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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3
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1answer
19 views

Is cyanocobalamin toxic?

I see that cyanocobalamin is not naturally occurring, and is synthesized in vivo to methylcobalamin. As part of the synthetic pathway, cyanide is broken off. All opinions I can find are that this ...
1
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0answers
10 views

Energy transformations in chemiosmosis and ATP synthase

In terms of energy, how does chemiosmosis drive ATP synthase? How does electrical energy turn into mechanical energy and then into chemical energy? Would the movement of $H^+$ be considered passive ...
-3
votes
1answer
37 views

What is a new biotechnology issue? [on hold]

I'm looking for any new biotechnology issue related to Biochemistry, Metabolic processes, molecular Genetics, or other relevant fields. If anyone knows of an issue that has solid resources around I'd ...
1
vote
1answer
17 views

Are more molecules of ADP than inorganic phosphate returned to the light reaction in photosynthesis?

During the dark reaction, 9 molecules of ATP are consumed for every 3 carbon dioxide molecules, yet only 6 molecules of inorganic phosphate ultimately leave the cycle. Does that mean that there is a ...
4
votes
1answer
54 views

When is Water Produced During Photosynthesis?

The formula for photosynthesis is: $$6CO_2+12H_2O \rightarrow C_6H_{12}O_6+6O_2+6H_2O$$ I can count the carbons, the waters on the reactant side, the oxygens, and the glucose, but I cannot seem to ...
3
votes
1answer
29 views

How Does NADPH Reduce 1,3-BPG?

If NADPH returns to being NADP+, then that means one proton and two electrons have been incorporated into 1,3-BPG. If only one proton and one electron were attached to the carbon in 1,3-BPG (removing ...
2
votes
1answer
20 views

Why are 2 electrons transported from photosystem II at the same time?

I only know that electrons are captured by the primary electron acceptor and then go through the electron transport chain, ultimately ending up at photosystem I. But why do 2 leave photosystem II in ...
3
votes
1answer
41 views

Why do some proteins “use” a beta barrel structure instead of alpha helices in transmembrane space?

Most proteins are fixed in the membrane by alpha helices. But some use beta barrels. Wikipedia describes beta barrels as used for porins, preprotein translocases, and lipocalins. To me, a coiled coil ...
4
votes
2answers
118 views

Do acetyl-CoA, acetyl-CoA carboxylase and acetyl-glutamate carry any charge?

Do the following compounds have any charge? If not, then why? If yes, is there any database that would give me this information if the compound is negatively or positively charged? The compounds are ...
4
votes
1answer
45 views

Do non-enzyme catalysed reaction pathways exist?

Can their be a kind of chemical reaction pathway in a cell, that is catalyzed or regulated but NOT necessarily by enzymes? I could not find anything on Google. I have almost no background in biology, ...
-5
votes
1answer
34 views

Questions with respect to a link [on hold]

With respect to this compound: http://www.kegg.jp/dbget-bin/www_bget?C00062 1. Is this a protein? 2. Does this compound have a pH or a pKa value? 3. If it does have a pH value then where can I find ...
2
votes
1answer
30 views

What does it mean when a protein has a different excitation spectra than wildtype, but the same emission spectra?

We have a GFP mutant that displays a different excitation spectra with emission at 510nm than the WT. However, their emission profiles with excitation at 490nm are the same, and we do not observe the ...
3
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1answer
34 views

Applying kiwis on gelatin

Kiwis have the enzyme actinidain. This enzyme will break the peptide bonds from the gelatin. Making gelatin with raw kiwis will not work, because the peptide bonds in the gelatin will be broken down. ...
1
vote
1answer
29 views

What are the factors on which protein-protein interaction depend? [on hold]

Does protein-protein interaction only happens when one of them is basic and the other acidic? Do protein interactions also depend on the protein structure? Are there more factors?
1
vote
0answers
10 views

Does creatine-phosphate (CP) supplementation regenerate NADH?

I have the following facts: It is possible to convert ATP <-> creatine vice-versa. (ref - non scientific) CP supplementation protects against metabolic syndrome. ref1 ref2 Fructose digestion ...
3
votes
1answer
33 views

Photolysis of Water?

In chemistry, I studied the decomposition of water as being $2H_2O_{(l)} \rightarrow 2H_{2(g)} + O_{2(g)}$. However, when water is split, the equation is $2H_2O_{(l)} \rightarrow 4H^+ + 4e^- ...
4
votes
1answer
52 views

Fats as energy source

As we know that the preferred source of energy for our body (source) are carbohydrates but heart muscle is an exception and need some explanation for this exception, that why the preferred source of ...
-2
votes
0answers
35 views

Naturally making green hair. What chemicals to use? [migrated]

Is there any chemical that is biologically produced in humans, that when impregnated in hair follicles, produces green hair? If current keratin follicles cannot do that, pick another biochemical for ...
4
votes
0answers
37 views

SDS Laemmli Gel that did not solidify

In my lab class this week my partner and I were making a SDS-PAGE Laemmli Gel. We made the resolving gel solution which was made of 30% Acrylamide, DI water, 1.5 M Tris-HCL pH8.8, and 20% SDS. We ...
2
votes
1answer
134 views

Green Film Build up in Glass Water Bottle

So I have this Large Water Jug that I fill only water with. And this is the 2nd time there has been a layer of green film that builds up at the bottom of the bottle. I don't have any way of getting ...
1
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0answers
23 views

How is ATP involved in muscle contraction?

The sliding filament mechanism as explained by my text does not elaborate on how ATP is involved in the cross bridge binding and contraction process. How does muscle contraction utilize ATP? In my ...
0
votes
1answer
33 views

DIY storing family DNAs' samples for future uses (eg medical)

I have a question I could not get an understandable reply from Google and I am no expert in the matter, so my plead to you is if you could give me practical and relatively easy to follow advice. With ...
1
vote
1answer
29 views

Given an EC50 value, how do I reproduce the sigmoidal curve from which this was calculated?

All-trans retinoic acid (atRA) is a potent ligand for a nuclear receptor called retinoic acid receptor alpha (RARa). The concentration of atRA at which RARa is half maximal is 19nM. The dose-response ...
0
votes
1answer
29 views

ratio between heat transfer coefficient and thermal conductivity [closed]

Consider the Robin boundary condition for the diffusion/heat equation $\mathrm{u_t=a(t)u_{xx}+f(x,t)}$: $$\mathrm{-k(t)u_x(0,t)=h(t)u(0,t)}$$ or $$\mathrm{u_x(0,t)+\frac{h(t)}{k(t)}u(0,t)=0}$$ ...
6
votes
1answer
29 views

What Goes on in Photosystems at the Molecular/Atomic Level?

In light-harvesting complexes, how is the energy of a photon transferred from one pigment molecule to another? And in reaction-center complexes, how does the primary electron acceptor capture an ...
2
votes
1answer
35 views

How to define drug-resistant or -sensitive cell line when knowing the IC50 values?

I have got the IC50 data for a drug on different cell lines. How to define if the cell line is sensitive or resistant towards this drug? Could anyone tell me how to define this?
0
votes
1answer
17 views

Beta oxidation of saturated fats

In my text book there is an example of a 18 carbon long fat and it says that it can run 8 laps of oxidation. I don't understand why it doesn't run 9? 2 are removed each cycle? Thanks.
0
votes
0answers
25 views

Why doesn't the body optimize how many fatty acids it burns?

Ketone bodies are produced due to an excess of fatty acids being burned (accumulation of acetyl-CoA) so my question is: Why doesn't the body simply regulate how many fats it burns so it doesn't have ...
2
votes
1answer
29 views

How are ketone bodies used?

While searching for literature on ketone bodies, I can only seem to find how they are synthesized, but not how they are broken down. I'm looking for the series of events with enzyme names and ...
9
votes
1answer
272 views

Why gluconeogenesis?

It seems quite pointless to me. Why would I want to use energy to create a molecule that I can then use again for less energy? It seems only to serve as a complete waste of energy to me? Can someone ...
2
votes
1answer
26 views

NADH shuttles - Why cytosol?

Why is the malate-aspartate and the glycerol-3-phosphate shuttles located in the cytosol and intermembrane space? The krebs cycle happens in the matrix so why wouldn't they push electrons from the ...
2
votes
0answers
19 views

Cholesterol's role in lipid uptake

I'm studying the digestion of fats and I understand that our dietary fats mostly consist of triglycerides. We absorb the fats and eventually they end up in a muscle/adipose cell for storage (as ...
0
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0answers
18 views

Where does the oxygen and water produced from the decomposition of hydrogen peroxide by catalase enzyme go?

How are they disposed of by the body, or are they disposed of at all? Since our body needs water and oxygen anyway, I'm speculating that these "waste product" will be reused/recycled by the body in ...
5
votes
1answer
143 views

Where do amino acids get attached to tRNA and where is it synthesized?

Some very basic parts of transcription/translation seem to be left out in various literature. I can't find the answer to this anywhere: How exactly is tRNA synthesized? I realize that mRNA is ...
4
votes
1answer
98 views

Water soluble molecules

I believe I may have misunderstood water solubility this entire time. I assumed that water soluble meant that it would literally dissolve in water. It would break down into atoms. A sugar molecule ...
5
votes
1answer
92 views

Why does a “cascade” of events happen during signal transduction?

I've been watching some videos on signal transduction and it says that because there are enzymes being activated by the signal, then there is a "cascade" which happens afterwards...I don't understand ...
2
votes
2answers
41 views

What are the typical values of probabilities for nonspecific binding to an antibody?

I'm physicist by training, so please excuse me if I don't use the proper terminology. I think there is a way to make a sensor that detects if a single antibody has caught something from the flow. So ...
1
vote
1answer
21 views

Pasteurization and Bioavailability of Antioxidants in Beet Juice

What are the effects of pasteurization on the antioxidants found in beet juice ? Does the process render most of the beneficial nutrients (betaine) useless and make them unable for the body to process ...
1
vote
1answer
18 views

Ways to cause membrane damage to microalgae and yeast?

I am researching a way to monitor the membrane damage of cells. To do that I fist have to have reference points, namely, cells with damaged membranes. I am working with Dunalliela, Hematococcus (both ...
3
votes
2answers
33 views

RNA polymerase question

In this question we are examining a bacterial RNA polymerase that elongates at 20 codons per second. Question 1: How long will this RNA polymerase take to transcribe the Lac Z gene at 3510 base pairs? ...
3
votes
3answers
62 views

Any good website/book to understand protein folding and enzymes?

I'm looking for a good, understandable and simple explanation about protein folding, mechanisms and function, and their relationship with enzymes. I understand that the protein is a polypeptidic ...
4
votes
1answer
49 views

Membrane potential in gram negative bacteria

Does the membrane potential usually quoted for gram negative bacteria (e.g. E. coli) refer to the potential across both membranes? - If yes, then does the potential fall more over the inner or outer ...
3
votes
3answers
63 views

Can bioluminescence be used for cancer or tumor detection? [closed]

What diagnostic applications, if any, are there in using bioluminescence to detect cancer or tumors (in vivo)?
15
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2answers
2k views

Is it known how the first viruses formed?

The oldest known virus is known to have infected prehistoric insects 300 million years ago. A virus is basically a parasitic strand if DNA or RNA encapsulated in a protein coat. It enters cells by ...
2
votes
1answer
67 views

Amino acid compatibility

The (human) genetic code encodes 20 amino acids. They form a protein using peptide bonds. Each amino acid has a carboxyl group (COOH) and an amino group (NH2) that can potentially form a peptide bond. ...
2
votes
1answer
17 views

Does mung bean nuclease cleave a phosphate group when it's chewing off 5' or 3' ssDNA ends?

I'm looking to create blunt ends from sticky ends with mung bean nuclease for subsequent ligation. Does anyone know full mechanism by which mung bean nuclease will do this? In particular after the ...
2
votes
1answer
36 views

Edman method to identify peptides with Phenylisothiocyanate (PTH)

We all know that in this method the PTH reacts with the first amino acid (aa) from the N-terminal to the peptide and separates from it giving PTH-aa so that we can know the amino acids sequence in the ...
3
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1answer
53 views

Proteins in Milk, Oat , Eggs and Soy

I have read that there are proteins in oat which are similar to those in soy, milk and eggs. I know nothing about biochemistry, and I'm struggling to decipher the info i find.. the closest Ive got to ...
1
vote
1answer
23 views

Hydrogen peroxide decomposition and catalase uses [closed]

All google searches have simply returned more info on catalase. I'm looking for a catalyst that isn't found inside living organisms which can break down H2O2. Looking for any resources to look at, or ...
10
votes
2answers
267 views

What is the explanation for the smaller number of tRNA than codons?

Translation, or decoding, of the four-nucleotide language of DNA and mRNA into the 20–amino acid language of proteins requires tRNAs and enzymes called aminoacyl-tRNA synthetases. To ...