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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2answers
98 views

What makes something food?

From my (limited) understanding, animals get energy from food by breaking chemical bonds between molecules. There's a lot of water here [citation needed], so it seems like natural selection would ...
3
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1answer
74 views

Why cold water results in cough [closed]

I have a pretty simple question which always kept me intriguing since childhood and I couldn't find its precise answer yet. Why do we cough by cold water. Recently I had flu and found very strange ...
3
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0answers
43 views

What happens to the brain during sleep versus unconsciousness?

How does being unconsciousness differ from being asleep and whether it causes breaks in consciousness?
3
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1answer
97 views

How two genomes adopt when cell goes to recipient's body from donor's body?

We often give blood to another following the blood giving compatibility chart. Heart transplant and similar transplants also brings one's cell to another's body. My curiosity is, when a cell goes to ...
0
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1answer
30 views

Does mechanotransduction of cells play a role in the biocompatibility of titanium?

What exactly is mechanotransduction as the information varies between sources. Some sources indicate that mechanotransduction is the underlying principle where cells pull on the surface they grow on ...
0
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1answer
59 views

Evolution to store limited Fat

Why are our bodies not evolved to store only limited amounts of fat, which won't kill us with all diseases associated with obesity? Wouldn't obese people die faster and clean the gene pool for people ...
3
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2answers
135 views

Does sweat contain DNA information?

I was reading this article : Perspiration The first question which came to my mind after reading the composition of sweat was whether it contains any information about the DNA or not? I haven't had ...
0
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0answers
10 views

Cellular aspartate level?

I know that aspartate is a product of urea cycle, gluconeogenesis and oxaloacetate. In addition, there are dietary sources such as meat and vegetables. I would like to know what are the other factors ...
0
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0answers
60 views

Why is my right hand's thumb on the left side and my left hand's thumb on the right side?

My daughter just asked this question, and I could not provide a thorough answer. My first speculation is that it allows one to manipulate an object using one' both hands simultaneously (if the thumbs ...
-1
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1answer
74 views

Is it possible to grow a fertilized human egg entirely outside the woman's womb?

Many science-fiction movies show the possibility of growing a newly fertilized human egg entirely outside the womb of the woman. This means that you have to create the exact circumstances for the ...
10
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2answers
1k views

Why do Hot/Cold drinks taste sweeter once returning to room temperature?

Now, I know this is a very bizarre question, and I tried to find a correct exchange for this, but it might relate to biology/science as it being our taste buds and everything. I am so sorry if there ...
1
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2answers
68 views

Does night sleep provide more energy-regain than sleep during the day? [closed]

After reading this, I know that sleeping is an universal function, and that basically everything with a brain has the need to sleep. However, I am still confused to what extent it is necessary to ...
0
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2answers
65 views

What physical traits are derived from the Neanderthal DNA in human DNA?

Some researches had found that Human DNA has a bit of Neanderthal DNA. So they suggested there would have been crossing between Homo sapiens and Neanderthals. Now the Neanderthal looked a bit ...
3
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1answer
2k views

Does a woman contain all the genes needed to make a man?

I know the answer of inverse is at here, but how about this question? I also read this question, can I imply to human that a woman can also contain all the genes needed to make a man? Edit: I ...
1
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0answers
21 views

How much yogurt would one have to consume to have a noticeable effect on neurotransmitters [closed]

I read several recent articles that proposed a link between bacteria in our gut and neurotransmitters in our brain. For instance http://www.ncbi.nlm.nih.gov/m/pubmed/24997036/ I am curious how much ...
1
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0answers
24 views

How do I “reinoculate” a petri dish with new bacteria?

Hypothetical question, intended to find a general procedure rather than case-specific recommendations: I have a petri dish full of growth medium with a large population of gram-negative, anaerobic ...
0
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0answers
12 views

How large are medullary thymic epithelial cells in volume?

I'm looking for a rough average volume of medullary thymic epithelial cells (mTECs/MECs) in humans and mice. It would also help to know how they differ in form (are they spherical, long stretched, ...
0
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0answers
18 views

Relationship between Human Sleep Cycles & Sunlight

What is the relationship between the human sleep cycle and Sunlight? Why do humans tend to sleep for longer hours during the night than the day. Since we rely on Artificial lighting during the night ...
1
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0answers
52 views

Why is a wound much more painful when damp?

Why is a wound much more painful when damp? This is a very strange phenomenon. For example: I have a little wound, not painful at all. But, when it is just damp, it is much painful.
2
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0answers
44 views

Are all the atoms in your body replaced with others over a 30 year period?

I was reading Creation - Life and How to Make It by Steve Grand. (This is the book that inspired Jeff Bezos to start the AWS initiative. ) In it he makes the following statement: Anyhow, by now I ...
1
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2answers
14 views

Do Class A biosolids count as organic fertiliser?

Does Human Waste, which has been treated at least twice to remove pathogens & remove stink, still count as organic despite it passing the EPA's class A standard? If so, does this mean that none-...
0
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2answers
82 views

Use of sunlight in biological processes

Sunlight is used by green plants in photosynthesis, but it is also used by animals in the synthesis of Vitamin D. Are there any similarities between the two processes and how is the light energy ...
0
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0answers
16 views

Is it true that our tooth enamel shows a 7 days rhythm?

Is it true that in fossil remains of the Turkana Boy a kind of growth rings are found in tooth enamel which have a rhythm of a week? This also appears to apply to other primates? If so what is the ...
2
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1answer
64 views

Fasting gastric pH versus normal gastric pH

I want to know if someone is fasting (no food or drink for a whole day) will they have a higher or lower pH than a person who is eating regularly? If so what is an estimate of both of those pH's in ...
0
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1answer
170 views

If human proteins are synthesized from only 20 different amino acids, then how can there be such variety of proteins in human cells?

I know that human proteins are synthesized using only 20 different amino acids. However, how can there be thousands of different proteins in human cells, if we only use 20 amino acids to make them?
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0answers
23 views

Are there biological safeguards to compensate for male primate infertility?

I'm trying to understand human sexual selection, and the following question has been on my mind for some time. I don't know the exact terminology to do a quality scholarly search on the subject. Are ...
1
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1answer
44 views

Why does the blood not clump and result in death?

In this question's accepted answer, it is said that the blood type will slowly change to that of the donor's. When the blood in the person is about 50% his own and 50% that of the donor's. i.e, 50% A ...
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0answers
20 views

What kind of cell has the most different receptors?

All hormones and neurotransmittors has their own receptor. Now some of the cells has a few different receptors but others has many sorts of receptors. So what are the most receptive cells? Are that ...
18
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2answers
958 views

What is the cause that angina pectoris is felt in your left arm?

When someone has heart problems sometimes they feel pain in their left arm. But why is the left arm painfull?
6
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1answer
77 views

Why is there no symmetry in pigmentation when comparing people north and south of the equator?

If you are at the equator and start moving north, the further you travel, the lighter the skin of the indigenous peoples. Considering that we live on a ball, why do we not find the same traveling ...
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0answers
37 views

When touch and pain are caused by heat/cold or pressure how are the nerve cells triggered?

I suppose that when your skin is smoothly touched by any cold/heat or pressure we feel that because our AB cells notice this due to a kind of change in the nerve cell. But when you touch something ...
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0answers
14 views

Does the change in eye color (melanin concentration) affect the iris pattern?

In cases of acquired heterochromia, is there a quantifiable change in the iris pattern; the clefts , furrows, etc. If yes, what changes are observed? And if no, are there any diseases or acquired ...
5
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1answer
59 views

If our skin is burned by the sun what causes the red color of the skin?

Mostly it is not a good sign we are burned because too much UV light has damaged our skin and increases skincancers. But the red color we get after a few ours, what is the exact cause of it and why ...
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0answers
21 views

Anaerobic nutrient expenditure

Doing some research into different forms of exercise and energy systems and I realized something odd about the way we talk about energy. When we eat, we take on macronutrients that are broken down ...
0
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1answer
36 views

the evolution of the human brain size [closed]

I was thinking, as I know, sometimes the process of producing DNA did not work well(correct me if I'm wrong), so it gives us some changes in the object we gonna ...
12
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2answers
172 views

Can viruses be toxic?

Bacteria can produce toxins like endotoxins and exotoxins. In diseases like cholera or tetanus they can harm infected people due to these toxins. Now, although viruses are much smaller and are ...
8
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1answer
130 views

Does our immune system react on all bacteria?

In our body we carry a lot of bacteria. Some of them are bad for our health, but others are beneficial. For example bacteria may protect us against other pathogenic bacteria. But is our immune ...
14
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1answer
954 views

I don't want to know what bacteria is called but if the bacteria from unborn babies have benifits on health? [duplicate]

This question is not the same as the duplicate. I was told that when babies are born they are born with bacteria in their stomach. When a child takes antibiotics are there unique bacteria destroyed ...
1
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1answer
44 views

Does a zygote express all genes?

If a zygote has all the cytoplasmic determinants and all the specific transcription factors, does that mean that all genes in the genome are expressed?
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0answers
40 views

Is the zygote the only totipotent cell?

I’ve been told that the unfertilized egg contains cytoplasmic determinants (e.g. proteins, transcription factors, mRNAs) that are divided unevenly during the early stages of cell division in an embryo....
5
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0answers
54 views

Are high sounds worse for your hearing than low sounds?

From about 80 dB it is possible to suffer loss hearing after a couple of hours. But does it make a difference what frequencies those sound waves are or is it just the volume of the sound in dB that ...
5
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0answers
121 views

What will happen when humans are injected with plant growth hormones

Will plant growth hormones (PGHs), (let us consider auxins for example) poison our body or not? I do realise that when you eat a shoot, auxins get digested and are less likely to be poisonous but when ...
8
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0answers
70 views

What Would Happen To a Human Who Died In Space And Stayed There For a Prolonged Period of Time? [closed]

Last night I was watching a documentary regarding the Apollo space program, and it spoke about how Apollo 8 orbited the moon 10 times then came back to Earth. It said that while the ship was in orbit ...
7
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2answers
80 views

Do babies conceived naturally or artificially have any differences in long-term health?

Are there any long-term differences in children conceived via artificial insemination or sexual intercourse, pending that the mother successfully delivers the child?
0
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0answers
36 views

Do both the Sperm and Egg must be at exactly 7.4 pH for fertilization?

I suddenly came across this article and it says that for human conception to occur both the sperm and egg must be at exactly 7.4 pH - not 7.0, nor 7.7 but 7.4. If conception depended on such exact ...
3
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0answers
37 views

Are all genes transcribed in differentiated cells?

My textbook tells me that it’s specific transcription factors that allow for a different set of genes to be expressed in different cells (differential gene expression). My book gives the example of ...
22
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2answers
2k views

Why is it advised that infants are fed mother's milk?

I have heard that mother's milk is preferred over other baby foods, because it contains immunoglobulines (secretory IgA), and other essential nutrients. But why is mother's milk so special? Any ...
6
votes
1answer
60 views

Is Zika suspected of causing birth defects only if contracted during pregnancy?

There seems to be growing evidence that a recently spreading strain of Zika virus is in fact linked to microencephaly and other birth defects in newborns (see here, here, and here for examples). I ...
5
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1answer
102 views

Why is it always Sodium that we talk of in blood pressure?

Why is that we emphasize so much on sodium in blood pressure? I understand that it is a major extracellular ion, but, it also is tightly regulated. So when something is that tightly regulated, won't ...
1
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0answers
38 views

Why are oral cells (or tissues) more heat resistant? [closed]

When we are having meals, such as enjoying hot pot and drinking hot water, we only have a sense of "warm" in our mouth, or even along the organs in alimentary canal. But when we put our fingers into ...