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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2
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1answer
33 views

Advantage of GCPRs over RTKs or other receptor protein kinases

My book lists two important differences between GCPRs and receptor protein kinases: GCPRs do not directly activate a signal transduction pathway. It only does so indirectly, via a G protein. On the ...
2
votes
0answers
87 views

Convert flux value in nmol/min/mg protein to nmol/min/cell?

This is a question about unit conversion. I found an experimental measurement of the saturation uptake of glucose in yeast: $$V_\textrm{max} \approx 650 \textrm{nmol}/\textrm{min}/\textrm{mg protein}$...
6
votes
1answer
138 views

How do disulphide bonds in hair cause curling?

I understand that the asymmetrical distribution of disulphide bonds in hair cause curling, but do not completely understand why this causes an inherent curl on the macroscopic level, for several ...
4
votes
1answer
127 views

All-or-nothing-law: law or general principle?

The all-or-nothing principle indicates that a nerve cell fires at maximum potential or not at all, based on a threshold on the stimulus. Is this a statement which is always true, or only mostly-...
4
votes
0answers
56 views

How do animals with fur get enough sunlight to produce vitamin-D? [duplicate]

How is vitamin D synthesized in animals with fur; how do the cells get enough sunlight? If vitamin-D cannot be synthesized because of limited sunlight reaching the skin, do these animals have to ...
1
vote
1answer
260 views

Difference between negative allosteric regulation and non-competitive inhibition

Both connect to some site other than the active site which controls the shape of the active site and causes the enzyme to be less active. So what is the difference?
1
vote
1answer
41 views

How does cytochrome c oxidase inhibition cause cell death?

I realise the inhibition of cytochrome c oxidase prevents the release of H+ ions into the intermembrane space, and that the ion gradient is required for ATP synthase action. However, I'm not sure how ...
0
votes
2answers
23 views

Can an enzyme be activated without allosteric inhibition or activation?

Are there ways by which an enzyme may be activated or inhibited by non substrate molecules other than allosteric activation or inhibition?
1
vote
1answer
36 views

BWA-MEM single strand or doublestrand alignment

In whole genome secondary analysis does BWA-MEM use a double stranded fasta reference or are reads aligned to only one, single stranded fasta reference?
3
votes
1answer
150 views

Why does Citric Acid occur in Citrus fruits?

Why is there so much citric acid in citrus fruits? And how did it evolve i.e. what did it come from? Is it a by-product of the ripening process? Why have citrus fruit evolved a particularly high ...
6
votes
1answer
44 views

Why aren't plants and animals capable of assimilating $\ce{N2}$ directly from the atmosphere?

From a E-book written by Hungary scientists, the reason is $\ce{N2}$ is inert. Is this correct? How does the chemical properties of gas species ($\ce{SO2}$, $\ce{O2}$, $\ce{NH3}$, etc) ...
4
votes
1answer
81 views

What causes the opaque green colour in Lepidoptera?

Link here to what I mean by 'opaque' colouration on the insect, the colour intensity remains constant despite changes in light intensity and angle (not shown by the picture but the moth exhibits this ...
0
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0answers
24 views

Determination of Ageing by ECG inclusions/exclusions?

I am studying ageing and considering ECG signal because of its high sensitivity in theory (escardio). Some factors Sensitivity Gender Medical treatment ... Benchmark: RTG dental + wrist ...
1
vote
0answers
16 views

Panel 9 urine/ prescribed ADDERRALL XR [closed]

My doctor conducted a Genesight test, finding out that I am an ultra rapid metabolized. Often times, my body will metabolize my medications before they enter my system. Thus is why my prescriptions, ...
0
votes
0answers
147 views

How do CAM plants keep stomata closed by day and open at night?

I understand how plants open stomata, with the H+ ion removal and the resulting K+ ion influx in the guard cells to induce turgor (wikipedia article here), though not how this process relates to ...
4
votes
1answer
1k views

How does a Plasmodium move?

Plasmodium sp. does not have any locomotory organs. So, how does it move? What biochemical process allows it to move?
4
votes
1answer
48 views

Why is metabolism of ethanol catabolism? Could it be also detoxification?

Detoxification is the physiological or medicinal removal of toxic substances from a living organism, including the human body, which is mainly carried out by the liver. Additionally, it can refer to ...
0
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0answers
8 views

Is there a deblocking aminopeptidase without normal aminopeptidase activity?

The deblocking aminopeptidase is a unique exo-type aminopeptidase that liberates blocking groups (formyl, acetyl, and myristyl) from proteins and peptides. However, according to this paper, it has two ...
0
votes
1answer
29 views

How are the two ATPs (properly 1.5 though) formed from oxidation of 1 FADH2?

Each ATP Synthase has three sites for binding three sets of ADP and Pi, so when the H+ pass through the a and c subunits are they (3 ATPs) not produced for FADH2 substrate? Besides is the ...
3
votes
1answer
153 views

How many protons are pumped out per pair of electrons from NADH in oxidative phosphorylation?

I have searched the web and found that 10 protons are suppose to get pumped out during the electron cycle, but i'm a bit confused. I'm trying to count, for every complex(1/3/4), the number of protons ...
1
vote
1answer
51 views

What is meant by electron transfer potential?

I was reading a text and came across the term. What does it mean? The sentence said 'The driving force of oxidative phosphorylation is the electron transfer potential of NADH or FADH2 relative to that ...
1
vote
0answers
27 views

Is it possible to separate the binding and catalysis of an enzyme in two steps?

Is it possible to do the following: Enzyme E binds to its substrate S without catalysis; Add a controllable stimulus, such as light, adding or removing chemicals; The enzymatic reaction is triggered ...
1
vote
0answers
34 views

What are other creatures or plants that leave “recommendations” as ants? [closed]

I'm working on a Semantic Recommendation Systems. In the state-of-the-art, I state the fact that even animals, such as ants, using some kind of recommendations by leaving markers, which are chemical ...
1
vote
1answer
62 views

How difficult is it to make a shRNA/miRNA/siRNA to silence/knockdown NaV1.7 voltage gated sodium channels in humans?

There have been various research projects that experimented with shRNA/miRNA/siRNA to specifically silence/knockdown NaV1.7 voltage gated sodium channels in small animals like rats & guinea pigs. (...
4
votes
1answer
52 views

Is HSV-vector-mediated miRNA expression in dorsal root ganglia stable?

My question is on the following article: "Reduction of voltage gated sodium channel protein in DRG by vector mediated miRNA reduces pain in rats with painful diabetic neuropathy" My question is, do ...
6
votes
2answers
307 views

At any given moment, how much energy is stored in the human body as ATP?

At any given moment, approximately how much energy is stored in the human body as ATP in the ADP-P-bond? This of course depends on what type of cell it is and the activity of the individual in ...
1
vote
0answers
34 views

Assays to determine competitive binding versus non-competitive

I'm looking for both simple and complex assays or technologies than can be used to determine if two competing molecules are competitive or noncompetitive. I figure xray crystallography is a clear one,...
7
votes
2answers
290 views

How many ATP are formed?

What is the number of ATP molecules formed during the photosynthetic processes which consume 8 molecules of $\text{H}_2\text{O}$ due to noncyclic electron transport and subsequent photophosphorylation?...
0
votes
1answer
69 views

Why do raw prawns turn red after sitting in vinegar?

Yesterday morning I put some raw prawns (shell removed) into vinegar (more specific this one), and put them in fridge. When I came back at night all of them turned red, which looks cooked, except ...
1
vote
1answer
110 views

Where is sialic group in gangliosides that form ABO blood groups?

A ganglioside is a molecule composed of a glycosphingolipid (ceramide and oligosaccharide) with one or more sialic acids (e.g. n-acetylneuraminic acid, NANA) linked on the sugar chain. (source: https:/...
1
vote
1answer
89 views

Is a fat-soluble vitamin a lipid?

I read in a chemistry book that a steroid is a class of lipids, and that the fat-soluble vitamins like vitamin D are part of steroids. So is a fat-soluble vitamin a lipid? This makes me confused as ...
1
vote
0answers
25 views

How do microbes develop resistance to anitmicrobial peptides?

I would like to better understand how bacteria use the "strategy" of alternations to lipid A and membrane proteins in order to resist antimicrobial peptides of the immune system? It is my ...
3
votes
1answer
80 views

Do we actually know the molecular dynamics of any enzyme?

That is right, is there a limitation, say Heisenberg's uncertainty principle or something that limits our understanding of machinery of enzymes at atomic level? Can we know how do they actually work? ...
2
votes
1answer
42 views

Differences among competent cells?

What are the differences among the following competent cells DH5 alpha, Nove blue, and BL21? Why some of them are for cloning and others are for protein expression? Any references where I could find ...
1
vote
1answer
122 views

How the chaotropic agents help in purification of DNA molecule?

Those plants which are rich in secondary metabolites and polysaccharides DNA isolation can be done using certain chaotropic agents? can any one explain how it works?
0
votes
0answers
27 views

What do the cholinergic system and protein kinase A pathways have to do with inflammation?

In the middle of a comprehensive review of all experimental research to date related to my graduation topic, I have run into a little bump in terms of how these pathways affect inflammation, and how ...
5
votes
1answer
145 views

What would happen if Carbon-14 was in a glucose molecule and decayed into Nitrogen?

This interested me because of Melvin Calvin's experiment with photosynthesis where he used radioactive Carbon-14. If a plant used it as a reactant to make glucose, and that Carbon-14 decayed into ...
0
votes
0answers
22 views

About electrons returning to photosystem I when supply of NADP runs out in photosynthesis

According to my textbook, in photosynthesis, when the supply of NADP runs out, electrons from photosystem I return to the electron transport chain that links the 2 photosystems and flow back to ...
7
votes
1answer
87 views

About acetyl-coA in the Krebs Cycle of respiration

In respiration, Krebs cycle starts with acetyl coenzyme A which is made from pyruvate. However, it is said that the cycle keeps repeat it self with oxaloacetate turning back to citrate and cycle ...
4
votes
2answers
338 views

Why are human titin and mice titin considered the same protein?

I have a book that says: In humans titin is a chain of 34,350 amino acids, but in mice it is even longer with 35,213 amino acids. If two polypeptides had different amino acid sequence lengths, ...
1
vote
1answer
77 views

Why are nucleic acids negatively charged at physiological pH? [closed]

Why do nucleic acids and mononucleotides have a negative charge physiological ph?
0
votes
0answers
33 views

Where can I find the pathway for cAMP signaling in Dictyostelium?

I wanted the cyclic-AMP signaling pathway network of social amoeba Dictyostelium discoideum (which is necessary for the understanding of its "aggregation" life cycle) with rate constants and other ...
2
votes
1answer
69 views

What is membrane-partitioning free energy? Can it be simulated?

Firstly, is there a strict definition of the "membrane-partitioning free energy"? It is banded around in membrane biology, but I have never seen it strictly defined. The only non-scholarly site that ...
3
votes
1answer
109 views

Why is photosynthesis so complex?

Actually, what is the need of such long procedure? As much as I have understood, the sole purpose of photosynthesis is to synthesize carbohydrates, which is only used for energy storage. So, why don't ...
3
votes
1answer
126 views

The effects of auto-brewery syndrome

Why are some people affected so differently by auto-brewery syndrome differently if the syndrome seems to be caused by the single organism saccharomyces cerevisiae? It is known that the syndrome has ...
0
votes
1answer
46 views

Why does vitamin D need to be exogenous?

Vitamin D is a either a hormone or a precursor to hormones. It is very unlike any other vitamins, which are either cofactors or antioxidants, or may be other chemicals necessarily performing catalytic ...
2
votes
1answer
177 views

Is honey in hot green tea unsafe?

I used Google to try to figure out what kind of mixture honey has with hot water, and I found several Ayurvedic sources claiming that honey in hot water is toxic. For example: Honey – NEVER Put It ...
1
vote
1answer
43 views

Stabilizing forces between the protein sequences?

we know that Protein structures from secondary to Quaternary are maintained by noncovalent or weak interactions including electrostatic interactions,van der Waals forces & hydrogen bonding. What ...
3
votes
0answers
62 views

What is the advantage of using plant-derived antibacterials rather than bacteria-derived antibacterials?

So obviously we have a big problem with antibiotic resistance. Most of our antibiotics originate from bacteria themselves (or are synthetic variations on scaffolds which originate from bacteria). I ...
2
votes
1answer
843 views

Difference between protein channels, protein carriers and protein pumps?

I'm revising for my biology exam and I don't fully comprehend the difference between protein channels, carriers and pumps. I know that: Protein channels do not require ATP (passive transport) The ...