to survive near the dinosaurs (I think they would be very hard to handle even using current technology).

Question: is it even remotely possible for advanced mammals (nearly humans) to have coexisted with dinosaurs?


texts: What evolutionary process lead to so much variation in MHC? What is the advantage of having such variation?


texts:
I searched the internet on the question whether darkling beetles can fly, and I read mixed results to it. Some say they can, there are even videos about it, but then again they say that they cannot, due to fused wings or the like.

I am currently interested in mealworms, and plan to farm some myself, and some people show their containers without covers, even though the beetles should be able to fly out then, shouldnt they?

This is really confusing to me, thanks for the awnsers.


texts: How long ago did the mutation arise that gives rise to sickle-cell disease?

texts: Is it known how long ago the mutation arose in Africa that gives rise to sickle-cell disease and protects from Malaria in heterozygote carriers?


texts:
Sexy son hypothesis.

It states that females are attracted to certain traits in males, because these traits will be attractive in her sons either. But isn't this circular?

Like "I'm attracted to that male because he is the son of an [formerly] attractive male". And you can repeat the process infinitely, going through granddad, great-granddad and so on. Doesn't this hypothesis presuppose some sexy traits that are sexy with no cause?


texts: What are some possible causes that might explain why the global temperature has remained relatively constant in the last decade?

texts:
First - I do not know if this is the best site to pose this question.  However, stack exchange does not appear to have an ecology sub-site. That said, this appears to be the most appropriate place post this question.

Consider this chart:

The chart was retrieved from here here.

I am curious as to whether anyone has any thoughts regarding this trend - note, however, that this is one chart among several that I came across on reputable site. All seem to depict this observed "capping" effect between roughly 2000 and 2010+. Unfortunately, I don't have much to offer right now since I am still looking into it.

Any input is appreciated.


texts: Is the affinity of an enzyme or transporter for its substrate or solute influenced by the amino acids at the binding site?

texts: The affinity of an enzyme or a protein transporter indicates the strenght of the binding of substrate/solute. An enzyme with higher affinity binds its substrate more strongly than a counterpart with a lower affinity. Is affinity always a function of the protein structure of enzyme? If the same enzyme in two different species had different affinities for substrate, would that indicate that there were differences in amino acids at the binding sites of the enzyme in the two species?


texts: Why are some bird species placed as family Incertae sedis while some families are simply monotypic?

texts:
The Bananaquit and Western Spindalis are passerines of Incerta sedis. But species such as the Osprey, Limpkin and Olive Warbler belong to their own, monotypic, family.

Why aren't Bananaquit and Western Spindalis simply assigned to a new family?


texts:
Armadillos evolved in South America. When the continent was joined with North America, one species - the nine-banded armadillo - spread north into Middle America.

Apparently, the armadillo reached Texas about a century ago. Does anyone know why the armadillo's range continued to move northward? Maybe it's just part of a natural process following the retreat of the Ice Age glaciers, but I wondered if human impact on the environment might have something to do with it.


texts: Black/dark-red smooth West African worm, full of red blood

texts:
This chap was strolling across my bathtub in Freetown, Sierra Leone, one day after very heavy rains and flash flooding. From its course, it appeared to have come up the bath plug from the drains.

It's about 2mm-3mm wide at the fattest points and 1mm wide at the thinnest points (which vary as it moves). It's maybe around 10cm in length. The picture's not the clearest but (to the naked eye) it looked almost completely featureless - smooth (no visible rings), and no obvious hooks or features at either end.

It was moving to the right from the point of view of the photo, and moved by narrowing and elongating unmarked segments about 2-4cm long each rather than the whole body. I say segments, since it seemed to be the same sections each time, but when it wasn't moving there was nothing to distinguish these segments. Its movements began by elongating the very front 2-3cm, then it'd feel around, come down, and other (unmarked) segments in the body would expand and contract to bring the rest of the body after it.

While I'm pretty sure it's not either of the two most notoriously nasty West African parasitic worms (Loa Loa or Guinea Worm), I didn't want to to take any chances, and we had nothing to isolate or store it in, so we carefully squashed this one after taking photos then cleaned the plug hole with boiling water and cleaner.

On squashing it, it burst in a very similar way to a recently-fed mosquito or bed bug with a splatter of what looked exactly like regular human/mammal blood. I've not seen this before from a worm. Each 5mm or so of worm body contained about as much blood as a well-fed mosquito.

I've done a little browsing of species of bloodworm but didn't find any obvious matches.

This might be unrelated, but the bathroom in which this worm surfaced has for several weeks had a small but constantly replenishing population of tiny flies like this, which I never questioned because they look almost exactly like regular drain flies. There's usually 1-3 of these flies on any given day, even after wiping out all of yesterday's flies, and I've not seen them anywhere else in the country. In this image it's about 3mm from wingtip to wingtip - much smaller than the worm.


texts: Confusion about Lotka_Volterra model for two competing species


texts: How efficiently does the human body convert the energy stored in fat into kinetic energy?

texts: I read that one gram fat contains 9 kcal energy. There are many tables around claiming that x type of exercise for t duration burns roughly E kcal energy. I'd like to estimate how much weight one will lose by following a certain training plan based on these two values. I don't know whether I need to calculate with the heat loss too, or not. Most of these tables don't tell anything about the method they used to estimate the E values. I could workaround this problem by ignoring efficiency, but I can do that only if it is relative close to 100%. As far as I know fat goes through beta-oxidation and the citric acid cycle. After that ATP is used to move the muscles. It is hard to find anything about how efficient this process is.


texts: Which will produce more oxygen? A few large trees or a greater number of smaller plants?

texts:
In a given area A, we have two choices -
(i) we can plant maximum number of trees (which are larger in size) possible in A, say m
OR
(ii) we can plant maximum number of plants (which are smaller in size) possible in A, say n
(evidently m will be smaller than n)
Which choice will yield more amount of oxygen?
It can be assumed that the total number of leaves capable of Photosynthesis is N and is same for both the cases.


texts: Classifying Polypeptides (and/or Proteins)

texts:
Since polypeptides are a linear chain of twenty amino acids, each having a single letter abbreviation (e.g. Alanine = A). So can a polypeptide be represented as just the sequence (say: ADN for an Alanine, Aspartic acid, Asparagine polypeptide)?

This method of classifying polypeptides would lead to a possible 8000 (20**3) variations just for 3-amino-acid-polypetides (3200000 for 5-amino-acid-polypeptides, etc.) and that there would be many variations; and for longer polypeptides - that is, proteins - there would be even more variations.

Or are only the important polypeptides and proteins named, since not every variation of polypeptides and proteins are found in the body? I would've thought that many proteins (and enzymes, etc.) are incredibly specific and so they could be classified in some methodological way, as opposed to just 'lipase' or 'carbohydrase' which provides no structural information (though it would have a long methodological name).


texts: A free book/resource for learning genetics?

texts:
I took an undergrad class in genetics. I felt it was not too intensive and I do not feel prepared for grad school (if I can manage to get in.)

Does anyone know of a preferably free resource for learning genetics?

I know the field is very large, but I would like to be competent in the field, considering I also want to learn more about genomics as well. And I figure one must first have a fundamental understanding of either computer science or biology to be successful in genomics, both of which I lack.


texts:
G'day!
I'm based in Victoria, Australia.
I'm hoping to culture springtails for my terrariums, so I went out and tried to collect some. I found them underneath a rock, which was sitting on damp ground. They certainly look like springtails, and gee they're tiny! 1-2mm. But they don't jump at all.
My first question is -- is this little fella a springtail?

Fast forward a few weeks, and these little critters still seem to be alive in a jar. However, what I believe are isopods appear to have joined them. They're super tiny though, < 2mm. And they're always hovering around what appears to be eggs.
Here's two pictures:

I read online about the lifecycle of isopods. They don't lay eggs; rather, the mother keeps them in a pouch on her underside. I also read that, absent better food sources, they can feed on the eggs of other insects.
So what I suspect is, that these are springtail eggs, and the isopods are eating them. Is that a correct assessment? And are these indeed isopods?
Thank you in advance for your help!
TLDR

Is the first picture of a springtail?
Are the second/third pictures of isopods eating springtail eggs?


texts: Increase rate of change in coding regions?

texts: If a sequence is under selection will it acquire  more changes over time because of faster fixation than if changes were neutral? Is this true or am I missing something?


texts: What's the best way to measure biodiversity?

texts:
As I understand it there are various ways biodiversity is measured, with varying results. From what I have been told on these boards, part of the difficulty is because it's hard to define a species exactly, so it's hard to count them.
What I really want to know is whether genetically engineered organisms count towards increased biodiversity but my last attempt at asking that question foundered on the rocks of species definition.


texts:
I have a question regarding the description of a subset of peptide hormones, called cyclic hormones. Two examples of cyclic hormones would be somatostatin and melanin-concentrating hormones. I know the definition is not applied based on observations of oscillations in biologic levels of the hormones, rather, it is applied to the structure. These hormones possess a single disulfide loop, giving them a cyclic (circular) topology.

My question relates to the chemical definition of cyclic in this context. Does the word cyclic imply any chemistry that forms a single loop topology, arising from any kind of chemical bond (e.g., C-C bonds in carbon rings, or S-S bonds in these hormones). Or, does the word cycling only apply to S-S bonds in the context of these hormones?  I have not seen it defined in the literature, and my inclination is that it is more a definition of topology than any specific chemistry.


texts: What is the relationship between snails/slugs and clams/mussels?

texts: Slugs and clams are both phyla in mollusca, but how can I tell which features they inherited from an ancestor? Basically, I'm curious about how excatly these organisms are related but can't find any information and do not know where to look.


texts: What would happen if most the fat in your body was rapidly converted into energy in 2 minutes?

texts:
It all started out as an argument I had with my friend.He said that "it would be the equivalent of catching a fire and burning"

But all I thought would happen is that you would now be very hyper because you have a lot of energy in you body.

Please scientific answers only.

I also happen to be in the 11th grade and I dont do bio, but I knew this would be the best place to post the question.Please dont use scientific concepts I would not understand.

You guys are probably going to ask me to give an example of a way through which it might happen. So here is one way I have come up with:
Lets say the AMPK protein malfunctions and causes all the cells to release all this energy.


texts: Which is the most extreme thermophilic bacteria known?

texts:
Extreme thermophilic bacteria thrive at any temperature above 40/50°C. Thermotoga Maritima seems to be the bacteria that can survive at the highest temperature up to 90°C (reference 1, table 2). I wonder if there is a more exhaustive list of extreme thermophilic bacteria and if there is a known bacteria that can survive at higher temperatures than Thermotoga Maritima.
References:
Ref.1 Front. Microbiol., 05 November 2015 | https://doi.org/10.3389/fmicb.2015.01209
Extremely thermophilic microorganisms as metabolic engineering platforms for production of fuels and industrial chemicals


texts: Why does resting potential not become continually more negative?

texts:
(Firstly, I know this is similar to other questions, but I have read those answers and they do not really cover this topic).

My understanding of resting potential: action potential is not being transmitted; by way of action potentials via Na+ and K+ pumps, for every 2K+ pumped in, 3Na+ is pumped out of the cell. This process is termed "resting potential" and the transmembrane pd roughly = -65mV.

If more Na+ are pumped out than K+ in, why does the resting potential difference remain at -65, why does it not continue to decrease (until an action potential is triggered)?


texts: Do mitochondria contain the genes to specify themselves?

texts:
My book says :
"Mitochondria contain their own genetic material so when a cell divides, the mitochondria replicate themselves under the control of the nucleus."
The book means that the mitochondria contain the genes which produce the mitochondria right  ?


texts: In the event of an abrasion, do mast cells cause vasodilation or vascular constriction?

texts:
Or both? I am unsure as to what mast cells will do in the event of a wound either on the epidermis or the epithelial. I know they secrete factors that mediate vascular constriction / dilation, but I can't find information anywhere as to what they do in the area where the wound is located.

Based off my current understanding, this is what I think happens:
Wound. Mast cells release mediators that cause constriction around the area of the wound, but dilation further upstream to increase the delivery of essential leukocytes (white blood cells), plasma and red blood cells.
Any help is greatly appreciated!


texts: Measuring gene similarity in two bacteria models

texts:
I'm currently working with some computational models of bacteria. The bacterium I am considering is an Ecoli K-12 which has 139 genes. I have several models of the same bacterium with different combinations of genes that are active. e.g. M1 - M3 are the models and G1 - G4 are the genes. 1 indicates the gene is active and 0 inactive.

M   G1 G2 G3 G4
M1  1  1   1  1
M2  1  0   1  0
M3  0  0   1  1

My assumption is that bacteria have a fixed number of chromosomes and randomly genes get activated. I intend to compute a similarity score between each pair of models (how similar two models are). I want to know what similarity means in terms of biology. Is a gene being active (1) considered a similarity or begin active and inactive (1 and 0)? For example if I compare M2 and M3 which similarity would be correct?

1 similarity (only G3 is active)
2 similarities (G3 is active and G2 is inactive)


texts: For a luekemia patient - how does the chemotherapy fixes the bone marrow to not produce immature cells

texts:
For ALL patient this link says 90% of the children are cured.   It has high survival rate. From what I understand is that - luekemia is type of cancer where the immature cells does not turn into mature cells. How does the chemotherapy with other drugs - fixes the bone marrow immature cells defect?

What are the survival rates for acute lymphoblastic leukemia?
About 98 percent of children with ALL go into remission within weeks after starting treatment.
About 90 percent of those children can be cured. Patients are considered cured after 10 years in remission.


texts: What does C. Elegans sense when touched?

texts: I'm reading up on C. Elegans' touch responses.  Once touched, what is it that the neurons are sensing, specifically?  Presumably, touch deforms the body cells, and that deformation is sensed by the sensory neurons. Is that correct?  Alternately, are the neurons themselves directly stimulated due to the organism's small size? (Or am I way off?)


texts:
I am trying to build a machine learning training set for bacterial protein sequences that form biofilm, and that cannot. I collected the positive sequences from the GO ontology website but for negative sequences I am not sure which sequences to incorporate into my training set.

Can anyone point me to resources for proteins sequences that are known to be not capable of forming biofilms?


texts:
Since it has six legs, I believe it's some sort of insect, but I could be wrong.

I spotted it in my Central Texas backyard (Austin area). It was very slow and not at all skittish.

For size reference, it's standing on a 2x4. It was a good 3-5 inches long, not counting antennae.


texts: How does the cell cycle affect stem cell fate?

texts: I keep reading about the stages of the cell cycle affecting stem cell fate, however I do not understand how. After all, any cell will have to pass through the whole of the cell cycle, and go through every state.


texts: How allele is related to trait that is more complex than two cases (ex. height)?

texts:
Recently I started to learn about evolution and genetics. Simple stuff at the beginning - some videos, some reading. So far, everything seems to be pretty simple and straightforward. I easily grasp the concept of gene, allele and trait as the basic level. What bothers me is, that all of examples shows allele that has two options, sometimes three - peas yellow or green, blood type IA, IB and i - so on and so on.

But traits usually aren't digital in nature, they are analog. They are gradients. You have no people that are 160cm tall or 180cm tall only - you can have one that is 160 tall and another who's 160.1 and another who's 159.95. Height seems to me as a real number which may provide unlimited results.

Is the Mendelian reasoning about alleles and traits still valid in case of height trait? How does it work in such case?


texts: What is (are) the medium of conduction for an electrical current with an external source in the human body?

texts: I am trying to get some background for some personal research I am doing into the effects of Electro Convulsive Therapy. I don't understand how electric current from an external household source, say, flows through the body. There are no naturally occurring chains of metal atoms in the body, so it can't be electron flow, but my understanding is that the electric field around an electrode is very thin, so I can't see ion flow as accounting for electrical effects in the body at some distance from the electode - particularly with AC, as I would only expect a local oscillation. I am familiar with membrane depolarisation but that is essentially a cellular mechanism - is it (or saltatory conduction) activated by an external current? I know that the body as a whole (and cell membranes in particular) function as a dielectric, but I can't see how this fits into the global picture of current flow between two electrodes. Can anyone help or recommend me a paper?


texts: Can pheromones be received other than by odor?

texts:
I'm trying to understand how deodorants affect pheromones in humans.

Wiki states:

Axilla

  In humans, the formation of body odor happens mostly in the axillary
  region. These odorant substances serve as pheromones which play a role
  related to mating.

Deodorant

  A deodorant is a substance applied to the body to prevent body odor caused by the bacterial breakdown of perspiration in armpits, feet, and other areas of the body.

Can the opposite sex receive pheromones if a person uses crystal deodorant (doesn't have a fragrance; doesn't block sweating; prevents body odor by creating an invisible, protective barrier against odor-causing bacteria)?


texts:
For people with protanopia (absence of "red" cones), confusion lines look like this (which is quite intuitive for me)

Analogous picture for tritanopia (absence of "blue" cones)

  But picture for deuteranopia is quite different. Confusion lines are
  intersecting at one point. But this is not a point nearby green color,
  it is opposite. Why?

I have a conjecture.
Let me remind you about RGB. There is a three-dimensional space (coordinates are RGB coordinates). There is a cone in this space which corresponds to all colors which we can possibly see. Then we consider a section of this cone by a plane. And this is your RGB diagram.

I think that people have chosen a random plane. There is a line for excitation of green cones only. And this the plane intersected negative part of the line. If we chose this plane more carefully, this the picture for green confusion lines would be similar to red and blue.

A friend of mine says that that choice of this plane is not random. It is a plane of constant brightness.
He even conjectured that "green" cone cells are activated not when they absorb green light, but when there is no green color at all.

  Is this plane indeed random?

For more details look up here


texts: I just finished reading J. Craig Venter's book Life at the Speed of Light: From the Double Helix to the Dawn of Digital Life. The book is a little over a year old now, and Venter has an optimistic outlook that bacteriophage therapy will become an effective alternative to gene therapy and viral immunotherapy. He mentioned that the JCVI (J. Craig Venter Institute) is working on such projects. Are other companies also researching, and has progress been made? What are the expected risks? How can rogue, harmful phage mutations be controlled? Can this type of therapy be applied to cancers?


texts: What happens to glucose taken up by the liver in type 1 diabetes?

texts:
Type 1 diabetes is caused by insufficient insulin production.

Unlike in muscle and adipose tissue (GLUT4), glucose uptake by the liver is by GLUT2 and thus insulin-independent. Consequently, under very high blood glucose concentrations, glucose will move by facilitated diffusion into the liver.

However, insulin is not available to stimulate glycogenesis, or lipogenesis; glucagon will be secreted due to high blood glucose concentration, doing the opposite. What happens to this glucose? Does it simply diffuse back out (GLUT2 is bidirectional)? Presumably glucokinase produces glucose-6-phosphate, but the highly controlled points of glycolysis (e.g. PFK-1) will lack stimulation due to loss of insulin. Does a lack of glucagon (due to glucose still reaching pancreatic islet cells, also via GLUT2) have a positive effect?


texts: Does human behaviour that is caused by inheritance depend on the environment and lifestyle in general?

texts:
Different breeds of common domesticated animals such as horses and dogs clearly show different behaviour, instincts, social relationships and similar, due to their biological inheritance. Still they can easily mate with other breeds of the same species. This also applies to wild animals, for example the wolfs living in the rainforest on the Canadian west coast prey on fish (and are maybe expected, with time, to go through a similar transformation as the predecessor to dolphins, that where actually wolf like animals, did when they resettled to the oceans) while inland wolfs prey on moose and elk etc, which requires completely different hunting technique, tactics, pack size and so on.

Are there any similar examples for humans? I reckon that living in the jungle or in the desert or on Greenland should reward different behaviours/traits that influence behaviour. Also going from a hunter-gatherer society to an agricultural society should reward different behaviours, social skills and similar aspect of human life.

Are humans like other animals in this respect (any examples?) or are we unique (?) in the animal kingdom when it comes to the influence of genetics on our behaviour?

One reason I ask is that I got second hand (without sources) information claiming that the natives of Mexico has the highest prevalence, of any population measured, of genes that are known to be connected with/causing ADHD. Mexico was also one the last places on the planet where humankind settled.

The argument went something like this: "during prehistoric time individuals with ADHD tendencies tended to be more adventurous than their peers and therefore traveled further". If this is true, people in Mexico's behaviour should be slightly different from people in current Kenya and Tanzania (by many scientists claimed to the birthplace of humankind), at least if you measure ADHD related traits.


texts: Queller's 1985 version of Hamilton's rule

texts:
Queller 1985 ("Kinship, reciprocity and synergism in the evolution of social behavior") provides a generalization of Hamilton's rule that allows for non-additivity. To accomplish that, Queller writes the fitness of an individual as
\begin{align}
  W = W_{0} - CP + BP' + DPP'
\end{align}
where $W_0$ is the baseline fitness; $P$ is the phenotypic value (1 for altruist or 0 for nonaltruist); $P'$ is the phenotypic value of the interacting individual; $C$ is fitness cost if $P=1$; $B$ is the fitness
benefit if $P'=1$; $D$ is the deviation from additivity of $C$ and $B$ if
both were altruistic (i.e., $PP' = 1$).

Queller then substitutes this equation into Price's equation $\Delta G = Cov (G, W)$, where $G$ is the frequency of altruism allele in the focal individual($0$, $1/2$ or $1$). The resulting equation is:
\begin{equation}
  - \bar c + \bar b \frac{Cov(G,P')}{Cov(G,P)} + \bar d \frac{ Cov(G,PP') }{Cov(G,P)} > 0
\end{equation}
where $\bar c$, $\bar b$, and $\bar d$ are the sample means of $C$, $B$, and $D$.

My question is: how did Queller arrive at the sample means $\bar c$, $\bar b$, and $\bar d$? I understand that $Cov(aX,Y) = a\, Cov(X,Y)$, provided that $a$ is a constant. But what Queller is doing here is different; he seems to be saying that $Cov(AX,Y) = E(A)\, Cov(X,Y)$.


texts: Does iris color effect the amount of light that reaches photosensitive ganglion cells?

texts: Does eye color (of iris) have any effect on the amount of light reaching retina cells and hence effect melatonin production?


texts: I have read that epimysium is dense regular connective tissue made covering the a muscle like bicep brachi. at the same time we have fascia that is made of dense regular tissue and covers muscles. so are they same or different how can we describe it and differentiate it?


texts: What is the connection between sleep requirement and age?

texts:
By this question: Is the human biological clock genetically programmed or learnt? we discussed that the sleep requirement depends on the age of the individual.

- Figure 1. - Sleep requirements by age - ref

I thought I ask the question, why?


texts: What is the anatomical term for a two jointed leg?

texts:
Allow me to apologize in advance for the layman's terminology.

I'm wondering what the anatomical term for a cat- or a goat-style hind leg is.

Cats, goats, t-rexes, and many many other animals don't have human hind legs (i.e., with one knee / one pivot point). They have two pivot points, with one bone going down, then another going back-ish, then another going down again.

I've googled and googled for the answer, but I'm completely at a loss as to what this is called! Is there any name for that style of leg? I'm sure there's a lot of variation inside the category, but there is a category, correct?


texts: Schematic of neural lineage tree and position of Choroid Plexus cells

texts:
I am trying to understand which are the different type of progenitors in the human brain and I am currently following this schematic.

My question is, are Choroid Plexus cells progenitors to Radial Glia (is this paper basically stating that they might work as progenitors)? Otherwise, do they reside out of the provided neural lineage tree? I am aware of their functions related to CSF.

Otherwise, do you have reference papers on neural lineage tree that you can share?


texts: Can a chicken's lard become liquid depending on its diet?

texts:
On Cooking.se, somebody asked a question about the fat in chicken stock sometimes being liquid and sometimes solid once the stock has cooled. The only answer until now suggests that the difference is due to the percentage of saturated fat in the chicken lard, which will vary depending on the chicken's food.

I am not entirely happy with this explanation. I am aware that the proportion of saturated to unsaturated fat in an organism's cell walls will vary with diet, and could imagine that the fat stored within its adipose tissue will be different too. The person who provided the answer also posted references which confirm that part. But I doubt that the effect will be strong enough that, if an animal on low-saturated-fat diet is processed to lard, the resulting lard will be a viscous liquid, as opposed to the usual soft solid. If my memory doesn't fail me, my grandma used to keep her animals on a mostly starch-based diet, and still was able to process them for (solid) lard.

Can somebody confirm or disprove this theory?


texts: My son found this floating in a stream in Massachusetts, in the northeastern US. It was intact when he found it, but he cracked it open to see what was inside. I did some Google image searching, but couldn't find anything. Any idea what it is, and where it came from?


texts: Biological significance of network parameters

texts:
I am currently working on networks and I have calculated various parameters for the network like diameter, average path length, average eccentricity, radiality etc. Could someone guide me to some articles I could read as to what biological significance these parameters hold with regard to a biological network (gene regulatory network). Example, what does a small diameter, radiality etc say with regard to the biological property of the network. On research I could only find one article which could be of some help. Thanks

Edit: I understand that this question has been identified as being too broad but all I require are links to articles that could perhaps guide me to an appropriate solution. Perhaps, the answer can be limited to how does a large network affect a radiality value affect a biological network?

Edit2: Its a cluster from a bigger network, is bipartite in nature, consisting of Transcription factors and genes with a size of 361 nodes. My aim is to check if the clusters are all different from each other and determine if there are significant differences between each cluster. The question was all about what biological inferences can be drawn from network parameters like diameter, radiality etc. For example, a network with low diameter means that network information is passed faster between even the furthermost nodes meaning pathways in that network could have genes with functions that require quick actions, say genes that govern sensory perceptions like reflex actions.


texts: Where can I find the tissue-specific protein expression levels for hTERT (telomerase subunit)?

texts:
I find a number of contradictory sources regarding the tissues in which hTERT - the protein - is expressed. Does anybody know some resource that authoritatively (as authoritative or widely-accepted as is possible) lists the various tissues and hTERT's protein expression levels?

Any similar resource for gene expression of hTERT?


texts: Can anyone please help me identify this plant?

texts: Please help me identify this plant. My aunt had one but it died due to the drought in California. She wants to get a new one but she doesn't know what it's called. The leaves are around two inches and it is seedless, though I'm not sure if it's native in California. Suggestions are welcomed!


texts: Which is the correct statement on proteins?

texts:
I need help with one of the questions on my biochemistry assignment

Choose the correct statement on proteins:
a) proteins are folded by alpha-helix
b) proteins can preserve their function even if they only partially change their shapes
c) proteins are composed of amino acids
d) all of the above

Thanks in advance! :)


texts:
Why is retina transplant not as easy as the normal eye donation and transplant (I think the latter involves the cornea ) ?
This says that a new method has come up but why isnt the process similar and simple as the normal transplant ?
What are the difficulties in retina transplant ?