Questions tagged [human-biology]

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

Filter by
Sorted by
Tagged with
3
votes
1answer
121 views

Why do we need to amplify DNA sequences?

I am learning about biotechnology. I have no education in biology or chemistry and am simply interested in the subject of biotechnology. I am wondering why we need to have multiple copies of a piece ...
1
vote
1answer
143 views

Sleep deprivation relation to growth rate and mental health in adolescence

Do sleep deprivation and its timing affect growth rate and mental health in adolescents? If so how much sleep is enough for teenagers?
-1
votes
1answer
51 views

Why males are more prone to cardiovascular diseases such as heart attacks than females?

I often see more people of males undergoing treatment for heart disease. It is often said that female reproductive hormone (oestrogen) has some cardio-protective action by preventing constriction of ...
-1
votes
1answer
805 views

What happens if an enzyme stops working in the body?

For example, if the enzymes in the digestive system stop working will the digestion still occur as enzymes are only catalysts for the reactions. Thank You
2
votes
1answer
38 views

By what mechanism do our nerves lengthen as people get taller?

How do nerves get longer as kids grow taller? I searched for an answer but I can only find information on the formation of nerves in embryos.
0
votes
3answers
112 views

Are there any proteins not found in the brain that are affected by prions?

A prion is an abnormally folded protein that is capable of causing otherwise normal proteins to also misfold and become prions. They are responsible for causing diseases such as Kuru and Creutzfeldt–...
0
votes
0answers
56 views

Human femur maximum strength

In this video https://www.youtube.com/watch?v=os98s9kBlOI it is demonstrated that a moose leg bone can support until nearly 10 tonne before break. Is there any similar demonstration on human femurs? ...
1
vote
2answers
256 views

Why isn't life expectancy normally distributed?

Lots of phenomenon in nature can be plotted onto some sort of normal distribution, and that makes intuitive sense to me (such as human height). Why then, does global human life expectancy drop off so ...
1
vote
2answers
153 views

Are there any benefits/disadvantages/traits from having a permanent lower core temperature?

My body temperature as far as I remember has always been around 35.6 degrees Celsius, that's a degree less than what is the usually quoted as the average temperature for humans. Are there any known ...
1
vote
0answers
38 views

Does intelligence depend more on environment than on genetic factors? [duplicate]

Many have argued that the test of IQ is simply a test of language. The application of the test consists of asking a number of questions. The person should understand the question presented to them and ...
1
vote
0answers
45 views

How much Oxygen can the Human body carry?

Basically - the title: How much Oxygen does a human body carry at a single point? What have I tried: A friend of mine has done some calculations and came up with the following numbers. Neither of us ...
1
vote
0answers
43 views

Is it possible to buy a DNA sample with a specific mutation?

I would like to test a genotyping method (ARMS) on a specific human snp (heterozygous or homozygous ). Unfortunally, we do not have any dna samples with the mutation. Is it possible to buy somewhere a ...
5
votes
1answer
72 views

Can stress and arousal be independent?

I'm trying to figure out if it's possible to have a stress response without being initially, or simultaneously aroused. I'm defining stress to be physiological stress (ie. release of cortisol) and ...
1
vote
0answers
36 views

Could ions inside lungs produce hydroxyl?

I am not proficient in either biology or chemistry. However, I have a question which I can't find answer to. It seems to belong somewhere between chemistry and biology. I apologize for any errors and ...
1
vote
0answers
35 views

Can we “learn” reflexes?

Can we force our bodies to react to situations faster than our brain can think about them? Some reflexes I can think of off the top of my head: knee jerk reflex retracting hand when touching a hot ...
0
votes
1answer
72 views

Does the 1:1 sex ratio at birth apply to every human pregnancy or is it a statistical average?

Are there genetic factors that biase the sex ratio of offsprings for each person but average to 1:1 for the entire human population, or does the 1:1 ratio apply to every single fertile person?
2
votes
1answer
76 views

What do we mean by MHC molecule diversity? Does each human have a variety of MHC molecule isoforms?

I'm going to try and explain what I think I know From what I understand, MHC/HLA molecules present peptides to T cells. To be able to present peptides from a wide variety of pathogens, they need to ...
14
votes
2answers
2k views

Can UV radiation be safe for the skin?

It is well known that UV radiation can damage the DNA and generally harm our skin. We also know that UV radiation helps on the production of melanin and Vitamin D. From what I could find, the DNA ...
4
votes
1answer
139 views

Does body absorb nutrients less efficiently if we ingest the same amount at the same time, opposed to spreading over a larger period?

I would like to understand if ingesting a certain amount of nutrients will result in different absorption from my body, depending on whether I ingest that amount spread over time or everything at once....
1
vote
0answers
71 views

What are the sufficient criteria that make an entity a living homo sapiens? [closed]

When I say criteria I mean like x biological functions or y genetics. If it were to be appearance,anatomy. A corpse completely looks like a man. Moreover a person who has had their 4 limbs amputated, ...
1
vote
0answers
51 views

Why do I have 95% of chimpanzee's DNA, and only 2% of Neanderthal's DNA? [duplicate]

Excuse me if it is a question with a simply answer, but I don't understand these discoveries, looking a discrepancy from my unknowledge of genetics: I have 95% of Chimapanzee's DNA, and, I have [...
4
votes
2answers
110 views

What could humans do to “see” what dogs smell?

We're able to see a lot of things using computers that we can't see normally: yellow-green, UV light, X-rays, etc. What do we have that harnesses the ability to "see" what dogs smell (e.g., harnessing ...
0
votes
0answers
34 views

How does the cardiovascular system improve upon repeated, strenuous exercise?

New here, hopefully this is the right place to post this question. It's widely known that repeated, strenuous aerobic exercise gradually improves the capacity of one's cardiovascular system — $\text{...
1
vote
1answer
315 views

Are casein proteins in UHT milk digestable for infants or toddlers?

As a novice cheesemaker, I have read that Ultra High Temperature prosessed milk is unsuitable for cheesemaking, as casein proteins are denatured and cannot be curdled with rennet. I have verified that ...
-6
votes
1answer
132 views

What separates humans from other animals?

It is clear that humans are distinguished from the other species on Earth, but what specific features are the cause? Other animals like chimpanzees have been shown to have consciousness and some self-...
1
vote
0answers
50 views

Which chemokines are being produced by melanocytes?

I am looking into Vitiligo it's an autoimmune disease that results in apoptosis of melanocytes due to misfolded protein accumulation. It also dramatically increases breast cancer rates (600 times) ...
1
vote
1answer
49 views

Why can early embryos survive freezing?

According to this Blastocyst & Embryo Freezing in IVF Embryos can be frozen at the pronuclear stage (one cell), or at any stage after that up to and including the blastocyst stage (5-7 days ...
-2
votes
2answers
126 views

Why isn't the human zygote considered a human life how is a living anatomically modern human defined biologically? [closed]

It has 46 chromosomes by default when healthy(Differences almost always are pathological) and has almost every biological functions, processes a Newborn or and Adult person has. It even invades ...
3
votes
1answer
284 views

Cerebral/Cerebellar Cortex versus Deep Nuclei

I have troubles using the terms Cortex & Deep Nuclei, and 'Nuclei' in general. From what I understand, a brain has '3 matter types in accordance to anatomical locations' Superficial Grey matter - ...
-1
votes
1answer
57 views

Sexual Reproduction in Humans

Is the human egg cell (ova) considered motile? We know that is is not actively motile but it is transferred via the fallopian tube to the uterus. Does that make it motile?
0
votes
1answer
31 views

Protein inhibitory process

I usually find substances that activates proteins, like ApoA-I, but I don't find substances that inhibit it. So in an experimental design, could I consider the absence of a drug that directly acts ...
3
votes
1answer
116 views

What is a deep exhalation/inhalation?

I tried to find the academic definition of deep exhalation/inhalation but found nothing special. I speculate that the correct definition is as follows: • Deep ...
1
vote
1answer
58 views

Are your finger muscles and tendons interconnected?

Are finger muscles and tendons interconnected? If they are interconnected, then if i exercise one finger will it train the other fingers since they are interconnected and share the same muscles in the ...
4
votes
0answers
67 views

Optimal carbon dioxide concentration range for the human body

Previously I had thought the maximum concentration of CO2 for human health to be given by the ‘Pettenkofer CO2 level’ with a maximum of 1000 ppm. But according to this post a growing body of ...
2
votes
1answer
45 views

RE: Fasting gastric pH vs Normal gastric pH

If fasting gastric pH values are more acidic then why is it recommended to eat no more than three hours before bed time to prevent reflux. It seems at some point during sleep the stomach would become ...
0
votes
1answer
85 views

Does vitamin D affect melanin concentration?

I am aware of the affect on vitamin D production by melanin (in sunlight) but I can not find any information regarding a reverse connection.
7
votes
1answer
126 views

What percentage of the human genome hasn't been sequenced yet? If percentage estimates aren't precise, why is it difficult to estimate?

What percentage of the human genome hasn't been sequenced yet? I have read different estimates, e.g.: https://www.genome.gov/human-genome-project/Completion-FAQ (mirror): "In the April 2003 version, ...
1
vote
0answers
34 views

What causes tenocytes to migrate from intact regions of tendon into the wound site, and how do they move?

The 2018 study {1} mentions that: The healing process of injured tendons includes tenocyte migration which occurs from intact regions of tendon into the wound site. What causes tenocytes to ...
3
votes
1answer
67 views

What differentiates neurons in different parts of the brain?

For example: what makes a neuron in the hippocampus of the brain different from a neuron in, say, the amygdala, or the frontal lobe, or anywhere else in the brain? Do neurons in different parts of the ...
-2
votes
1answer
51 views

Heritable immunity and smallpox vaccination [duplicate]

As I understand it, lack of heritable immunity caused smallpox to wipe out certain communities of native Americans. If vaccination conveys heritable immunity to a population, shouldn’t this make ...
1
vote
0answers
19 views

How does the structure of tendons change as they become stronger?

I understand the basic structure of tendons, but I wonder how a tendon becomes stronger via exercise. Do the collagen fibers become more aligned/numerous/dense/etc.? Is the tendon expected to become ...
1
vote
0answers
61 views

Why does it take 24 hours for tendons to give feedback on whether the loads they received were excessive?

I heard in this interview of Jill Cook (tendon researcher) on https://youtu.be/GKkSp-TlofI?t=230: Tendons talk to you 24 hours later. So what happens if if I put load on a tendon today, it will ...
29
votes
3answers
9k views

Can humans ever directly see a few photons at a time? Can a human see a single photon?

I am not asking the following question: Can humans ever see a photon in the same way we see a chair? My question is: Can a human retina respond to a single photon? If so, how does this happen and why ...
3
votes
1answer
153 views

Explain to a layperson how cigarettes smoke might cause cancer

I have a very intelligent friend who is a light smoker, and also a Biology layperson. I wondered whether understanding exactly how cigarettes smoke can cause cancer, might encourage him to smoke less ...
1
vote
0answers
49 views

What causes a tendinopathy to calcify?

I read in this 2012 research paper {1}: The aetiopathogenesis of CT [calcific tendinopathy] is still controversial, but seems to be the result of an active cell-mediated process and a localized ...
1
vote
1answer
58 views

How important is getting enough glucose for maximal brain performance / cognition?

I know from many studies that have been done, that resting versus active use of the brain has relatively similar overall energy expenditure levels. On the other hand, however, we know that the brain ...
1
vote
1answer
102 views

How can space travel affect women’s fertility?

From Time: The reasoning behind the prerequisite, according to officials, is that spaceflight could potentially harm the women's fertility. How can space travel affect a woman’s fertility?
2
votes
1answer
110 views

How do painkillers prevent shock?

I was reading about the Placebo effect and came across this little story: The roots of the placebo problem can be traced to a lie told by an Army nurse during World War II as Allied forces ...
2
votes
0answers
40 views

How does the strength of 3D printed tendons compare to original tendons?

There have been some attempts such as {1,2} to 3D-bioprint tendons. How does the strength of 3D-bioprinted tendons compare to original tendons? I am mostly interested in human tendons. References: {...
2
votes
1answer
71 views

Does loss of dopaminergic neurons totally eliminate voluntary muscular control?

Breathing is a function that is not only autonomic, but can also be temporarily overridden and placed under voluntary control. In fact, you are now breathing manually. Now, suppose that someone has ...

1
3 4
5
6 7
48