The function of chemistry within the scope of biology; the study of the compounds that occur, and the reactions involving them, in living organisms.
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87 views
What are the variables that control/influence the color of oranges(Citrus sinensis)?
I hear that Oranges cultivated in tropical areas of the world tend to be greener when ripe, is that correct?
Even the same type of Orange differs in color if cultivated in California or Florida. I ...
8
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2answers
261 views
Why do people say that trans fatty acids are bad for your health?
I've heard from several sources that trans FAs are bad for you and their consumption will lead to cardiac problems, and that they are indigestible.
But I also learned from biochemistry that they are ...
8
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1answer
557 views
Why is GTP gamma S non hydrolyzable?
GTP gamma S is routinely used in studies of G proteins to stably activate the G protein. Comparing the structures of GTP gamma S and GTP, the Sulphur atom replaces the Oxygen attached to the leaving ...
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2answers
150 views
Solution based measurement of Solvent-Accessible Surface Area of macromolecules
The Solvent-Accessible Surface Area (SASA) is a valuable metric for looking at protein folding and protein-protein interactions. However, this measurement is typically done by calculating the SASA ...
8
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1answer
121 views
What is the maximum potential sucrose concentration of plant sap? What keeps plants below this potential?
I am interested in identifying the maximum potential dissolved sucrose (%w/w) that plant sap could have, and which (biological, physical, chemical) factors constrain the observed sucrose ...
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3answers
162 views
What alternatives are there to the amyloid hypothesis?
Given the recent failure of the Bapi clinical trial, there is a lot of questions that have arised from he amyloid hypothesis. However, I can't really think of many other mechanisms that don't involved ...
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3answers
100 views
Free Radicals for aging
From my understanding free radicals play a slight role in ageing.
In what ways are they so damaging, and can a restricted diet reduce production of free radicals?
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2answers
148 views
How to compute properties of peptides ?
I have been tasked with writing a program for computing properties of a give set of peptides. These peptides are given as 1-letter amino acid sequences and I need to compute the following :
Length ...
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1answer
8k views
NADH vs. NADPH: Where is each one used and why that instead of the other?
I know NADH is used in cellular respiration and NADPH is used in photosynthesis. What difference does the phosphate group make that the same one isn't or can't be used for both? Is there a greater ...
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1answer
257 views
Does drinking coffee have negative effects?
From what I collected, coffee is a magical potion that lets you feel energetic, and essentially not-sleepy. But are there any tradeoffs? I mean, if it was so beneficial, wouldn't the human body ...
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1answer
132 views
What makes a wet dog so stinky?
Similarly, what makes a wet down comforter so stinky? Why do they make no smell except when liquid is added?
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1answer
1k views
Why does RNA adopt an A-form helix?
RNA is known to form an A-form helix, while DNA generally forms a B-form helix under physiological conditions.
From left to right: A-form DNA, B-form DNA, Z-form DNA. Image created by Richard ...
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2answers
158 views
Can a living organism run on electricity?
Each time I'm too lazy too cook I think it'd be cool to be able to just plug myselt into an outlet. Yet I know it is not possible - I need amino acids and a lot of other stuff that electricity can't ...
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2answers
141 views
Bacterial cell lysis - what solution to use?
I am trying to determine how quickly detergents act on bacterial cells (cell lysis). I would like to compare some detergents at difference concentrations for bacteriolytic activity. I don’t care about ...
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2answers
116 views
During famine, does the human body do anything to prioritize which organs receive nutrients?
When food is scarce, the body slows its metabolism. Are there any other systems or processes that encourage prioritization of organs?
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1answer
333 views
Single hormone opposite effects
Often, a smooth response to a hormone means that some processes must be sped up and others must be slowed down.
How can a single hormone have opposite effects like this?
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2answers
193 views
How can I measure bacterial alkaline phosphatase activity?
I want to measure alkaline phosphatase activity using PNPP in my mutant bacteria strains, but all the protocols I found involve purification of the phosphatase (which I have no need of).
Does anyone ...
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1answer
107 views
Protein construct design
I am trying to create some constructs of a certain protein deleting well defined domains (at either terminus) to determine interaction regions with other proteins etc., 3 constructs with varying ...
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1answer
129 views
Does cooking ginger reduce its anti-nausea effect?
There seems to be strong evidence to support the hypothesis that eating ginger helps reduce nausea e.g. during pregnancy (e.g. Vutyavanich et al.). It seems that gingerol is the active ingredient in ...
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3answers
128 views
How can I produce milligram quantities of an isotope-labeled DNA oligomer?
I'd like to produce a specific DNA sequence on a milligram-scale and 13C15N-label it. The sequence is around 35 nucleotides long, so chemical synthesis is out due to the exorbitant costs.
I'm also ...
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2answers
67 views
Should we be looking for extra-terrestrial life on comets?
I have just read What elements are a possible basis for life? and I find myself wondering whether instead of seeking advanced life-forms at remote locales a La SETI, and perhaps fundamentally ...
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1answer
109 views
Making penicillin using animals - specifically, a goat
In the scifi novel Lucifer's Hammer, one of the characters (a biologist, if I remember correctly) finds himself in a post-apocalyptic world and tries to make penicillin to save his own life. To do ...
7
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1answer
135 views
When collecting cell lysates for a Western blot, how do I induce di-sulfide bonds?
I would like to conduct a simple dimerization experiment for some protein I'm collecting from a cultured cells. My thought is, that if I'm running a non-reducing, denaturing PAGE gel, then removing ...
7
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1answer
93 views
What role does a protein's size have on protein-protein interactions?
Protein-protein interactions are when two or more proteins bind together, possibly for some important biological function. Recently, I'm starting to look more into proteins, and in particular, ...
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1answer
92 views
How Antioxidants affects Human Metabolism?
I'd like to know how antioxidants affects the human metabolism and which ones are essential for metabolism processes.
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1answer
147 views
How do plants 'tell time' for circadian rhythms based on a ~24 cycle?
I've read that many plants have some sort of circadian rhythm where they perform a certain action on a cycle of about 24 hours, like the mimosa plant opening and closing its leaves. Obviously this is ...
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0answers
53 views
Can jellyfish improve Black Sea environment?
According to this study, cited by many popular science magazines, jellyfish and other, smaller animals can contribute to the vertical ocean stir as much as currents do.
Black Sea chemistry and ...
6
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2answers
310 views
What is the correct model for enzyme-substrate complementarity?
This Wikibook shows both proposed models of enzyme-substrate complementarity, the Lock and Key model and the Induced Fit model. I've always been taught that the Induced Fit model is the proper one. ...
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1answer
76 views
When giving blood, what is the specific Iron measurement they take?
I went to give blood the other day, and they take an "iron" measurement prior to actually drawing the blood. My level was 16.4 -- but what specific type of iron were they measuring?
I've heard of ...
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1answer
940 views
Why does Rigor Mortis occur after death?
After someone dies they become stiff, this is termed Rigor Mortis and happens because the cells run out of ATP (I think). But why do the cells need it to remain flexible?
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1answer
320 views
HDL- and LDL-cholesterol
Why exactly are HDL-cholesterols good for us and LDL-cholesterols not. I know LDL-cholesterols cause Atherosclerosis and that HDL-cholesterols removes the excess of LDL-cholesterols, but from a ...
6
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2answers
263 views
For how long and how cold should I perform ethanol/isopropanol precipitations of RNA or DNA?
Precipitating nucleic acids using either isopropanol or ethanol is a very common operation, and I've read some very different protocols on the duration and temperature the precipitation should be ...
6
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2answers
58 views
Is there a binding affinity metric for interactions not in equilibria?
I am investigating the strength of binding of a small peptide to a protein by isolating the bound version and subjecting it to collisions with gas molecules (CID mass spectrometry) to dissociate the ...
6
votes
1answer
95 views
Determining if a specific proline is cis or trans in the protein?
While peptide bonds usually adopt the trans conformation, peptide bonds to proline can exist in either cis or trans conformation. The isomerization between cis and trans is slow, and has been shown to ...
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1answer
115 views
What is the origin of “melting” in molecular genetics?
I'm reading some papers about prokaryotic transcription mechanisms, and I've come across a term I haven't heard before: DNA melting or promoter melting. After reading a bit, it's pretty clear that ...
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1answer
332 views
Basic Amino Acid Residue Binding Mechanism to DNA
I understand that many protein DNA binding domains bind to DNA via basic residues such as Arginine and Lysine. But what is the mechanism used to bind to DNA and where on the DNA would these residues ...
6
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1answer
1k views
Does consuming sodium benzoate (preservative E211) cause problems during pregnancy?
There seems to be strong evidence to support the claim that sodium benzoate (E211) causes hyperactivity in young children, e.g. Bateman et al. (2004) and McCann et al. (2007). This leads me to ...
6
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1answer
147 views
Decreasing the alcohol proof and faster in hangover, why?
My russian friend says that the USSR agents used/use the trick that they offered the victim first vodka and then last wine.
I have noted that this puts you faster to hangover: decreasing the alcohol ...
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2answers
160 views
Why is absorbance at 280 nm for protein solution going up when I measure repeatedly?
I have been measuring my protein solutions' concentrations by diluting them in water 20 fold with a final volume of 100 uL and then measuring the absorbances of these solutions in 96 well plates with ...
6
votes
1answer
382 views
How does water buffer a sudden drop in temperature?
A property of water is that it is slow to heat and cool. According to my biology book, some energy from an increase in temperature would spent breaking hydrogen bonds, so that temperature does not ...
6
votes
1answer
178 views
How to prevent protein precipitation?
I'm trying to label a protein with fluorescent dye (TMR succinimidyl ester), but having trouble getting the protocol to work.
The protein seems to be stable in distilled water at a the recommended ...
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2answers
274 views
Why insects are so energy-efficient while flying?
Why are insects so energy-efficient while flying? Is it because of their light weight and aerodynamics or due to very efficient biochemical transformations (food->energy)?
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1answer
101 views
Is there an enzyme for the transformation of the hydroxyl group?
I would like to know, is there any enzyme which does the transformation of hydroxyl group to any other functional group using the enzyme.
The substrate is aromatic hydroxyl group. Product should not ...
5
votes
1answer
188 views
What are the units of enzyme activity?
I was looking at this graph of turnip peroxidase activity and I saw that they use units of 1/sec for enzyme activity. What does this unit intuitively represent and how is it calculated?
5
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1answer
144 views
Are the cytosol and extracellular fluids electrically neutral?
I've found several sources that state that overall, the cytosol of a cell is electrically neutral. The extracellular fluid is also purportedly electrically neutral. How can that be when we have ...
5
votes
1answer
64 views
In which way would the yeast cell cope with the excess amount of methionine in the growth media?
I guess that when there is surplus of methionine in the cell it is incorporated in the TCA cycle as a succinyl CoA, with cysteine as a by-product. But now the cell has the surplus of cysteine. What ...
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2answers
287 views
Isotype control antibodies in Flow Cytometry
In a Flow Cytrometry, one can add an Isotype Control Antibody to allow another antibody to bind more specific to the cells.
My question is, how can the Isotype Control Antibody add specificity to the ...
5
votes
1answer
112 views
Are quaternary protein monomers unique to a particular protein complex?
I know that quaternary protein structures are formed exclusively via non-covalent bonds. My biochemistry professor discussed a viral capsid that is essentially one quaternary structure with 240 ...
5
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1answer
682 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 ...
5
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1answer
103 views
How to Design an siRNA Experiment?
I'm going to undertake an siRNA experiment soon, but I have only read about them. I want to address the role an enzyme plays in processing a protein.
From what I understand, I will need to pick two ...
