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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776 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 ...
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1answer
120 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 ...
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1answer
258 views
Very high 260/230 absorbance ratio of an RNA sample
After my most recent RNA extraction, the RNA samples had very high 260/230 absorbance ratios, (ranging from 5 to 25).
I've never gotten numbers like this and I know the ratio is supposed to be ~2 in ...
5
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1answer
129 views
Using ion-exchange chromatography to purify DNA from a cell extract - Is DNA more negatively charged then RNA?
When applying this method we have a glass or plastic column of resin which is positively charged. Then we pour cell extract into the column in order to capture the negatively charged particles which ...
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63 views
Pharmacologically, can tricyclic antidepressants have a side-effect profile similar to neuroleptics?
Torticollis (wryneck, cervical dystonia) is a neurologic movement disorder causing involuntary muscle spasms in the neck. Often, neuroleptics can cause such a side effect. I'm wondering if this ...
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2answers
283 views
Does ethanol destroy RNase?
I've gotten conflicting advice on this: some people believe one can remove RNase contamination simply by spraying the bench, pipettes, gloves, etc. with ethanol. Others think ethanol does not destroy ...
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2answers
193 views
DNA as an acid? [duplicate]
Possible Duplicate:
Does DNA react in all of the ways most other acids do?
Even if DNA is made up of nucleotide bases, it is said to be an acid. Why is this?
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1answer
117 views
If proteins have an overall charge, how do membrane proteins traverse through the hydrophobic region of the plasma membrane?
These two concepts seem almost contradictory, proteins have a net negative charge due to the amino acids in them each having a small negative charge, yet membrane proteins are able to exist traversing ...
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1answer
78 views
Why isn't there any repulsive force between Na+ and K+ disrupting thier roles in transmembrane voltage/ action potentials
Pretty self explanatory question. I have a basic grasp on the "How" and "Why" of Reversal/Action Potential in and between neurons, but this question lingers.
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2answers
133 views
Differences Between Protein Motifs and Protein Domains?
I am in a 300-level molecular biology class and am unclear about this concept and how to delineate motifs versus domains of proteins. Any suggestions would be much obliged.
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1answer
71 views
What causes humans to be sleepy?
Is there a hormone or group of hormones that regulates when we feel sleepy late at night, or in the morning? Or is sleepiness caused by some other non-hormonal mechanism? (e.g. pure psychological, ...
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3answers
161 views
Biological Pathway of Lipid Hypothesis
I've read a lot on both sides of the debate of low carb vs low fat diets trying to make some sense of what is being proposed. The lipid hypothesis runs roughly along the lines that we have lots of ...
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1answer
37 views
Photosynthesis regulation
I read about the regulation of Calvin cycle by thioredoxin which activates key enzymes essentially by converting disulphide linkages on inactive enzymes into sulfhydryls. Another regulatory mechanism ...
4
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1answer
146 views
Why is second pKa value of phosphoric acid different across different sources?
Am I missing something very fundamental here for phosphoric acid's second pKa value?
I check the Wikipedia page and these are the values: (1) 2.148, (2) 7.198, (3) 12.377
Then I check Sigma-Aldrich ...
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1answer
52 views
How is respiration an unbalanced equation
The equation for respiration is C6H12O6+6O2→6CO2+6H2O+36ATP. The chemical formula for ATP is C10H16N5O13P3. How is this possible, since it violates the law of conservation of mass because it is ...
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1answer
62 views
Are there any websites offering graphs for the light absorption of different enzymes?
I have found graphs for the light absorption of water, haemoglobin, lipids, melanin, etc., but I am having a hard time finding graphs about enzymes.
Are there any websites or other reference sources ...
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1answer
185 views
Why are omega-3 fatty acids so easily oxidized when they're incorporated in cellular membranes?
Apparently, this has led to results with clinical significance, as we can see at http://extremelongevity.net/2011/10/03/daily-fish-oil-consumption-may-reduce-lifespan/...
The researchers fed a ...
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1answer
273 views
Conversion rate of topical Retinol to Retinoic Acid (Tretinoin)?
I'm wondering if someone out there has more information than me. Retinoids have well known metabolic pathways in vivo, and it's usually something like: ...
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1answer
118 views
Are there any intersections between the biochemical pathways of uracil biosynthesis (or metabolism) and methionine degradation in eukaryotes?
Is there any way in which uracil biosynthesis or metabolism could help cell in degradation of toxic levels of methionine?
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2answers
93 views
Why does Glutamine have the symbol Q?
Spent a half hour googling this and the best I could find was this:
Now for some rhymes: Arginine = R. R we having fun yet?
Asparagine = N The kNights of Ne say "Ne".
Glutamine is a cute ...
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1answer
46 views
Why is funnel web spider venom so lethal to humans and not so much for other mammals?
According to the information from this article,
People and other primates are exquisitely sensitive to funnel web venom but, intriguingly, other mammals such as mice, rabbits, guineapigs, dogs ...
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3answers
134 views
Why do neurones use chemical signalling at synaptic junctions?
Problem. When a neurone fires, it sends an electrical signal that jumps down the axon via the nodes of Ranvier very rapidly. At a synaptic junction, chemical brownian diffusion signalling with ...
3
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1answer
81 views
How does ethanol interact with insulin?
I know that ethanol increases insulin secretion--could someone explain why?
All I have found till now is experimental data analyses. I am interested in mechanism of alcohol consumption.
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1answer
91 views
What is the molecular basis of hangovers?
Well, most of us have experienced the wonderful feeling of the dreaded hangover. How does it work exactly? I imagine it has something to do with dehydration but what are the underlying mechanisms?
...
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3answers
74 views
Is DNA mutation locally energetically stabilizing the DNA molecule
I am no biologist, but as a physicist, a spontaneous mutation (seen as a chemical transformation) should lower the energy of the system, at least locally. So I wonder if any research has been done ...
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1answer
420 views
What are the units of Q10 (temperature sensitivity)?
Q10 is the increase in a rate (e.g. activity of an enzyme) observed with a 10 degree temperature increase.
According to Wikipedia:
It is apparent that the units of R (e.g. mol/g/s) cancel out, ...
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1answer
183 views
Troubleshooting bioconjugates migration in a SDS-PAGE gel?
We do a lot of bioconjugation chemistry (click chemistry in particular but also NHS and Maleimide chemistries). Our method to valid the conjugation reactions have been to use SDS-PAGE gels followed ...
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1answer
42 views
What molecular processes are involved in pseudopodial extension?
I am curious as to the processes and mechanisms involved in the extension of pseudopodia in amoeba. How does the cell know and control the direction and extent of pseudopodia formation at a molecular ...
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2answers
38 views
What software is there available for Quantitative structure–activity relationship (QSAR) pharmacological studies?
QSAR modelling in pharmacology basically hangs on using mathematical modelling to approximate the effects different molecules will have on various pharmacological targets. I would like to know what ...
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1answer
63 views
Can compounds be predicted from Polyketide synthases gene clusters?
I've seen a few talks on the subject. From a gene cluster, there is some decent ability to determine which domains contribute to certain functional groups in the final metabolites. It sounds like this ...
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1answer
156 views
Ammonium sulphate precipitation assay pH dependence
In general does the pH effect the precipitation, e.g. would a pH of 6 cause less precipitation than pH 7.5. Or are they unrelated?
3
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1answer
843 views
Does mixing alcoholic drinks really make you more drunk?
There is plenty of anecdotal evidence ("beer after wine and you'll feel fine, wine after beer will make you feel queer") that mixing alcoholic drink types leads to a stronger effect, but I can't find ...
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2answers
315 views
Simple diffusion of lipid-soluble molecules through phospholipid bilayer — does anything get “stuck” in transit?
It's a pretty elementary concept, and when I first learned of it I don't think I had the foundations to even think of such a question, but I found myself the other day thinking about the amphipathic ...
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1answer
55 views
How do multiple replication forks function without 'colliding', and what is the benefit of this method?
I'm currently reading a little about DNA replication, and have come accross the following statement;
Replication starts from a fixed point and is bi-directional ... In Eukaryotes, there are ...
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1answer
44 views
How can you improve solubility of colloidally dispersed substances?
If you solve collidally dispersed substances then the particles can form large colloids. This may block narrow passages and diffusion into dense structures may become completely impossible.
What can ...
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0answers
61 views
What causes adenosine build up in the brain when awake?
Adenosine is an important hormone in sleep regulation. It is postulated that when a person is awake, there is a build up of adenosine in the brain, which inhibits the neurons in the brain, and ...
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0answers
16 views
Does Doxylamine have any Influence on the Monoaminergic System?
Does doxylamine have any affects on the monoaminergic system? Specifically I am interested in adrenergic or serotonergic activity but additional information on its dopaminergic activity won't hurt ...
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3answers
98 views
Michaelis-Menten Kinetics: Does measuring apparent Km and Vmax take into account competing reactions?
I am learning about why it is important to measure Km and Vmax for each experimental setup because measuring the "apparent" Km and Vmax includes enzyme inhibitions of which one might not be aware.
...
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3answers
62 views
Histidine aromaticity
I understand that the imidazole ring in histidine is aromatic. I also realize that it retains it's aromaticity when protonated.
I am wondering why it is not mentioned at all in basic text books such ...
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1answer
193 views
Melting point of a fatty acid?
What factors determine the melting point of a fatty acid?
Chain length
The number of methylene group
The ionized state of the fatty acid
Its degree of saponification
Its ability to alter the ...
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votes
2answers
96 views
What exothermic reaction distinguishes warm blooded animals?
I would appreciate an answer specifically in the form of an exothermic chemical reaction. Namely, the one primarily responsible for generating heat in warm blooded animals that does not take place in ...
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votes
2answers
54 views
What chemicals can be detected from one's sweat?
This question came to mind after reading this article. The article speaks of inducing sweating to determine by a roundabout fashion the amount of salt therein. I'm no medic but I find myself wondering ...
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1answer
114 views
Negative feedback in the fructose metabolism in liver
What happens in liver when large amount of fructose is consumed?
I vaguely remember my biochemistry lecturer telling us that the enzymes that process fructose in the liver does not have negative ...
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1answer
183 views
Does caffeine increase the speed at which sperm travels?
I'm not even sure if this claim is true, but...
This source states that
Caffeine gives both types of sperm a boost, but the Y-sperm would get a little more of a boost.
This article reinforces ...
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1answer
326 views
What is the reaction mechanism of dopamine hydroxylase converting dopamine to norepinephrine?
The reaction is basically shown below. Dopamine hydroxylase is an enzyme, so I'm not sure if we can have a theory based on organic chemistry. On the other hand, maybe there is a theory that involves ...
2
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1answer
33 views
What does “rapamycin-sensitive oncogenic transformation” mean?
Can someone explain exactly what "rapamycin-sensitive oncogenic transformation" is? I get that it's a drug that suppresses the immune system but what does it have to do with oncogenic transformation?
...
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votes
3answers
50 views
What biochemical molecule viewer allows for changes in amino acids and resulting tertiary structure?
I am familiar with the Jmol, Rasmol and PyMoL softwares, and was recently introduced to BioBlender. However, I am completely unaware if any of these programs (or others) are capable of loading a .pdb ...
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1answer
52 views
Diet of free-range herbivores
Giving minimal credence to estimates in popular media of the average biomass of insects/arachnids, etc. in an acre of land, it seems that a "free-range" cow (I don't mean to pick on cows) might be ...
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1answer
13 views
Why is allolactose the LacI inducer?
For what reason(s) is allolactose, instead of lactose, the "natural" inducer of lac operon repressor?
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1answer
27 views
Are CoA and CoAS the same thing in a compound?
Is CoA-S-R the same as CoA-R, and is CH3C(=O)CoA the same as CH3C(=O)SCoA? Eg. Above is the compound on the right just coenzyme A or is it actually another compound and not just notation?
