9 votes

Can We Determine the Cell Types Ab initio?

No. Cell types are identified by differential gene expression. Every cell has (effectively) the same genome, but different expression patterns give you different functions. You could attempt to ...
Bryan Krause's user avatar
  • 45.3k
9 votes
Accepted

If race doesn’t exits; why do humans look so different?

Definitions of race as we normally use it varies greatly from culture to culture, ones based on actual Biology don't match our preconceived ideas. You could break humans into races, but if you do ...
John's user avatar
  • 14.6k
7 votes
Accepted

Potential Function of Knuckle Popping?

Is the function of the popping of knuckle to retard the hand slowly, hence reducing the force when hit? No. The only physiological effect of popping the knuckles is to temporarily stretch the joint ...
anongoodnurse's user avatar
4 votes

Would the human body somehow get rid of very fine glass particle(s) that have penetrated the skin?

If we assume that a single particle has penetrated the skin on your finger, possibly beneath the epidermis layer (meaning it can't be shed through the normal skin shedding process), are there any ...
anongoodnurse's user avatar
4 votes
Accepted

Why does hyperventilation make you feel like you need to breathe more?

Hyperventilation alone does not cause you to feel that you're not getting enough oxygen. Rather, it's what causes hyperventilation that does that (thus resulting in hyperventilation.) The Calm Clinic ...
anongoodnurse's user avatar
3 votes
Accepted

Are there any "good" gases which "accidentally" diffuse into the lungs and get exhaled?

Biological scientists do not usually ascribe moral attributes to metabolites, despite the use of the term ‘good’ in reference to lipids by those who communicate with the public. So I think it better ...
David's user avatar
  • 25.2k
3 votes
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Can citrate in semen be utilized as a source of energy by the sperm?

Many microbes can use citrate as a carbon source for catabolism or anabolism. Citrate however is not a dominant (if at all) energy source for human cells because transport of citrate across the cell ...
fairy_bluebirb's user avatar
3 votes
Accepted

What is the difference between digesting sugar and carbohydrates?

Scope of Answer The original poster provided ample context for his question, which related to health considerations. It was perhaps for this reason, among others, that the question had not received an ...
David's user avatar
  • 25.2k
2 votes
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Can humans metabolize D-malate?

I do not have specific proof, but I strongly suspect that the answer to this question is NO on the basis of the following arguments. The overwhelming majority of sugars, amino acids, carboxylic acids ...
David's user avatar
  • 25.2k
2 votes

Can the effect of an allele on height be context-dependent?

Polygenic scores are very good at predicting height. This figure, from https://arxiv.org/pdf/2101.05870.pdf, predicts height using common SNPs at r = ~0.65. In a different study, "combined with ...
BigMistake's user avatar
2 votes
Accepted

What determines if a compound is primarily taken up by the lymphatic extensions rather than the portal vein blood supply in the intestinal villi?

The path used for a particular compound is determined by several factors: Affinity for Plasma Proteins: Compounds with a high affinity for plasma proteins are more likely to remain in the bloodstream ...
Robert Long's user avatar
2 votes

Question regarding statistical testing for fractions in low N paired samples

You don't have enough data for traditional statistical hypothesis testing. No statistical test will get you around this fact. I'd recommend just reporting the raw data when there are so few numbers. ...
Bryan Krause's user avatar
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2 votes
Accepted

Why is mean systemic filling pressure used to calculate pressure differential for venous return?

I think the words tripping you up are "mean" and "systemic". Specifically, it sounds like your intuition is that you should be thinking about an average (mean) across space, across ...
Bryan Krause's user avatar
  • 45.3k
2 votes
Accepted

How can saliva neutralise acids produced by bacterial cells in our mouth if it is itself acidic in nature?

Saliva is neutral, not acidic (6.8 is very barely acidic), and is a means to carry the acid away physically, and is also much less acidic than acid produced by bacteria, so is still effective in ...
BigMistake's user avatar
2 votes

How does $\ce{H2CO3}$ form in the blood with a ratio of 1:20 with $\ce{HCO3-}$ if there are not enough $\ce{H+}$ ions

Bicarbonate and its conjugate acid buffer the blood due to their intrinsic behavior (pKa/pKb) of donating $H^{+}$ if there is too few (high pH) or taking up $H^{+}$ if there is too much (low pH). You ...
KaPy3141's user avatar
  • 1,597
1 vote
Accepted

Is the 5% of the oxygen used in the breathing process fully transformed into CO2?

When you write the number "21%", it represents equally all numbers rounded to 21%; that is, 21% is the same number as 20.5% and 21.49% under the most common rounding convention. When you ...
Bryan Krause's user avatar
  • 45.3k
1 vote

What is health?

So the book invokes individuals with low levels of psychopathology and negative thought. They have very high scores in psychometric health tests. Yes most of us have average symptom levels of mental ...
bandybabboon's user avatar
  • 10.4k
1 vote

How does $\ce{H2CO3}$ form in the blood with a ratio of 1:20 with $\ce{HCO3-}$ if there are not enough $\ce{H+}$ ions

It has to do with the buffering activity of Hb and $\ce{HCO3-}$ leakage. $\ce{H2CO3}$ dissosiates inside the RBCs and the resulting protons, $\ce{H+},$ bind to Hb, decreasing proton pressure caused by ...
user7777777's user avatar
1 vote

Confused about the transport of materials across cell membranes

A few short inputs: The membrane is permeable for some molecules but not for others. Small and uncharged molecules can pass easily (such as H2O). Others like Sodium (Na+), Chloride (Cl-) etc. have a ...
Felix H.'s user avatar
  • 318
1 vote

What is the oxygen concentration in the lumen of the small intestine?

From a recent review by Konjar et al. (2021), see Figure 2 and associated text: There is also a steep decrease in oxygen longitudinally from the small intestine towards the colon. Longitudinally—...
S Pr's user avatar
  • 6,202
1 vote

Bacteria and semi-permeable membranes

A semipermeable membrane is like a sieve. It has pores on the surfaces and tunnels that connect them. Molecules may pass through depending on their size. The pores in semipermeable membranes may be ...
Mark Andrew's user avatar
1 vote

How does Bernoulli’s Principle apply to the cardiovascular system?

I love this question, and there is a number of things to unpack. Exactly where we are measuring a pressure in that circut matters. We usually measure a persons BP in the brachial artery, so relatvely ...
Ryan 's user avatar
  • 11

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