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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2answers
67 views

What is the meaning of the “d(…)2” notation when writing a DNA sequence?

When the sequence of a DNA oligo is written as d(CGCTAGCG)2 what is the meaning of the d(...)2? Why would it not simply be ...
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 ...
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0answers
18 views

Why are amides transported via xylem vessels?

There is a statement in my textbook, ' since amides contain more nitrogen than amino acids, they are transported to other parts of plants via xylem vessels ' I wanted to know why the book specifically ...
2
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1answer
48 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 ...
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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0answers
115 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?
3
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2answers
66 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 ...
9
votes
1answer
76 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 ...
2
votes
0answers
21 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 ...
1
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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 ...
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 ...
6
votes
3answers
150 views

Is it possible to derive the Michaelis-Menten equation under conditions where the product formation is reversible

Text books etc generally derive the Michaelis-Menten equation for the irreversible case i.e $$\ce{E + S <=> ES -> E +P}$$ I can't see how to do it for the reversible case i.e $$\ce{E + S ...
3
votes
1answer
22 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? ...
3
votes
1answer
92 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 ...
1
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1answer
16 views
8
votes
3answers
194 views

How does the body switch between aerobic and anaerobic respiration?

Lets take the case of a person doing heavy exercise. Aerobic respiration is taking place, but oxygen is about to be finished up. Glycolysis occurs, Krebs cycle finishes. Now NADH and FADH enter ...
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0answers
17 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 ?
3
votes
1answer
30 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 ...
4
votes
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: ...
1
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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 ...
1
vote
1answer
22 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
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.
4
votes
1answer
73 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 ...
2
votes
1answer
64 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 ...
1
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0answers
38 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
62 views

What is the lower temperature limit for ion channels function?

What is the cold-block temperature of ion channels? (not of nerves or axons)
4
votes
1answer
84 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 ...
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0answers
30 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
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0answers
17 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 ...
10
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2answers
136 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 ...
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 ...
4
votes
1answer
160 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 ...
0
votes
1answer
69 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 ...
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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?
2
votes
1answer
88 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+ ...
0
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0answers
24 views

Does the source of caffeine affect the biological impact?

I've recently decided to give up my morning coffee in lieu of a caffeine pill. Both are around 200mg (my Tim Horton's XL 4x4 was 240 mg of caffeine) of caffeine. We were talking about the various ...
0
votes
1answer
25 views

Concentration of a specific promoter in a cell?

I want to simulate transcription activation by a given transcription factor (TF) with known kinetics. The binding rate $k_{on}$ is given in $\mu M^{-1} s^{-1} $, describing a bimolecular reaction ...
3
votes
1answer
62 views

What do proton pump inhibitors do?

I know that sodium azide and 2,4-DNPH inhibit proton pumps. The azide is called an inhibitor and 2,4-DNP is called uncoupler. I want to know what's the difference between the mechanisms of action of ...
0
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0answers
44 views

Why do denatured proteins tend to be less soluble than the native protein?

Why do denatured proteins tend to be less soluble than the native protein? In terms of hydrophobic effects, could anyone explain this phenomenon for me?
0
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0answers
15 views

Energy efficiency of carbohydrate > fat conversion

How efficient is the human body in converting surplus carbohydrate into fat? E.g., if you have 100 calories' worth of carbohydrates at the start of the process, how many calories' worth of fat will ...
1
vote
1answer
39 views

amount of tRNA and its extra arm

How much of the total RNAs is tRNA? Some say 15% and some 20%. Those percentages came from my different teachers. Which is correct? And what are the functions of the extra arm (variable loop) of tRNA? ...
0
votes
1answer
35 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 ...
0
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0answers
17 views

Separate replication origin and terminus vs making them one and the same

The classical picture of bacterial reproduction has a replication origin on one side of the circular chromosome and a replication termination area on the opposite end. This essentially creates two ...
1
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0answers
39 views

Molecular Biology and Genetics [closed]

What's the best textbook and online courses to study Molecular biology and genetics for undergrad student?
3
votes
1answer
78 views

What came first? The DNA or the DNA polymerases?

I know this sounds a lot like chicken and egg question and while the latter has an answer, I am intrigued about the former. A modified form of the question would be, in the course of abiogenesis, ...
2
votes
0answers
22 views

Glucose to Glucose-6-phosphate [duplicate]

What does actually occur- ATP is hydrolysed and esterification between glucose and HPO4^2- (formed as a result of hydrolysis) take place to form Glucose-6-phosphate or nucleophilic attack of O- of ...
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 ...
2
votes
0answers
45 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 ...
6
votes
1answer
56 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 ...