Questions tagged [biochemistry]

The study of chemistry within the scope of biology: the compounds that occur and the reactions involving them in living organisms.

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Is there a chemical reaction that blocks two cysteines by reacting with a third molecule?

The idea is to block the two cysteines so they can't react in the future. We need the reaction to remove the -SH groups of the two cysteines, or modify them. Also important, the reaction should not ...
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Why do beta-1 and beta-2 adrenergic receptors result in two completely different effects (though both use Gs pathway)?

$\beta_2$ adrenergic Receptors are $G_s$-coupled 7-TM proteins. Considering that $G_s$ , by activation increases $[\text{cAMP}]_\text{cytosol}$ which inhibits MLCK of smooth muscles (and causes ...
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Absorption of glucose in small intestine

During the absorption of glucose in the small intestine, glucose enters the epithelium by Na+/glucose co-transporter by the concentration gradient of Na+. The gradient is generated by pumping 3Na+ out ...
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Apparent paradox in Glucagon action

Glucagon stimulates glycogenolysis and gluconeogenesis, thus increasing plasma glucose concentration — so that tissues get enough glucose at fasting state. However glucagon also inhibits glycolysis. ...
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Coronavirus: Why does soap inactivate the virus on skin, but not on surfaces?

In a comment on "Stability of SARS-CoV-2 in different environmental conditions", published today in The Lancet Microbe, it is stated that household soap is highly effective on the skin. Not ...
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Why is Ibuprofen contraindicated in asthma patients?

So yesterday a patient showed up at the clinic with a massive swelling in his left face region. Upon examination it was found to be due to infected first premolar. Dentist recommended him to get the ...
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Why severely increased Ligand (eg Hormones) concentration downregulates the Receptor?

As an example continuous high blood level of GnRH in humans causes a suppression of LH and FSH. This is due to the fact that increased GnRH downregulates GnRH-Receptors . My question is how this is ...
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What is the difference among these compounds?

I'll preface this question by making clear that I'm not not well versed in biology. Anyway, within the context of biocides/antimicrobial products using them as active substances, what is the ...
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Some Biological processes are erroneously named due to their order of discovery.Why can't these be corrected to match their role?

While reviewing the biochemical processes which make photosynthesis possible, and the photon capture by chloroplast machinery in plane cells the initial step you come across is Light in form of ...
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kcat in uncompetitive enzyme inhibition

Why doesn't $k_\text{cat}$ change in uncompetitive inhibition, given the fact that uncompetitive inhibition lowers the enzyme–substrate complex efficiency (which is the reason for lowering of $V_\text{...
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Why does the sandalwood tree produce a fragrant oil?

Why do sandal trees produce fragrant oil? Is there any purpose for it? Is it to make it unpalatable for other herbivorous animals? If so, why do humans find the fragrance pleasing?
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How are logarithmic trendline equations used to determine antibody concentrations in ELISA?

For example, say you have plotted a standard curve and managed to obtain a logarithimic trendline equation like: y = mln(x) - b And you are working with data that includes: a) standards,their ...
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Partial pressures of different gas in human blood and how they are calculated?

In Respiratory Physiology, we use the $P_x{O_2}$ and $P_x{CO_2}$ in blood at different regions of the peripheral circulation. From my Chemistry knowledge I know that $P_x$ of a gas in a solution is ...
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On the science of DNA modifications putting animal genes into humans and modifying a human

I am wondering about the possibility of modifying DNA or changing DNA of a human being.... I am wondering if something like this can be possible in the future when DNA structure has been fully ...
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Do cats produce DMT?

Edit: If somebody (anybody) wants to add an answer so the bounty won't go to waste, please do so! The comments have already introduced me to the Kegg metabolism database, some interesting papers, and ...
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Book recommendation: protocols and recipes handbook for molecular biology / biochemistry

I'm a 5th-year PhD student in chemical biology. I've mostly been doing computational work, so my bench skills are rusty. To help me, I'd like a handbook of common techniques -- transformations, ELISA, ...
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Activated carrier molecules and their relationship to enzymes

I am reading Molecular Biology of the Cell, and one thing I don't quite get is the difference between an enzyme and an activated carrier molecule. I understand that enzymes lower the activation energy ...
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Why do insects' “most sensitive photoreceptors” consume so much energy that it exerts evolutionary pressure to minimize their number?

The video Wireless Steerable Vision for Live Insects and Insect-scale Robots from the University of Washington's Paul G. Allen School of Computer Science begins with the following: Vision is an ...
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What would cause a single white eyelash?

I couldn't find a paper who could give me the explanation. Unfortunately, according to my search, it seems there are not many reported case, particularly for the younger population (<30). Would ...
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Can bacteria metabolize fatty acids for fuel?

I'm not a microbiologist, but rather a physiologist curious about microbial metabolism. Much like humans bacteria can utilize glucose, but when it comes to long chain, medium chain, or short chain ...
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Why doesn't enzyme reaction rate rise linearly with substrate concentration?

This is the graph of the Michaelis-Menten equation which describes the relationship between reaction rate and substrate concentration: I don't understand why it is hyperbolic. Intuitively, I would ...
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Enzyme kinetics at the chemical level

I am stumped by two questions: Why do we take only the initial 10%(or may be 9.99999....%) of S conversion as the rate of the enzyme reaction. why not more than 10%? Why doesn't the velocity keep on ...
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What is the half-life of dNTPs at 95⁰C?

I'm looking for the half-life of dNTPs, either as a whole or broken into individual bases, at 95 degrees C (or similar). A titration would be great if that exists. I can provide more specifics if need ...
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Why does the HPV vaccine not work on already infected people?

With my limited knowledge, I understand that the vaccine works by inserting fake HPV-like material in the body, thus inducing the immune system to build up defenses against it, so when the body is ...
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What is the biochemistry of love?

How is love induced between humans? Say, between mother and child, couples, etc. Does the phenomenon of love exist in other mammals, too?
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What is the ultimate source of ADP/ATP in humans?

I am teaching myself Cell Biology from the internet. Despite my usually good Googling skills, I'm stuck in a loop with this question. Q: What is the source of ATP? A: ADP Q: What is the source of ...
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Why is it (allegedly) dangerous to feed ducks with breadcrumbs and pieces of bread?

I used to go down to the local lake all the time with leftover bread and throw little pieces of it to the hungry duckies, who very eagerly fetched it and ate it while happily quacking away. I thought ...
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How do anticholinesterase pesticides kill nematodes?

Compounds that inhibit the enzyme acetylcholinesterase are commonly used as pesticides. In animals with centralized respiratory systems controlled by the nervous system, poisoning with an ...
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1answer
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State of extracted DNA

A well-known and commonly-done experiment is to extract DNA from strawberries or other fruit by first mashing the fruit of choice, adding the mush to a mixture of water, salt, and detergent, and then ...
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What are the differences between how latewood and earlywood forms and how does this effect it's properties?

In trees the earlywood forms a somewhat abrupt transitions to the darker latewoods that happen during the summer months. What are the chemical differences that arise in this wood at the cellular and ...
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Is there an antidote for caffeine, e.g. as a supplicant for caffeine-intolerant persons?

First, let me state I'm not talking about a medical emergency. No one is in a serious condition. My girlfriend is, we think, caffeine-intolerant. She loves the smell of coffee and the habit of coffee ...
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Quantification of various amino acids from bacteria?

I would like to characterise how much of various (uncommon) cytosolic amino acids are produced in bacteria, and was wondering if there are good suggestions of how to go about doing this. I know that ...
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educational sources for learning biochemistry

I just finished high school and am going into a biology undergraduate degree, I'm getting into biochemistry too and would like to learn more about it through online platforms or even non-fiction books ...
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How does SDS-PAGE separate based on mass?

In SDS-PAGE, electric field and mass-to-charge ratio are approximated to be constant for all proteins. Also, if $F=qE =ma$, then $\frac{m}{q}a=E$. Thus, all proteins must migrate with a constant ...
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Why does hair turn grey or white, and why does it happen later for some?

The question is pretty simple: what is happening molecularly when hair turns grey or white? I would imagine that it is due to the lack of a particular compound. I'm also interested in why some people'...
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What is the charge on oligonucleotide 5' pGpGpApCpT 3' at pH 7.00? [closed]

What is the charge on the nucleotide 5'pGpGpApCpT 3' @ pH 7.00? I thought adenine has 1 NH group and Guanine has NH and ...
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Biochemistry of production of a yogurt counterpart from coconut milk

About yogurt: The biochemistry of changing animal milk to yogurt is well known. Recapitulating: After some preperatory steps the milk is inoculated with bacteria that consume lactose, producing lactic ...
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What does it mean to be a fully human monoclonal antibody?

I somewhat understand that some monoclonal antibodies are developed from the cells of mice, or a fusion of human and mice genes. When something is a fully human monoclonal antibody does that mean it ...
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Will ammonia continue to accumulate in an aquarium tank if a strong antibacterial or chlorine is added to the water?

I've always wondered what would happen if dead plants and fecal matter lay in chlorinated waters and/or waters treated with strong antibacterials or antibiotics. I've heard that aquarium tanks ...
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If Melatonin is anti-gonadal, why is it associated with early sexual maturity in congenitally blind girls?

If melatonin is anti-gonadal, that is, it delays sexual maturity, then shouldn’t it delay sexual maturity in congenitally blind girls rather than helping them attain sexual maturity at an early age?
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Meaning of units in ELISA based tests?

For some ELISA based antibody tests (e.g. h-tTg antibody test), labs report units as RU/mL or U/mL. Also different labs have different cut off (normal range) values. I understand that different kit ...
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Human Digestion of Cellulose?

Most animals can digest the cellulose in grass because of the anaerobic bacteria called Fibrobacter succinogenes living in their rumen (gut). The bacteria produces the enzyme cellulase and is ...
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Cellulose structure

In cellulose structure, some beta glucose are inverted. I’ve read that therefore the hydroxyl groups stick on both sides, but aren’t there hydroxyl groups on both sides anyways whether it was inverted ...
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Can catecholamines degrade back into tyrosine, or, is synthesis irreversible? (in human body)

Catecholamines like dopamine, noradrenaline and adrenaline are broken down with enzymes that catalyze the reaction. Can they degrade back into tyrosine (a conditionally essential amino acid), or is ...
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Reverse oxidative phosphorylation?

I noticed that all of the cellular energy production methods that I covered have a fixed ratio of ATP to NAD(P)H out. For example, in the combined process of glycolysis, pyruvate oxidization, and the ...
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VPg priming of the replication of RNA viruses

I'm doing a presentation on the replication of SARS-CoV-2 for my chemistry class, and I found that to replicate its RNA, the virus uses RNA-dependent RNA polymerase, which is primed by a VPg primer. ...
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Vitamin A Deficiency

I have a quick question regarding Vitamin A deficiency. The photoreceptor molecules in both rods and cones have the same general structure which is retinal which is bound to a protein called opsin ...
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Testing the viscosity of honey?

I am carrying an experiment where I will be measuring the viscosity of honey using Zahn cup but I don't know what is the optimal and efficient size and the size of the opening to purchase if you can ...
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Reasons why this protein is not suitable as an immunogen?

In a paper entitled "Progress and Prospects on Vaccine Development against SARS-CoV-2", the authors write the following in section 2.5: "Compared with S, N, and M protein, E protein is not suitable ...
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CO2 availability to phytoplankton in oceans and climate change impacts

I learned through research that increasing levels of atmospheric CO2 was increasing the acidity level of ocean waters. I then was looking into how this was affecting the phytoplankton and read that ...

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