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Questions tagged [biochemistry]

This tag is for questions concerning biochemical methods (e.g. electrophoresis) or those concerning biochemical mechanisms or research. Do not use this tag if your question is merely about compounds often used in areas related to biochemistry or associated with these. These may fall under organic chemistry or the appropriate compound’s functional groups’ tags.

Questions that are related to any living organism should have this tag. However, chemicals that are needed in life, e.g. proteins, enzymes, etc. can also have this tag, provided that the question being asked is concerned with how these proteins, enzymes, etc. affect living organisms.

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Why isn't aluminium involved in biological processes?

There are so many biological processes which are dependent upon ions of lighter metals (upper part of periodic table) such as $\ce{K+}$, $\ce{Na+}$, $\ce{Mg^{2+}}$ and even early transition elements ($\ce{Fe}$, $\ce{Mn}$, $\ce{Cu}$, $\ce{Ni}$), but…
animul
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Why does menthol (e.g. peppermint) feel cool to the tongue?

Especially when drinking water after the fact, mint can give a sharp cold sensation inside one's mouth. What process causes the sensation to occur?
Daniel
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What are the border definitions in the Ramachandran plot?

I've heard some people mention that this or that program isn't "up to date" with respect to the borders used in the Ramachandran plots to classify φ/ψ as being in the most favorable/acceptable/disallowed regions. How are the accepted regions…
Nick T
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How does dimethyl sulfoxide transport other molecules through skin?

Wikipedia says: Use of DMSO in medicine dates from around 1963, when an Oregon Health & Science University Medical School team, headed by Stanley Jacob, discovered it could penetrate the skin and other membranes without damaging them and could…
daf
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Why Lysine is abbreviated as 'K'?

It does not has a 'K' in its name. It does not have a potassium in its chemical composition. Would be nice to know why Glutamine is Q too, some of these abbreviation seems simply random.
Andrew Au
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Diffusion and potential gradients for two similar atoms

Studying biochemistry I noticed that equilibrium is reached for K and Na separately (not taking into account electric potential), as would be the case I assume for any molecule or atom. This is of course entropy. Eg: My understanding is, you have…
user4779
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Why is iron used in the body?

I'm writing a report on the spectrophotometric determination of iron. In my introduction I want to briefly explain the importance of iron in the human body. Wikipedia states that "Iron is essential to life due to its unusual flexibility to serve as…
Jack
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Does this cycle of reactions appear in nature?

Does anyone know a real-world example of a cycle exactly like this: or in other words, this: $$\begin{array}{ccc} \ce{A + C1 -> C2}\\ \ce{X + C2 -> C3}\\ \ce{C3 -> B + C4}\\ \ce{C4 -> Y + C1}\\ \end{array} $$ where the reaction $\ce{A -> B}$ is…
John Baez
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What makes a good antioxidant?

I am doing a school project on antioxidants and I would like to find out what makes a good antioxidant. I know examples of antioxidants such as Vitamin A, C and E but I was wondering what commonality exists between them in terms of chemical…
John Doe
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Why is arsenic toxic to humans?

I don't understand why arsenic is toxic and why it does damage to humans. Could it be that it is so similar to phosphorous? If so, would that make antimony toxic as well?
Ile Senoj
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What is "stuffy"/"stale" air composed of?

When a room is not ventilated for a long time (days if people are present, weeks if not), humans perceive a change in air quality commonly described as "stale" or "stuffy" air. What is going on here chemically? How is "stale" air different from…
user44672326
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Fatty Acid synthesis - enzymes that vertebrates cannot make

In the fatty acid elongation and desaturation reactions, how are enzymes that insert double bonds after the 9th carbon different from those that insert at the 9th or before? Vertebrates (at least mammals) don't have these enzymes.
PB Vanc
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How is ATP generated by cellular respiration?

I learned in a high school level Biology class that the chemical equation for cellular respiration is $$\ce{6O2 + C6H12O6 -> 6CO2 + 6H2O + ATP}$$ When I looked up the chemical formula for ATP I found that it is $$\ce{C10H16N5O13P3}$$ Knowing…
Eliot
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What would make guanidinium ions and urea more effective denaturants of proteins in some cases, but not in others?

Some proteins do not unfold, or only partially unfold due to chaotropic agents such as guanidinium ions and urea. What are some reasons for this?
Chylomicron
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Why is cytosine far more vulnerable to hydrolytic deamination than both adenosine and guanosine?

Why is cytosine far more vulnerable to hydrolytic deamination than both adenosine and guanosine? Here's the source for the claim (the half-life is 340 years at 298 K, which is much smaller than that of adenosine and guanosine).
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