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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6
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1answer
47 views

Is there a difference in cytoplasmic pH between prokaryotes and eukaryotes?

The cytosolic pH in human cells is around 7.4, but fluctuates as the cell is replicating. Prokaryotes and eukaryotes are vastly different in many ways. One thing they share is cytoplasm. Is there any ...
9
votes
1answer
86 views

Why do animals have more heavy nitrogen and carbon than plants?

There are two stable Isotopes of nitrogen N14 and N15. The ratio of 15N/14N tends to increase with trophic level, such that herbivores have higher nitrogen isotope values than plants, and ...
34
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6answers
3k views

Why are there no organisms with metal body parts, like weapons, bones, and armour? (Or are there?)

Reading this question, Why are there no wheeled animals?, I wondered why no organisms seem to make use of the tensile and other strengths of metal, as we do in metal tools and constructions. I am ...
6
votes
1answer
40 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) ...
2
votes
1answer
50 views

Why does protein kinase C activated by different means have different effects?

I could be way off base but I think I remember learning that Protein Kinase C has some effects when activated by one pathway and other effects when activated by another. How does this happen? Is it ...
0
votes
1answer
36 views

Energy input during ATP Dephosphorylation?

What is the energy input needed to break the phosphor bond during ATP Dephosphorylation? How and when this will occur? Many thanks for your answers. Edit 1: I know how much free energy (∆G) is ...
1
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0answers
23 views

If chylomicrons can not get into the capillaries, how do they supply to tissues?

The transport of chylomicrons is into the lacteals mainly because they are too big to get into the capillaries and yet they later supply triglycerides in the extra hepatic tissue by traversing in the ...
1
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1answer
31 views

How is the enzyme glycogen synthase regulated?

How is the enzyme glycogen synthase regulated in regards to glycogen synthesis? I think I understand that phosphorylation decreases its activity (through glycogen synthase kinase?), but what role do ...
3
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0answers
117 views

Whole gene sequence analysis to determine source infection [closed]

Is it possible to use whole gene sequence analysis to distinguish between a common source infection and a person-person disease transmission?
1
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0answers
24 views

Can aptamers be used to identify the terminal amino acid residue of a peptide?

Suppose there were DNA or RNA aptamers that bind specifically to a certain terminal amino acid residue. Let's name it aaSA (amino acid specific aptamer). For example, the aptamer binding to terminal ...
3
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2answers
69 views

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 ...
3
votes
2answers
134 views

How do muscle cells synthesize glycogen?

Hexokinase enzyme is present in all cells (including muscle cells) and can be suppressed by excessive G-6-P product. So that's why in the liver, glucokinase can act on glucose without inhibition of it ...
2
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0answers
26 views

What is the function of CETP?

I read up that CETP transfers cholesterol from HDL, which collected it from tissues, to VLDL. This VLDL is then sent back to the tissues, ultimately forming LDL internalised by cells. What is the ...
2
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0answers
28 views

What is the rationale behind reverse cholesterol transport?

Reverse cholesterol transport is transport of cholesterol from the tissues back to liver/VLDL. My question is why do the tissues have this extra cholesterol in the first place? Why would you ...
5
votes
1answer
65 views

Is it possible to isolate and analyse intermediates of protein folding?

I would like to know if there is an assay which could allow us to analyse a protein before it has assumed its 3D functional form. While studying structural biology, I only came to know the forces that ...
4
votes
0answers
54 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
44 views

Lookup for transporter locations in humans

I am interested in several transporters and cotransporters (eg SLC12A1/2 and many others), more precicely, in (human) organism that are made of cells containing those transporters. So does anyone know ...
3
votes
3answers
302 views

Is there a known glucosepane cross-link breaker?

I read the following on wikipedia: There is, however, no agent known that can break down the most common AGE, glucosepane, which appears 10 to 1,000 times more common in human tissue than any ...
3
votes
1answer
94 views

Why is competitive inhibition reversible?

My Biochemistry book mentions that 'competitive inhibition' is a reversible form of inhibition. But given that the inhibitor is blocking the active site and prevents an enzyme-substrate complex to be ...
2
votes
1answer
71 views

Are alpha-ketoglutarate and glutamate involved in all transamination reactions?

Is it true that for all biochemical transamination reactions, that alpha-ketoglutarate and glutamate serve as the amino group acceptor and donor, respectively? If this is true, then is it safe to ...
2
votes
0answers
51 views

Real Wine and Real Bread Superfoods? [closed]

On NPR news on the Fm Radio a doctor said wine and bread is the best 2 things you can eat together? A practice observed to this day by Christianity although the bread and wine are badly stripped of ...
3
votes
1answer
66 views

How does heat generated by metabolism differ compared with heat generated through exercise?

I am from a mathematical background so I don't have much knowledge on biology. I'm building a mathematical model to predict heat generation with parameters of metabolic heat generation and exercise ...
2
votes
1answer
30 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 ...
3
votes
1answer
24 views

How can dopamine modulate synaptic strength?

Does dopamine act on G protein coupled receptor, leading to more Ca2+ channels on the postsynaptic knob? Also, how is the specificity of the location (of the brain) that dopamine acts on controlled? ...
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?
1
vote
1answer
40 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 ...
1
vote
1answer
35 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?
10
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2answers
143 views

Protein tertiary Structure formation

As we know that coils and loops are evolutionary variable regions where mutations,deletions, and insertions frequently occur. So does it mean that they don't have much role in the structure of ...
4
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0answers
29 views

Derivation of Michaelis' Equation from Michaelis' Constants [duplicate]

The enzyme reaction condition, $E + S \leftrightarrow ES \rightarrow E + P$ uses $\kappa_{1}$ (forward reaction), $\kappa_{-1}$ and $\kappa_{2}$ as the rate constants. E: Enzyme S: Substrate P: ...
5
votes
2answers
419 views

How is respiration an unbalanced equation

The equation for respiration is C6H12O6+6O2→6CO2+6H2O+36ATP. The chemical formula for ATP is C10H16N5O13P3. How is this possible, since it violates the law of conservation of mass because it is ...
3
votes
1answer
33 views

How to transform snail shells into a fertilizer? [closed]

I heard that the chemical structure of the snail shell has elements that help in waste water treatment and in some cases as a fertilizer? What is the process used to render snail shells into ...
1
vote
0answers
19 views

How does the snail shells' fertilizer compare to regular fertilizers?

May I ask about the quality of the fertilizer derived from the shells and their effectiveness compared to other fertilizers on the market ?
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3answers
40 views

Statistically, why is the number of mutated genes in eggs treated with chemical mutagenesis one?

Excerpted from the Guide to Research Techniques in Neuroscience [1]: In chemical mutagenesis, a scientist applies a mutagenizing chemical, such as ethyl methane sulfonate (EMS) or ...
4
votes
1answer
170 views

Why is ab initio protein secondary structure prediction less reliable than alternatives?

To predict secondary structure of proteins three types of Algorithms are used Ab initio, homology based and neural networks. Among these neural networks prove to be more accurate and give good results ...
1
vote
1answer
23 views

What are in common between transcription factors?

In terms of their structures (primary to tertiary) and locations? Why do they have these commonalities? Or are any of these commonalities critical to their functions?
4
votes
1answer
87 views

What is the significance to life of the anomalous properties of water? [closed]

I have heard that the anomalous properties of water - e.g the fact its solid form is less dense than its liquid form - is extremely important. In fact, some people have gone so far as to tell me it ...
3
votes
1answer
63 views
4
votes
1answer
86 views

What is the process of degradation of proteins into amino acids inside living cells?

Just like beta oxidation does our cells have a distinct mechanism for degradation of proteins? There are processes for degradation of amino acids but where does these amino acids come from, is it all ...
4
votes
2answers
147 views

Do desulfhydrase-catalysed reactions take place in animal cells?

It isn't a homework question. I'm just stuck with desulfhydrase reactions and am unable to find enough information in the usual places. Any external source on this topic would be helpful.
1
vote
0answers
39 views

Are cold-blooded animals more energy efficient than warm-blooded animals? [duplicate]

When cold-blooded animals extract energy from glucose, do they do so in a more efficient manner than warm-blooded animals? If they aren't producing heat as a by-product, that would suggest that ...
3
votes
1answer
77 views

Prediction of transmembrane beta barrels?

I studied that prediction of transmembrane alpha helices is more easy and accurate and also good algorithms are available for their prediction. But when we move towards prediction of transmembrane ...
1
vote
2answers
84 views

Getting PCR amplification at annealing higher than Tm!

I am amplifying a gene where in a gradient pcr i am getting amplification at an annealing temperature about 5 degrees (67) higher than Tm (62.5)? What is wrong here? Also, I am getting a very strong ...
1
vote
0answers
32 views

Question about DNP derivatives of amino acids (specifically epsilon-DNP-lysine)

I have a pretty basic biochemistry question but am having trouble finding the answer to it: Normally, 1-Fluoro-2,4-dinitrobenzene (DNFB) reacts with just the amino terminus of amino acids. However, ...
0
votes
1answer
70 views

How are 6 “fixed” CO2 molecules joined toegther as glucose?

When we study calvin cycle, we study it with 6 molecules so as to form 1 glucose in a single cycle as: 6 RuBP + 6 CO2 => 12 3-PGAL => 1 Glucose + 6 RuMP But if we look deep, then we know that the ...
0
votes
0answers
19 views

How to promote denitrifying microbe activity

I'm an amateur fresh-water aquarist looking at the problem of nitrate reduction (into largely-inert nitrogen gas) in a small-scale aquarium environment. The process of turning the byproducts of fish ...
0
votes
1answer
60 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 ...
7
votes
2answers
8k views

Molecularly, why can you straighten or perm hair?

I'm aware that hair can be curly because of the disulfide bond interactions in between cysteine amino acids in alpha-keratin filaments. However, I'm curious as to the biochemistry involved in ...
4
votes
1answer
92 views

Why it seems that principles of chemistry are not being applied in this biochemical process? [closed]

According to an answer in this question, my concept used below does not apply: In the non-cyclic photophosphorylation, consider splitting of two water molecules, then 4 e- (electrons) and 4 H+ ...
1
vote
0answers
11 views

Function of NEZHA gene [closed]

What is the function of NEZHA? What effect does it have on microtubules and PLEKHA7? What happens after it has been knocked down?