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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19 views

Roles of creatine and bilirubin in foetus circulation

I think they are not inputs from maternal placenta. I think they are the results of foetus metabolism. However, I do not understand it how and where exactly. What are the roles of creatine and ...
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1answer
14 views

Why doesn't the avocado turn green when it is kept with its seed?

Why doesn't the avocado turn green when its kept with its seed? What does the seed release that slows down the oxidation process?
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1answer
39 views

What can cause the swelling in high protein diet of Whey proteins?

I am thinking what can cause the swelling of high protein diet of Whey proteins. Liver does breaks those proteins to branched chain amino acids (BCAA), which can cause this swelling. However, I am ...
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1answer
40 views

Missing 4$H_2O$s (per glucose) in Cellular Respiration… Where can they be?

I having trouble understanding the equation of the cellular respiration. The thing that bothers me is the number of $H_2O$ molecules. Generally, cellular respiration is written thus : $C_6H_{12}O_6 + ...
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1answer
24 views

Correlating B-lactamase expression to absorbance

When penicillin-resistant bacteria are grown in liquid culture media, B -lactamase is secreted into the medium. The supernatant of such a medium can be assayed for B- lactamase activity. Culture ...
4
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1answer
119 views

What exactly makes bananas go brown?

I know that often oxidation processes are mentioned when referring to the color change from yellow to brown in bananas (specifically: those that you get everywhere in supermarkets, with no seeds). ...
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0answers
50 views

What is the biochemical pathway of fluoride?

Fluoride is a common active ingredient in tooth paste to prevent dental caries. It is also added or removed from the water supply in some communities for the same reason, but in children only. My ...
4
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1answer
58 views

What is an irreversible reaction?

There are reactions with large Delta G negative values. Why these reactions are irreversible? As in: out of 10 steps of Glycolysis, 3 are irreversible steps. I need an explanation for why they are ...
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1answer
52 views

Can we use Acetyl Phosphate instead of Acetyl CoA in TCA?

I am thinking Citric Acid cycle and activation of the end parts of Acetyl and alfa-ketoglutarate. Let's consider only now Acetyl to make things simpler. I have tried to explain the thing by symmetry ...
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3answers
63 views

Where can I find an at least Semi-Comprehensive list of what biochemical reactions Acetyl-CoA participates in?

Acetyl-CoA has a number of biochemical roles in the body and I'm curious as to whether anybody knows where I can find at least a semi-comprehensive list (i.e. comprising all the major roles in the ...
4
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2answers
50 views

Why isn't the phosphoglycerate kinase reaction of the glycolysis pathway irreversible?

Step 7 of the glycolysis pathway is the conversion of 1,3-bisphosphoglycerate into 3-phosphoglycerate by the action of the enzyme phosphoglycerate kinase, resulting in the production of 2 ATP ...
6
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1answer
757 views

Why is fructose not glucose the main energy source of sperm?

The seminal fluid contains fructose as the main energy source for the sperm and not glucose. Why is fructose and not glucose the primary energy source for these sperm, since glucose is the ...
2
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1answer
83 views

Other than Acetylcarnitine what other orally-bioavailable Acetyl donors exist to assist in the conversion of CoA to acetyl-CoA?

I asked a question on bio stackexchange a few days from which I was hoping to be able to arrive at an answer for this question myself but I have had no such luck so now I am going to just ask ...
2
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2answers
49 views

Humidity for wood rotting

If I put a piece of wood in a humid environment (basically humid air), it will start to rot. Does the humidity influence the rotting speed, and if so, what is the relation between the rotting speed ...
2
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2answers
41 views

Can excessive carbonated drink consumption lead to elevated red blood cell levels?

I've recently had a blood test and the results displayed elevated levels of erythrocytes as well as hemoglobin. (As a result my hematocrit levels were also above average) At my workplace there is a ...
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1answer
25 views

Cells created using differently aligned proteins

I remember reading that scientist were making cells (I assume bacteria), that used differently oriented proteins to create a whole new class of life. Because apparently right and left aligned proteins ...
2
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1answer
33 views

Substitute 25mM dNTPs mix with 10mM dNTPs

I need to make a solution of multiple compounds, one of them is dNTPs. The recipe calls for 20 μl 25 mM dNTPs in a 1250 μL master mix. Unfortunately I do not have it available at that concentration, ...
3
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1answer
37 views

Significance of lipids in biological membranes…?

Membranes are specifically designed by lipids to maintain internal hydrophilic environment in narrow range.There are hydrophobic amino acids among naturally occurring 20 amino acids and as well as ...
3
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1answer
20 views

Function of heparin and dextran sulfate for removing proteins

From this article : The reaction was terminated and the histones, and most nonhistones, were removed by adding the nuclease-treated chromosomes to a solution containing dextran sulfate (2 ...
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1answer
42 views

Bilayer synthesis? [closed]

If we want to design a bilayer from Myristic acid (14 carbon fatty acid). The average bond length between C-C is 1.5 A. What will be average thickness of the membrane? Edited to include the OP ...
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1answer
21 views

Concentration of DNA by isopropanol

I have read that DNA can be concentrated by addition of isopropanol. What does "concentrated" mean? What does isopropanol do on a molecular level to concentrate DNA?
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2answers
49 views

What would be the reaction to the flesh?

If an acid, salt, and alcohol solution were formed into a gel, what would be the reaction if injected into flesh and what would be the effect on the skin say for rough and cracked feet, acne, newly ...
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2answers
37 views

Functioning of EDTA

I know that EDTA chelates metal ions. It weakens bacterial cell wall and inactivates the DNases. What is the reason why it can do so ? I guess it can inactivate DNases by altering the ...
2
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1answer
35 views

Structure of biological membranes?

Integral membrane proteins have functional asymmetry i.e. they have two different domains of proteins performing different functions. these proteins have Tyr and Trp amino acid residues at the ...
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0answers
18 views

In what forms do plants and animals excrete sulfur?

Sulfur is part of the amino acids cystein and methionin, plants take up sulfur in the form of $H_2S$. These organisms will also need a way to get rid of excess sulfur, how? In what compounds? Judging ...
0
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1answer
30 views

What are the physiological roles of Hydrogen sulfide?

I am thinking why hydrogen sulfide has its effects in the body. For instance, it is one Salmonella's virulence factor. I am not sure if such a balance equations holds ...
2
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1answer
21 views

Transport of mammalian insulin in vivo

What is the mechanism for transport of insulin in mammalian cells?
2
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1answer
30 views

Activity of glucokinase

From Solomon et al, 2013 ACC Synthetic biology and from this video : Here, there are 2 competing reactions for glucose - one with glk as enzyme and other with gdh as enzyme. In the graph, y axis ...
24
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3answers
10k views

Death because of distilled water consumption

One of my friends said that I would die if I drank distilled water (we were using it in a chemistry experiment) I gave it a go and surprisingly did not die. I did a bit of Googling and found this ...
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2answers
125 views

Converting unit/mg or unit/ml into ng/ml, or vice-versa

I am working with the enzyme Cu/Zn Superoxide (SOD1) and i am quantifying them in ng/ml. However, most past studies has SOD1 quantified in unit/mg or unit/ml, and i need to compare the SOD1 level of ...
3
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0answers
40 views

enzymes that stabilize DNA loops

As a follow-up of a previous question, I would like to know what enzymes or protein complexes have been used to manipulate DNA samples into stabilizing DNA loops. I have read that cohesin is one of ...
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2answers
43 views

Why only water in liquid form is essential to live?

My question is:- Only liquid water supports almost every living organism's metabolism, neither the vapour nor the condensed form of water does so. What is the chemical & the biological reason ...
4
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2answers
194 views

In biosynthesis of cysteine and methionine, where does the sulfur come from?

Methionine and Cysteine are the two amino acids containing sulfur. According to wikipedia, cysteine is built from methionine. However, the wikipedia also claims that methionine is synthesized from ...
2
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1answer
31 views

Quorum Sensing in Vibrio cholerae

This is a figure summarising the quorum sensing mechanism in Vibrio cholerae. In this video by Bonnie Bassler, she explains how quorum sensing can be targeted to control infections. At 15:09 she ...
5
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1answer
585 views

The real definition of carbohydrates

Carbohydrates are often defined as compounds with only C, H, and O and the H and usually the O atoms are in a 2:1 ratio. Exceptions like deoxyribose exist, but why is it recognized as a carbohydrate? ...
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20 views

Nearly Exhaustive List for Cholesterol Pathways

I have run across an interesting case that is similar to only two others I've encountered. What makes it interesting is the combination of undetectable (under normal testing conditions, can elaborate ...
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0answers
44 views

Are DNA molecular motors described by cellular automata rules?

While watching this Molecular Visualizations of DNA it struck me how much the motion resembles Conway's Game of Life. And not only visually; each molecule/atom is described by a finite set of ...
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1answer
51 views

Diffusion of FAD+

Why is NAD+ free to diffuse within the mitochondrion whereas FAD+ is not ? What biochemical properties cause this difference ?
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0answers
32 views

Ferredoxin synthesis pathways

I have been thinking about some alternative CO2 fixation pathways. As almost all of them include ferredoxin reduction I started to wonder where does the ferredoxin comes from. I could not find any of ...
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2answers
48 views

PAH gene mutation

Analysis of the DNA of the Phenylalanine hydroxylase (PAH) gene in a patient with phenylketonuria revealed a mutation in the protein coding region whose predicted effect would be to replace the amino ...
0
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2answers
34 views

Why is succinate dehydrogenase attached to the inner mitochondrial membrane?

Succinate dehydrogenase is attached to the inner mitochondrial membrane.All the other enzymes of the Krebs cycle are located in the matrix of mitochondria. What is the biochemical reason behind ...
3
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2answers
39 views

Why do humans circulate monosaccharides instead of disaccharides as in plants?

Plants transport food mostly in the form of disaccharides like sucrose but humans transport them in the form of a monosaccharide - glucose. What is the reason behind this ?
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2answers
30 views

Clarification on Hatch and slack pathway

The following is a minor clarification that I want to make, since it is rarely addressed directly in most of the texts I have gone through. In $C_4$ pathway, the chloroplasts are dimorphic, that ...
12
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3answers
499 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 ...
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0answers
30 views

Enzymes that can catalyze multiple reactions [closed]

If the lock and key model were true, only one enzyme would be able to catalyze a reaction. However, some enzymes can catalyze multiple reactions. What are some examples of enzymes that can catalyze ...
2
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1answer
62 views

Isopropanol precipitation of DNA - duration and magnitude of cold storage

DNA prep protocols often include a final precipitation step with alcohol, often isopropanol, where the DNA must be kept in the alcohol, at a low temperature such as -20C or -70C, often overnight. ...
0
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1answer
57 views

Pathway mediates nitroglycerin-induced relief from angina pectoris [closed]

what kind of Pathway mediates nitroglycerin-induced relief from angina pectoris,please provide some idea...
0
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0answers
16 views

How do you express and detect GLP-1 receptors?

I am currently working with a peptide which is an analogue for glp-1, but during invitro studies am not able to detect for the presence of GLP1- receptors. The cell line used is Min-6. How do I detect ...
1
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1answer
16 views

Correlating Ki values of pesticides to bacterial growth

Four pesticides P1 to P4 are reversible inhibitors of an enzyme E that is essential for the growth of a bacterium B. Their Ki values are given in the table below. Each of these four pesticides ...
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0answers
11 views

To understand synthesis of e-NOS and n-NOS with respect to Ca and calmodulin

I found this sentence in my notes interesting E-NOS and n-NOS are Ca, calmoduline dependant ferments. They are synthesized from in small conc as response to physiological signals which ...