This tag is for questions about the general biological features of human beings (as opposed to the biology of non-humans).

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Marker validation using transcriptome and genomic sequences derived from a single cell

I conducted a SSR marker analysis using bioinformatic tool on some RNA-seq data of human tissues. Now, my supervisor believed that we have to validate theses SSR on a transcriptomics and genomic ...
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9 views

Why do we stop growing even if our cells continue to divide? [on hold]

Why do we stop growing after a certain age while our cells are still dividing?
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16 views

Do we all dream “every” night?

I had an argument with my brother and he claims that he doesn't dream every night ie when he dreams he always remember and if not he hadn't dreamt at all. I'm under the impression that all humans ...
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11 views

Proteins denaturation and natural selections

Which are the advantages, in terms of natural selection, of the denaturation of the proteins during the food preparation? Or in other terms, is it more important the reductions of bacteria in the food ...
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1answer
38 views

Why do men grow facial hair?

Ancestral facial hair. Our closest ancestors, the chimpanzee and bonobo, both grow facial hair around the mouth area. What is noteworthy is that this is the case in both males and females of the ...
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11 views

Why does anaerobic microorganisms cause fetid smell in respiratory secretions? [on hold]

This is always given as a fact. But I've always wondered about the reason.
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2answers
402 views

Why can humans feel electricity?

What evolutionary process has provided humans with the ability of feeling electric current? Besides lightning and electric eel, what natural hazards include electricity that poses a threat to humans? ...
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37 views

Why do we turn darker in the sun?

I tried the all powerful google to answer this question - but I am not getting the answer I seek. I know we turn darker because the skin produces melanin. The question remains - why darker? I am a ...
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Can one mother have a white and black baby twins? [on hold]

I was reading a news and found that one American white mother had two babies out of which, one was black and other was white. The mother was demanding that both of the children were her but the ...
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How late in a human pregnancy can a zygote split?

This page indicates that the first two days is "very early" for a zygote to split, and that conjoined twins are the result of an "extremely late" split: If the zygote splits very early (in the ...
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2answers
48 views

Can the human body enter “Power Save” mode? [on hold]

Once a year, I am fasting for 24 hours. No food or drink at all for whole 24 hours. Recently I thought about what is happening to me during those 24 hours, and realized there might be something ...
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3answers
491 views

Why we do not get hurt from HCl secreted in the stomach?

I read in my book that during digestion our stomach secretes hydrochloric acid ($HCl$). Why we do not get hurt from it? It was also said that mucous provides protection, but from where is it coming?
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56 views

Genetics and Evolution [on hold]

why do we have a nictitating membrane in our eyes ? What evolutionary relationship does our nictitating membrane provide about ous ?
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1answer
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Cancer in myogenic heart cells?

Why cancer does not occur in myogenic heart cells? Is there any special ability in heart cells to resist cancer ?
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46 views

Why do most humans like to swim? [closed]

Why do most humans like to swim (at least they who can swim) and generally be in the water? We are land living animals with no specific attributes or features to ease being in water (at least not more ...
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3answers
71 views

Why didn't humans evolve to reproduce identical twins all the time?

According to the selfish gene theory, it seems like because identical twins sometimes get produced, a mutation to a gene that says, "if you have an identical twin, be fully altruistic towards them" ...
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30 views

Proteins and Blood Acidification

Is there evidence to suggest that excessive consumption of Whey, or similar proteins will lead to acidification of the blood?
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1answer
61 views

Why do sneezes come out the mouth?

As anyone who's ever sneezed can tell you, it's caused by irritation in the nose. And the answer to a question on this very SE attests that "sneezing is a reflex, partially autonomous, to clear the ...
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55 views

Why do girls/women grow facial hair? [closed]

People say they don't but they do. If you look closely, most females have small hairs all over their faces.
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2answers
32 views

How can a chromosome translocation in somatic cells lead to disease?

Looking at this picture... ...I get the impression that the part of chromosome is attached to other chromosome, but it is not mutated. When we assume that all genes in the translocated part are ...
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1answer
49 views

Cut strand of hair longevity?

Quick and useless question : what can be the longevity of a cut strand of hair, assuming we kept it in (good) normal conditions ? Any idea ?
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How does drug-induced photosensitivity work?

Some drugs (tetracyclines, for instance) can cause photosensitivity reactions—that is, some patients become extremely sensitive to the sun, developing rashes or inflammation after spending time ...
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1answer
30 views

Does alcohol really do more damage to the body of a child compared to an adult?

Beside the fact that children and teens (people under the age of 18 year) usually have less body weight than the average adult, is there a biologically fundamental difference between the damage done ...
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1answer
43 views

How long do human egg cell grow up?

I read article about alcohol harm where written that child may bear with birth defect cause mother used to drink alcohol 10 years ago so egg cell stay damages that long. I don't believe that human ...
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0answers
23 views

Why does our body exhibit bilateral symmetry? [duplicate]

Externally, we (humans) look symmetrical. However, internal organs don't show the same patterns of symmetry (heart being on the left side while the liver is on the right side, etc.). It is a bit ...
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What is the lifetime of the vasopressin receptor V2?

I was looking at the production of vasopressin receptor 2, also known as V2R or ADH-R. What I found is that it is coded by the AVPR2 gene and degraded by the Alix protein (source). But I did not get ...
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1answer
163 views

How to identify the age of a “living” person?

Different people may age differently. A 60-year old person may appear to be 80, while somebody else could appear younger than their mathematical age. Some other people may have progeria. What is ...
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74 views

Why do people die? [duplicate]

what is the reason people die naturally even though they have no known disease? I see people become physically weak at times they get old and die eventually in case they are not attacked by any known ...
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1answer
88 views

Will a 0.2g/mL sugar concentration cause vomiting in humans?

This infographic claims that the sugar content in a can of Coca Cola would cause vomiting if not for the phosphoric acid. In The First 10 minutes: 10 teaspoons of sugar hit your system. ...
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Why does a limb sting when it “falls asleep”? [duplicate]

Closely related to this question, but unanswered other than @Matthew-piziak providing a description and link that says: What is Paresthesia? Paresthesia refers to a burning or prickling sensation ...
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1answer
54 views

Can my eyes adjust instantly to my friend's glasses? [closed]

My eyesight is pretty much perfect, but I noticed that whenever I try any of my friends glasses, from really thin to extremely thick, my eyes seem to adjust to them within seconds and let me see ...
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2answers
49 views

Bernoulli’s Principle in the Cardiovascular System

Below are graphs which illustrate the cross-sectional area, velocity, and fluid pressure through each vascular segment of the cardiovascular system. It makes sense that velocity and cross-sectional ...
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1answer
69 views

Is there a schema for how human behavior is genetically determined?

It seem one can distinguish three different kinds of genetic determinism of common patterns of human behavior: behavior that is directly wired into our nervous system, e.g. face-related mirror ...
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1answer
78 views

What bacteria do unborn babies contain?

This Scientific American article states that "[human] infestation [by bacteria] begins at birth". This would suggest that unborn babies are free from any bacteria. However, if the mother catches a ...
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1answer
34 views

Do the enzymes and compounds in saliva help with stain removal?

Does spitting on stains help with removal? Saliva is high in amylase that should help with the breakdown of protein rich stains like blood and semen. It also contains antimicrobial enzymes and ...
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0answers
47 views

How long does conception take?

I know that conception is a multi-step process. A sperm fuses with an egg. Its contents diffuse into the cytoplasm. Dad's DNA is transported to the nucleus. Proteins are gradually made from Dad's ...
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2answers
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What would happen if brain neurons did not reduce their sensitivity to neurotransmitters after prolonged exposure?

From my understanding, neurons decrease their sensitivity to neurotransmitters by reducing the amount of receptors on the cell membrane in response to sustained neurotransmitter activity. One ...
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62 views

How to mimic / approach some animals/insects' anabolism?

This article states that some shelled animals - spiders, scorpions, crabs, worms and other creatures - have metal atoms in their claws, jaws and fangs. I believe through anabolism, since they eat ...
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1answer
89 views

Do our belly buttons consist of scar tissue?

I read an interesting post on Facebook the other day saying that we all have a visible scar since birth - our belly button. This got me thinking (and research for me only found results regarding belly ...
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36 views

Is there a mechanism by which mammals lose interest in a partner after mating?

I'm reading the book called "Cupid's poison arrow", which revolves around a rather simple assumption: most mammals, including humans have a genetic program that is responsible for ever increasing ...
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23 views

Why are humans mostly right-handed? [duplicate]

Most sources I've seen say that about 90% of humans are right handed, and 10% are left handed. Why is this? My only guess would be that it has something to do with different parts of the brain ...
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1answer
65 views

Is each generation getting older? [duplicate]

So we know that our sperm and egg cells get set aside relatively early so that they aren't going through unnecessary cell divisions and causing DNA damage or telomere shortening, but since each new ...
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2answers
736 views

Why does mouldy food make you sick?

Bread gets mouldy pretty quickly, and my parents (both of whom are nurses) throw out a loaf of bread after a spot of mould is seen (because "if you can see one spot, it means the whole thing is ...
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1answer
34 views

Why is there a compound highlighted in red in a KEGG Module search?

Considering the following module: http://www.kegg.jp/kegg-bin/show_module?M00115+C00003 why is the compound C00003 marked in red?
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112 views

Which of these methods is both effective and reliable in elongate muscle and tendon for use in humans: growth factors or stem cell technology

Which method is it the most effective, but also the most reliable for elongating muscle and tendons for clinical trial; using modern growth factor technology or using modern stem cell technology? ...
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1answer
14 views

What information does the KEGG Module statistics page show?

While browsing through the home page of KEGG Module, I clicked the button named Module statistics. Can someone tell me what does these numbers signify? What are they the statistics of?
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1answer
40 views

Would a human survive eating only living ants?

After reading an admittedly foolish question about 1 googol ants vs. 1000 humans, I had a question. Could a human survive solely on eating ants (common ants, not the stinging kind, or leafcutters ...
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2answers
56 views

Why are our bodies created to itch when histamine is released by our immune systems?

Why do bug bites and cuts itch when scratching them clearly doesn't help us survive? Did our early ancestors need to rely on this itching sensation, or is it just that the receptors for itches just ...
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1answer
64 views

What are the most important factors influencing a person’s gut microbes?

You are your bacteria! The probiotics and the antibiotics... There has been on going discussions about how our gut bacteria is important for a healthy lifestyle. Figure 1: Schematic diagram ...
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3answers
112 views

Blood urea nitrogen and usage of proteins?

I have been reading some books and am getting slightly confused. Here is roughly what I have read. The greater the blood urea nitrogen the greater the usage of proteins (since blood urea nitrogen ...