13
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1answer
246 views

How does herpes (HSV) infection suppress HIV?

HIV compromises the human body to defend against infection. Yet people who are infected with herpes are at less risk of developing AIDS. How does this work?
12
votes
1answer
1k views

Why do neurons die so quickly (relative to other cells) when deprived of oxygen?

This question could be considered a follow-up question to Why is a lack of oxygen fatal to cells?, although the top answer there does not address why damage starts to pop in. The answer says this: ...
11
votes
2answers
2k views

Why don't we develop immunity against common cold?

We all suffer from common cold, and that, frequently. Why have we not developed immunity against it till now? By immunity I mean immunity as a species.
11
votes
1answer
2k views

How does translational coupling work in prokaryotes?

Today I heard about a phenomenon called "translational coupling", where the translation of one protein influences the translation of another protein. The messenger RNA levels don't seem influenced. ...
10
votes
3answers
752 views

The evolutionary process in bird wings, especially with regard to winglets

In this answer on aviation.SE a comparison is made between the shapes of airplanes wings and the shapes of birds wings. It concludes with the following remark: After all, no bird has winglets. Not ...
10
votes
4answers
804 views

“Same” DNA vs genes

It is often cited that humans share 99% (or 98%) of their DNA with chimpanzees. On the other hand it is stated that siblings share only half of their genes. What (if any) is the difference between ...
10
votes
3answers
1k views

How are our senses dimmed during sleep?

Our senses are not as sensitive during sleep compared to wake. There is an arousal threshold during sleep that only when it is overcome will it wake a person up. My question is how is this arousal ...
10
votes
4answers
5k views

How does sodium in one's diet affect blood pressure?

Due to high blood pressure, my doctor has recommended I go on a low-sodium diet. So, that got me wondering what it is about sodium that drives this recommendation? What does sodium do to a body ...
10
votes
2answers
294 views

What can the timing of human urination tell about the human's physical condition and circadian rhythms?

I've noticed a peculiar phenomenon. A subject drinks 400 ml of water, then observes time until the urge to urinate is felt. The time is 15 minutes. The subject releases water. 14 minutes later another ...
10
votes
1answer
161 views

Were dinosaurs 'hot-blooded' or 'cold-blooded'?

Were dinosaurs hot-blooded or cold-blooded? NOTE: The popular term 'hot-blooded' means having an internally maintained average body temperature, which is generally more than that of the surroundings, ...
10
votes
1answer
3k views

Why does Rigor Mortis occur after death?

After someone dies they become stiff, this is termed Rigor Mortis and happens because the cells run out of ATP (I think). But why do the cells need it to remain flexible?
10
votes
4answers
3k views

Why can cones detect color but rods can't?

I don't know if this question applies to only humans but why can cones see much greater detail than rods? Is it possible to have a rod that can detect light intensity and color?
10
votes
2answers
2k views

Why would taking antibiotics increase stamina and energy?

I often hear that people who are taking antibiotics experience wild fluctuations between feeling full of energy and completely alert but soon after feeling impossibly fatigued and sick. Does this ...
9
votes
1answer
88 views

Is our color vision calibrated to sky, vegetation, and blood?

Our color vision is based on three types of receptors (cones) which are sensitive to three distinct locations on the spectrum: 420–440 nm, 534–555 nm, and 564–580 nm. We label them "red", "green", ...
9
votes
1answer
197 views

Why can you not tickle yourself?

It's the age old question, why can't we tickle ourselves? If you rub your fingers along your skin, sure there's sensation but you don't break down into a laughing fit (at least I don't :P), if someone ...
9
votes
2answers
100 views

Is mammalian vision processed as a sequence of frames?

I often read that people believe that human vision has an inherent frames-per-second rate (FPS) that causes stroboscopic effects - such as seeing the spokes of a rotating wheel apparently rotating at ...
9
votes
1answer
122 views

What are the costs associated with carrying lots of genetic material

What are the costs (if any) associated with carrying lots of genetic material (Big genome size)? energy for copying? raw material for copying? space in the cell? Maintenance cost (matter and ...
9
votes
1answer
2k views

How to obtain bacteria samples at home?

As the original question went from hold to closed, I thought I would write up a more appropriate question. How should one go about getting bacterial samples to look at under a microscope at home? ...
9
votes
1answer
198 views

How are new people created from the DNA of an aged person. i.e. Why are we young?

The question "why do we age" has been asked numerous times. But why are we young? The cells of the adult human being are an age (time>0), but how can old cells create new cells that are younger than ...
9
votes
1answer
1k views

How does this illusion work?

I found this image on Google+ If you shake your head you can see a portrait of a person. Can anyone explain how the image is constructed in the brain?
9
votes
1answer
95 views

Relative Property of Alleles

If there are three different alleles to a gene, is it possible that the first is dominant to the second, but recessive to the third?
9
votes
1answer
104 views

Which brain regions are D1 dopamine receptors expressed, and which brain regions are D2 dopamine receptors expressed?

This is a follow-up question to If D1 receptors stimulate adenylate cyclase (through GPCRs) and D2 receptors inhibit it, then why do mutations in both have similar effects?. As a further question - ...
9
votes
1answer
116 views

Why is there an extended delay before G.M. liver cells are attacked by the immune system?

In this BBC article a trial is described where patients with B-Haemophillia are infected with modified Adeno-associated Virus 8 which contained the genes for Factor IX clotting protein. Trials seemed ...
8
votes
1answer
143 views

Model for fluctuating selection

Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale? For example, let's consider the bi-allelic gene A, with alleles ...
8
votes
2answers
330 views

What is the smallest molecule that can present as an antigen to the immune system in the context of allergies?

People often claim, in a colloquial sense, that they are "allergic to everything". Is it possible to have a full-fledged IgE mediated allergic response to very small molecules? I was always under ...
8
votes
1answer
370 views

Has any large-scale origin-of-life simulation/experiment been done?

I have been thinking a little about the origins of life, and was further inspired by this question: How did the first self replicating organism come into existence? I can accept that we don't quite ...
8
votes
2answers
1k views

How much weight/volume do microbes occupy within the human body?

Microorganisms constitute the bulk of all the biomass on Earth. I weighed myself yesterday, and wondered how much less I would weigh if I were completely free of bacteria and microbes, inside and out. ...
8
votes
2answers
30k views

Which shades/hues of color are easiest to distinguish for humans?

I'm trying to represent data graphically and am using a variation of hue/lightness to distinguish one data point from the next. I would like to use a color that would allow me to convey most ...
8
votes
1answer
215 views

Why does the gender of the parent species determines the species of a hybrid offspring

I've read a little about hybrid animals, and have been amazed by the fact that the gender of the parent species determine the species of the offspring, in some hybrids. A male horse and a female ...
8
votes
1answer
2k views

What hydrolyses aspirin within the digestive tract and blood stream?

I have had some further thoughts after my previous question regarding the buccal delivery of medication. The active compound in aspirin (acetylsalicylic acid or systematically 2-Acetoxybenzoic acid) ...
7
votes
1answer
67 views

Hamilton's derivation of direct fitness from his 1970 paper

In his 1970 paper "Selfish and Spiteful Behaviour in an Evolutionary Model", Hamilton uses Price's equation to derive his well-known rule $rb -c >0$. My question is about one of the steps in his ...
7
votes
3answers
978 views

What is the science behind the inaccurate perception of colors?

If I go into a green room (all walls are semitransparent and green) and spend some time - around 10+ min - in there, when I come out all my eyes see is white as pink. I see no (or very few other) ...
7
votes
1answer
906 views

Why does A pair with T and G with C?

DNA is made up of pairs on AT and GC base pairs. I know that A only pairs with T and G only with C. Does this apply just to humans, or are there animals where T will pair with G? Also, surely there ...
7
votes
1answer
208 views

How do I read a sequence logo?

I'm looking at a paper that uses several sequence logos to illustrate the consensus sequence of certain sites. Here is the most important of the sequence logos I'm interested in: The explanations ...
7
votes
3answers
304 views

Can genes change as we age?

Let's say you're a 23 year old man who impregnates a woman. Will your genes be the same if you were to impregnate another woman at age 35? Will your genes in those 12 years have ...
7
votes
2answers
165 views

The Assumption of Weak Selection?

I was reading this question and I failed to fully understand the introductory part of it. The OP (@Artem Kaznatcheev) says: Most analytic models like to assume weak selection because it allows ...
7
votes
1answer
154 views

Can cancer cells in the same person, organ, and origin have different DNA?

Is it possible for cells from the same tumor to have different genetic material, and if so, to what degree is it possible (how fast do they mutate) ?
7
votes
2answers
5k views

What determines if a gene is dominant or recessive?

Going back to my high school days we were taught about dominant and recessive genes. We were taught how to calculate the geneotype and pheneotype of potential offspring using a small table (forgotten ...
7
votes
2answers
205 views

Could cancer be in itself a evolutionary process?

Could cancer be in itself a evolutionary process? Maybe in some way could it be a process of variation? Or would this idea be completely without support, if so, why? I don't mean that each case ...
7
votes
1answer
536 views

How is the exogenous DNA protected from degradation during bacterial transformation?

During transformation, a bacterium can take up DNA from its environment. A small fraction of bacterial species are known to be naturally competent, meaning that they can engage in this sort of ...
7
votes
3answers
757 views

Finding proteins in DNA sequence

I have to do a task for a university task and I need to understand some things before figuring out how to do it. The task is the following: Find matches of known proteins (DNA-PolyI,II,III) to ...
7
votes
1answer
269 views

Recombinant protein fraction in E. coli

If a protein is heterologously expressed in E. coli under the T7 promoter, what fraction of the total protein concentration in the cell is the heterologously expressed protein? What could be its ...
7
votes
2answers
244 views

Does becoming martyr have an evolutionary advantage?

This is related to How does "be altruist to those who are similar to you" evolve? Altruism that is Not reciprocal Not familiar has little explanation. One possible explanation is that ...
7
votes
1answer
193 views

Decreasing the alcohol proof and faster in hangover, why?

My russian friend says that the USSR agents used/use the trick that they offered the victim first vodka and then last wine. I have noted that this puts you faster to hangover: decreasing the alcohol ...
7
votes
1answer
601 views

X chromosome “weight”?

According to Wikipedia, the X chromosome has approximately 153 million base pairs, while the Y chromosome has only 60 million base pairs. Thus, the difference is roughly 93 million base pairs. My ...
7
votes
2answers
997 views

How does an inhibitory synapse communicate to the cell body of a neuron?

I picture a neuron as having multiple trees of dendrites attached to the cell body with a single axon leaving the cell body. I believe the cell body near the axon root makes the decision to fire or ...
7
votes
1answer
3k views

The effect of the start codon GTG on translation in E. coli

Translation in E. coli is initiated at the start ATG codon, which encodes for the amino acid Methionine (Met). In some cases, the start codon can be GTG, which within the open reading frame (ORF) ...
6
votes
1answer
114 views

How much total RNA can be extracted from Drosophila brain

I am wondering how much total RNA could be extracted from a single D. melanogaster brain. I could not find this information from the literature. The closest hit was this paper, that claims that ...
6
votes
2answers
134 views

Advantage of opponent color?

Opponent process is a color theory that states that the human visual system interprets information about color by processing signals from cones and rods in an antagonistic manner (source). What is ...
6
votes
2answers
145 views

What does pain look like in wave form?

I am interested in understanding what "pain" and "hot/cold" look like, as far as waves signatures (signal processing) go. My general understanding of how pain (nociceptive pathways) and hot/cold ...

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