Biology pertaining to humans.

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1answer
230 views

Glycolysis and Non-Glucose Sugars

In my biology book's section on disaccharide metabolism and glycolysis, it states that sugars other than glucose must be acted upon to enter glycolysis. Let's take sucrose as an example. Sucrose is ...
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1answer
68 views

What are the effects of muscle and fat mass on survivability?

If we have humans A, B and C who are different: A is thin (skinny) without significant muscle or fat mass. B is muscular C is fat Which one of them has the best body for survival in accidents like ...
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0answers
58 views

Harmful effects of radiation from cell phone towers? [closed]

As per this article - http://www.thehindu.com/news/national/mumbai-citizens-link-cancer-to-cell-phone-towers/article5139166.ece , people living adjacent to cell phone towers claim to have developed ...
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1answer
217 views

Why does shaving dehydrate the skin? Is there an hormonal effect involved?

I want to understand why the face becomes dry after shaving and if shaving affects hormones? I've heard that after shaving, hair grows back faster, why? Shaving damages hair follicles and they become ...
4
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1answer
790 views

Which human cells have the longest and shortest lifespan?

Which cells in a human have the longest lifespan? Which cell has the shortest lifespan?
2
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1answer
167 views

How many consecutive cell divisions are required to form the adult human body from the single cell zygote?

The preferred question would have been what is the total number of cells in a full term human foetus and how many cell divisions are required to reach that number. However estimates of total cell ...
6
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2answers
557 views

What did we learn with Nazi human experimentation?

Was there actually any useful knowledge gained from the Nazi experiments on human test subjects? Wikipedia cites freezing and phosphine gas reactions, but I would like to know other potential results ...
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1answer
82 views

Calcium for Humans: Supplements vs Fortified Sources

I am intolerant to meat and milk products, but purely natural foods don't contain enough calcium for the Recommended Daily Intake. Links 2 to 4 (but NOT 1) avouch a correlation between calcium ...
2
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1answer
48 views

How correlated are proximally related CpG sites in human DNA?

Cytosine residues in DNA that can be methylated (i.e. CpG sites) are likely to be in the same methylation state if they are geographically (proximally) close together. I can only find one paper that ...
3
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1answer
54 views

What's the mechanism for pain-induced swoon?

Is it true that people will pass out when subject to pain too much to bear, or there's no such threshold? What's the reason for passing out under acute pain, even if no physical injuries occur (e.g, ...
2
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1answer
103 views

Are human feces and urine merely a subset of the food and liquid we eat and drink?

In other words, does the body actually ADD ANYTHING TO urine or feces? As the food and drink makes its way from our mouth to our toilets, does the body add anything to it along the way? Or, is the ...
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1answer
44 views

How precise is EEG?

Imagine we want to read impulses within single neurons in the brain. Can we do that now for a single region within the brain? If not, what is the smallest region that can be monitored for an activity ...
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1answer
59 views

What stops the coagulation process?

Whenever there are minor/major injury to blood vessels, the platelets, fibrin, thrombin, etc. are recruited. They then seal the wound and block bleeding. What tells them that their job is done?
2
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1answer
83 views

Other than Acetylcarnitine what other orally-bioavailable Acetyl donors exist to assist in the conversion of CoA to acetyl-CoA?

I asked a question on bio stackexchange a few days from which I was hoping to be able to arrive at an answer for this question myself but I have had no such luck so now I am going to just ask ...
5
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4answers
800 views

Why we have no enzyme to digest cellulose?

As we know, cellulose is the most abundant polysaccharide in nature. Why don't we have any enzyme to digest cellulose?
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0answers
32 views

How is oral cancer development and turnover rate of oral epithelium related

How is oral cancer development and turnover rate of oral epithelium related? Does their inverse relationship have genetic evidence?
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0answers
53 views

Are simple esters like those used as flavouring agents metabolised into their constituent carboxylic acids and alcohols in the human body?

By this I mean to ask whether say ethyl butanoate is hydrolysed in humans into ethanol and butyric (butanoic) acid. This is of interest to me as a pharmacology researcher because butyric acid, for ...
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1answer
109 views

Eating rarely but a lot, or often but little

I wonder if it matters if an average person eats the same amount of food distributed between a few (2-3) meals during the day, or constantly having small snacks. I'm interested in several aspects of ...
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0answers
37 views

Why do fresh cavities form from the margins of sliver amalgam fillings on teeth?

Silver amalgam fillings predominantly contain silver a known bactericidal agent and mercury which a known toxin and has bactericidal property. So how is it that the plaque bacteria survive near the ...
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4answers
120 views

Are biological systems engineered? They are often reverse engineered at a molecular level!!

Understanding biological systems, molecular biologists need to “reverse engineer” them. Is this evidence that the systems were engineered to begin with?
4
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1answer
269 views

What is a “mechanistic study”?

I believe a "mechanistic study" means a study where a medicinal product is being used but the purpose of the study is to investigate the patient or disease, not the medicinal product. How does this ...
2
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0answers
82 views

What tests can be performed to test the purity and quality of the raw peptide HCG (Human Chorionic Gonadotropin)

What tests could be run to test the purity and type of HCG? We are looking to purchase HCG from China but the purity and quality varies between labs, we are able to receive samples of the raw peptide ...
3
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2answers
101 views

Why do our eyes “wrap” hue from UV to IR?

On the high-wavelength side of things, we see almost-infrared as reddish, with a slight tinge of magenta. On the low side, we see violet fading into the same magenta color. Why is that? You can see ...
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0answers
22 views

What is an explanation of the dual role of calcium hydroxide in teeth?

Calcium hydroxide induces dentine formation in permanent teeth, while it causes resorption of tooth in deciduous teeth. How is this dual role explained?
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2answers
51 views

Can we identify an individual from their palm lines

Can we identify an individual from their palm lines. Is there any uniqueness for palm lines among family members ?
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0answers
23 views

Is there a difference in the amygdala in female homosapiens?

I read somewhere that claimed females initiate flight defends more than males, who tend to initiate fight more, that is it is claimed males will attack more than females when frightened. I believe ...
2
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2answers
72 views

Can the colour of skin change with age

Can the colour of skin change with age? Can a dark skinned person become fair or vice versa? Can Melanocyte production vary?
2
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1answer
45 views

The difference between “Hunger” and “Appetite”

When I am "hungry", I need something to eat physically. But what about "appetite"? I think it is a psychological phenomenon. Is that correct?
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2answers
67 views

Why does the mixture of infant formula with saliva provide an ideal breeding ground for disease-causing micro-organisms?

From: http://www.nal.usda.gov/wicworks/Topics/FG/Chapter4_InfantFormulaFeeding.pdf Discard any infant formula remaining after a feeding. The mixture of infant formula with saliva provides an ideal ...
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1answer
146 views

Why is the liver the only internal organ of the human body to regrow?

Related to my earlier question, "How does the human liver regrow?", am curious as to why the liver is the only major organ that has this capability? Why is it that other major organs, such as the ...
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1answer
49 views

When was the purpose of bone marrow discovered?

I'm currently reading William Cheselden's book Osteographia or The Anatomy of the Bones, which was published in 1733 (for the pretty pictures, naturally; not up to date anatomy). When he addresses the ...
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1answer
160 views

Why are human eye colours limited?

Related to the question What causes the colors we see in eyes?, I am wondering why human eyes are restricted in colour. Most common eye colours are blue, green and brown. Why not yellow, orange, ...
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1answer
28 views

Is it possible to suffer from hyperthermia by spending too much of time in the hot springs?

People may tend to spend time in a hot water spring. Is it possible to get hyperthermia (like a sun stroke) due to this?
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1answer
35 views

Axial skeletal system

I was curious about a fact given in my biology textbook as to why the Japanese have 3 pairs o floating ribs unlike the rest who have just two?
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2answers
931 views

Is there any use of CO2 in human body?

We all know CO2 as a waste product of metabolism . Does CO2 have any helpful role , apart from having a role in pH of blood ?
2
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1answer
213 views

Human body power consumption in still state

I'd like to know what kind of power human body needs to maintain life, in still state (average daily power consumption of an average man is also of interest). In terms of watts. I've only managed to ...
8
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1answer
58 views

What does the evidence suggest about how Neanderthals became extinct?

According to "Neanderthals: Facts About Our Extinct Human Relatives" (Szalay, 2013), Neanderthals dominated Europe during the last Ice Age, but may have died out before the arrival of Homo Sapiens ...
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1answer
176 views

Can food swallowed when a person is upside down reach the stomach?

If a person positions himself upside down and swallows food, will it reach the stomach against gravity? If so how?
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3answers
530 views

Why does it hurt when you take sweets, if you have cavities in your teeth?

When you have cavities in your teeth taking any sweetend drinks or food causes sensitivity or pain. What could be the reason?
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0answers
35 views

Can someone provide resources on human electromagnetic frequencies?

Pardon all of my questions below. I'm basically looking to find online resources regarding my inquiry. If you can answer any of them off the bat, that would be awesome!! It seems that humans and ...
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1answer
105 views

Characteristics of life

If all of the characteristics of life are required for something to be defined as living, how can we account people or other life that can not reproduce?
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3answers
159 views

How come that we “feel” it when someone's watching us [closed]

The question is relatively easy (the answer however..). We all know this feeling "being watched" and more often than not this is a real thing. If someone is staring at us from the side or from the ...
1
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1answer
447 views

Are there more/less favourable phases of menstrual cycle to donate blood?

I was wondering whether it makes a difference when during the menstrual cycle a female is donating blood in terms of: Blood quality (iron or hormones levels) Her health/safety I am aware that ...
2
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2answers
304 views

What is the best color for a PPG signal (photoplethysmography)?

What is the best color for a PPG signal? Red, green, blue or infra-red? I'm asking because commercial oximeter sensors usually use a pair of red and infra-red LEDs. But recently, I've seen a lot of ...
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1answer
193 views

Why does air from the nasal cavity not go into the oesophagus?

When we ingest food, the epiglottis covers the trachea and the uvula covers the nasal passage. But what happens when we breathe? Why does the air go into our trachea and not the oesophagus?
6
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3answers
130 views

Why are diabetic people often overweight?

I was looking at diabetes the other day, and I noticed something strange. Lower amounts of lipase are a symptom of diabetes, as is overweightness. However, since lipase is the enzyme that breaks down ...
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1answer
211 views

Do hormones make men think of sex?

I remember hearing a saying that goes like "men think of sex every 7 minutes (or seconds?)". I take this saying to mean that men have sex related thoughts more often than women. I'm interested if ...
3
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1answer
3k views

What is the standard deviation of adult human heights within sexes?

The wikipedia article on human height reports mean height for many different countries by sex but it does not report standard deviations. What is the standard deviation of adult human heights within ...
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0answers
178 views

Why do people sleep with their eyes open?

It's a fact that some people sleep with their eyes open, but why does that happen? Is it normal behavior, not a symptom of any sort of disorder? Are there any (dis)advantages to sleeping with eyes ...
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2answers
417 views

Do animals get sick from eating dirty food or eating off the floor?

Humans have very strict tradition of hygiene, such as washing hands before eating, using utensils, and in general keeping as much distance between food and dirt as possible. At the same time, most ...