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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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 ...
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What is the shortest mRNA the ribosome can read to produce a peptide?

This question came as a comment on a previous question regarding non-ribosomal peptide synthesis, and why Glutathione cannot be synthesized by the ribosome. In general, Glutathione has a "gamma" ...
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Why does depolarisation by high intracellular K+ trigger calcium channels opening?

I have learnt that in pancreatic beta cells, glucose being metabolised in the cell causes a high ATP level, which triggers ATP-dependent potassium channels to close. This means that potassium can't ...
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101 views

Non-ribosomal peptide synthesis: why Glutathione cannot be produced by the ribosome?

Case: I am writing a summary for a class in protein structure and function, and was asked to describe some different ways that peptides are synthesized (that does not involve the ribosome). I ...
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1answer
25 views

Why would a bacterial population show initial growth when it is in unfavorable growth conditions?

This figure shows the anaerobe E. faecalis grown in aerobic conditions, E. coli grown in restricted conditions that are not specified. Why do they show an increase in abundance initially? The black ...
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88 views

Anomalous base pairing of nucleotide tautomers

What tautomers base pair with what bases? I know that adenine pairs with thymine and guanine pairs with cytosine normally. My question is what does the imino form of adenine base pair with? Regular ...
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1answer
89 views

Is there an evolutionary advantage for coconut oils to be rich in saturated fats?

I know that coconut oil is composed of multiple saturated fatty acids, but is there a reason why this would have increased the fitness of the coconut plant?
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16 views

What exactly are polyphenols and what benefits do they provide to humans?

I say somewhere that they are antioxidants, but I was wondering if the two terms are synonymous or if that is just one of many things polyphenols can do.
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49 views

On which amino-acids residue is the SDS acting on?

I would like to know exactly what is the mechanisme of the SDS, and I would like to know on which amino-acids residue the SDS is acting on. Can you help me please ? Thank you in advance !
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31 views

Difference between the P4 and P5 subtypes of P-type ATPases in plants

In plants there are various kinds of P-type ATPases. What is difference between P4-ATPase and P5-ATPase?
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35 views

Is Roundup toxic?

Roundup, as we all know, is a herbicide that kills weeds. It does this by preventing the production of amino acids in plants. One of these amino acids is tyrosine. Tyrosine is a nonessential amino ...
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1answer
221 views

Why does NAD+ become reduced if it gains a hydrogen proton?

I've heard that $NAD^+$ gains a Hydrogen proton during glycolysis and the Krebs cycle and becomes reduced to $NADH$. However, isn't reduction when a molecule receives an electron? Maybe I've been ...
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167 views

What are 'acid stable' amino acids?

I tend to see terms amino acid, acid stable amino acid, and free amino acids used often in ...
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35 views

Which Lactobacillales (Lactic acid bacteria — LAB) strains are capable of degrading starch?

I've been researching bacteria strains but am having trouble finding amylolytic LAB strains with amylolytic and lactic acid producing character. The only species I've found, that are capable of ...
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1answer
29 views

kinetics question [closed]

An enzyme has a $V_{max}$ of 50 $\mu$mol product formed $(min * \text{mg protein})^{-1}$ and a $K_m$ of 10 $\mu$M for the substrate. When a reaction mixture contains the enzyme and a 5$\mu$M ...
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1answer
63 views

Bradford Reagent Disposal

I am a graduate student volunteering in a professor's lab being tasked with finding out how to dispose of certain hazardous materials. I have encountered a problem with disposing of Bradford's ...
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59 views

metabolism preference by the body

What I know about metabolism is that,during exercise body uses carbohydrate first then fats and then protein,so my question is why does body prefer glucose first as fuel for energy and what makes ...
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163 views

Is it possible to stop yourself from going into shock?

https://en.wikipedia.org/wiki/Shock_(circulatory) I was helping someone move a refrigerator down steps and it slipped while I was holding a sharp corner and it sliced my finger and there was ...
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1answer
38 views

Where does the inverse seconds unit come from in the association constant?

I'm working to determine Kd(s) kinetically by generating association and disassociation curves. Kon (association constant, or on-rate) is in inverse seconds multiplied by inverse molar. I get that ...
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33 views

What cures pineapple burns?

If you already ate too much bromelain in pineapple, how do you cure your tongue burn?
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25 views

Is there a good easy protocol for extracting proteins(enzymes) from fungal mycelium?

I quantify the enzyme (polygalacturanase)activity by DNSA method.To determine endo-polygalacturonase activity I'm searching for a good easy enzyme extracting method.Any suggestions for a suitable ...
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1answer
56 views

which organelle produce glycogen phosphorylase and why

I know that Glycogen phosphorylase doesn't produce from rough endoplasmic reticulum in liver cell. But almost every proteins such as insulin receptor, serum albumin, and lysosomal enzyme have to ...
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14 views

Growth of Yeast in Different pH Mediums

Will yeast grow better in acidic, basic or neutral mediums? Why? Will the medium affect the growth of yeast? (Yeast cell membrane is semi-permeable).
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50 views

What are the differences between carnitine forms?

I've heard of L-carnitine, acetyl L-carnitine and L-carnitine L-tartrate. What form(s) occur in meat? What form does the human body manufacture? Is L-carnitine just a shortened name for L-carnitine ...
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1answer
72 views

What do the numbers in Photosystem I P700 and Photosystem II P680 stand for? Is it the optimum wavelenght? The maximum wavelenght?

I am a bit confused about this because my teacher and english Wikipedia say it's the wavelenght the Photosystem is most reactive to; my textbook and the german Wikipedia say that it is the maximum ...
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23 views

Question about Collagen and Glycosylation

Just curious, I know that collagen typically undergoes O type glycosylation. However, can you say that this type of glycosylation is essentially like putting a mailing address for proteins to be ...
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1answer
108 views

Why does SDS-PAGE use for protein, and agarose use for nucleic acid?

My question maybe very primary, but after I learned this part, questions always follow me. SDS-PAGE gel works for detect protein, agarose gel works for detect nucleic acid, so here is my question: 1. ...
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93 views

Membrane Permeability to Pyruvate

Pyruvate seems to pass easily through the outer membrane of the mitochondrion but has difficulty entering the inner membrane (and gets in by H+ symport). I have two questions: (1) what property of ...
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180 views

How to find the concentration of an enzyme?

I need to know the concentration of pectinase enzyme (sigma aldrich) which has stated 5KU, 5U/mg protein (lowry) and lot result 20U/mg protein in the label of the enzyme bottle. This is all it has ...
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1answer
40 views

Making positive charged polyacrylamide

I am interested in positive charged polyacrylamide to electrophorese molecules I am interested in. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2643323/ ...
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34 views

Birth control hormones in the water? Or not?

This prior question talks about natural estrogen (TL;DR: Months to years): How quickly do estrogens break down in the environment? Ref: http://dx.doi.org/10.1038/485441a A lot of media has said, ...
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3answers
584 views

Do we consume dna, proteins of other organisms?

When we eat raw meat, e.g. chicken or fish, we are actually consuming the DNA, proteins etc. which are present in their cells. Wouldn't this affect our cell functions as this DNA might enter our ...
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1answer
150 views

Why is it often the case that an enzyme is favorable only towards one direction of a reaction and not both directions?

In class when we're studying enzymes like amylase or protease it only works well when you're using it to break down compounds like polysaccharides. I'm just curious but why is it not possible for ...
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1answer
78 views

What is a detailed chemical explanation for describing how an enzyme may lower the activation energy of a reaction?

If you can provide some sound reasoning that touches on tertiary structures of proteins and does not use a lot of advanced chemistry jargon that might be really helpful, especially for an intro ...
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48 views

Fibronectin glass surface adsorption

Short summary I'm having a glass surfaces and I want to adsorb proteins onto them. I have no problem, when I first adsorb fibronectin (human) onto some areas and afterwards any other protein. The ...
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1answer
89 views

What is a mechanical cue?

I was attending a talk related to neurogenesis. So one professor was asking a question related to biochemical cues and mechanical cues (related to signaling pathways I believe). Cue as far as I ...
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31 views

Soy kefir that never revitalises in animal milk

If I have kefir grains from goat and I make soy kefir and never revitalise the kefir grains in an animal milk, will that bacteria still be beneficial for the gut? What type of bacteria does it make? ...
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1answer
90 views

How will changing the concentration of a Tris buffer affect amylase enzyme activity?

For instance if you increase the amount of Tris but pH still does not change then will the enzyme activity still proceed normally? If it does change the pH will it change enzyme structure and why?
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1answer
81 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 ...
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68 views

Root etiology of non-pituitary low T4 and low TSH

Please note: I'd like to preface this question by stating that this is neither homework nor me seeking medical advice. I am simply trying to understand the biological, physiological root etiology ...
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28 views

Consumption of different type of energy when one is inactive

I'm wonder if there is any study done on this and what are the results? how much of each type of energy one's body(healthy normal person) uses when inactive(seating down) I know there are alot of ...
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1answer
109 views

Why do the deoxyribonucleotides use T and ribonucleotides use U? [duplicate]

We all know deoxyribonucleotides form DNA while ribonucleotides form RNA, DNA is double stranded while RNA is single stranded, and RNA can transcribe from DNA. We also know that DNA use A, G, C, T, ...
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41 views

Properties that can be derived from amino acid sequences [closed]

What are the properties that can be derived from an amino acid sequence apart from those mentioned in the website? In the mentioned website, the properties that can be calculated from amino acid ...
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2answers
165 views

Equilibrium and Metabolism: Can cells exist at STATIC equilibrium? What about dynamic equilibrium?

I understand that in closed systems, once reactions reach equilibrium, they can no longer be used to power other reactions. If a cell was a closed system (which it is not), being at equilibrium would ...
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1answer
109 views

Are all dipeptides synthesizable?

Probably a basic question, but are all possible dipeptides synthesizable? For 20 amino acids, there should be in principle 190 dipeptides; do they all exist or is there chemistry that makes some ...
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1answer
37 views

Is galvinoxyl antioxidant assay possible using NMR spectroscopy?

I would like to perform an antioxidant assay using the galvinoxyl protocol. The protocol states that we need EPR spectroscopy, but only NMR spectroscopy is available at my institution. Is there an ...
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2answers
89 views

Extending a small fragment of DNA

Is there a way to extend a small fragment of DNA, say 150 bp, by making copies of itself and attaching each copy of that small fragment to the end of that 150 bp sequence? For example, I want a ...
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3answers
202 views

Why does all life use the same macromolecules in their genetic code?

There is no biochemical constraint of any sort, so why doesn't some other code work? Why is it specifically RNA/DNA?
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1answer
81 views

What happens when we eat excess fat?

The fats in our body are stored in fat cells. When we over eat fats does the size of our fat cells increase, are more fat cells generated, or do we "throw out" excess fat?
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How to read this diagram?

I have diagram of oxidative decarboxylation of pyruvate pathway. The pathway is between glycolisis and Krebs cycle. How to read this diagram? This excerpt from Harper's Illustrated Biochemistry, ...