The function of chemistry within the scope of biology; the study of the compounds that occur, and the reactions involving them, in living organisms.
7
votes
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, ...
5
votes
2answers
277 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)?
8
votes
3answers
2k views
Why can't the brain and red blood cells use fuels other than glucose?
The question is rather straight forward: I have always been curious as to why, but cannot find an explanation online.
I can imagine that the mechanism is different for each, but why does brain tissue ...
14
votes
2answers
917 views
Why is glucose our primary source of energy?
Is there any evolutionary reason for glucose being the "main" molecule used as a source of energy, beginning with glycolysis and subsequently cellular respiration (after being converted to two ...
2
votes
1answer
111 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 ...
15
votes
4answers
706 views
Why are there exactly four nucleobases in DNA?
Does someone know why DNA is composed of four nucleobases? In particular, is there an explanation for the number? Why four and not two, or eight?
8
votes
1answer
183 views
Why does hair turn grey or white, and why does it happen later for some?
The question is pretty simple: what is happening molecularly when hair turns grey or white? I would imagine that it is due to the lack of a particular compound. I'm also interested in why some ...
1
vote
2answers
227 views
How are proteins formed?
Somewhere, I have read that we need to consume proteins to make amino acids to make new proteins. What does it suggest? How do we make proteins from proteins?
3
votes
1answer
404 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, ...
2
votes
1answer
175 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 ...
5
votes
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 ...
6
votes
2answers
313 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. ...
3
votes
1answer
178 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 ...
1
vote
1answer
143 views
Which concentration of BSA is recommended for dynamic light scattering experiments?
What is the recommended concentration of BSA to be mixed with water so as to prepare a very dilute solution in order to clearly study the intensity-intensity correlation with single scattering ?
I ...
7
votes
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?
4
votes
1answer
163 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 ...
7
votes
1answer
95 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.
1
vote
1answer
85 views
How to manufacture different sized micelles in nano -scale?
I am trying to answer q5:
"How can you manufacture micelles in A) nanometerer -scale B) and in ten nanometer -scale?"
My Thinking
Observations and some thinking
Oil in ...
2
votes
1answer
148 views
What happens to colloidal particles in a liquid medium? And how to stabilize it?
Definition
Colloid is a dispresion of small particles of one material in another.
Definition 2 (Wikipedia)
A colloidal system consists of two separate phases: a ...
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 ...
6
votes
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 ...
17
votes
4answers
2k 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
...
7
votes
1answer
108 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 ...
5
votes
1answer
686 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 ...
2
votes
1answer
315 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 ...
10
votes
2answers
269 views
Could hydrogen replace oxygen in cellular respiration?
I was wondering what oxygen actually does in the body. I have seen a few answers to other questions that involve the electron chain and I am really not sure what that is. So I was wondering what ...
11
votes
3answers
414 views
What happens to dextrorotatory amino acids in humans?
As indicated by this question, most of the amino acids in the human body have the L-chirality. As enzymes also have handedness, what happens to the D-amino acids that end up within the human body? Are ...
10
votes
2answers
6k views
What is a coupled reaction and why do cells couple reactions?
I was wondering what exactly a coupled reaction is and why cells couple them. I read the wikipedia article as well as several others, such as life.illinois.edu but I still don't get it. Could ...
9
votes
2answers
1k views
Why is PEG important for efficient yeast transformation?
One way to do an yeast transformation is by using lithium acetate, a single-stranded carrier DNA, and PEG (1). I was wondering why is the polyethylene glycol important for the efficient ...
7
votes
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?
8
votes
2answers
151 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 ...
12
votes
1answer
240 views
How fast will cells lyse under hypotonic conditions?
Routinely, lysis of cells with hypotonic solutions is carried out along with some physical (douncing) or enzymatic (lysozyme) method to break open the cells. If one were not to do any of these and ...
11
votes
1answer
72 views
Does a theory exist for the formation of thylakoid structure?
I'm interested in how the structure of the thylakoid forms into its characteristic highly rugose stacks of grana. What causes the thylakoid to invaginate and self-associate, albeit with what appear to ...
7
votes
1answer
136 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 ...
9
votes
3answers
143 views
Does GFAJ-1 use Adenosine triarsenate as its energy currency?
Regarding the bacteria found in Mono Lake, CA that scientists believe uses or can use arsenic in its DNA backbone where life as we know it uses phosphorus (according to their experiments depriving the ...
6
votes
2answers
272 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 ...
8
votes
2answers
264 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 ...
6
votes
1answer
334 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 ...
2
votes
1answer
80 views
Structure of RAP Antibodies (Specifically RAP-5)
[EDIT] - Have just found not one but two papers that address my structure problem. However they concern RAP-1A, so I guess my question is now what is the difference in structure and function of ...
6
votes
1answer
956 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?
5
votes
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 ...
7
votes
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?
7
votes
1answer
334 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?
10
votes
1answer
124 views
What is the mechanism that directs myosin walking?
Myosin, dynein and kinase all "walk" towards specific ends of the microtubule or actin filament they are on. I'm most familiar with the walking mechanism for myosin, where ATP fuels conformal changes ...
8
votes
1answer
122 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 ...
6
votes
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 ...
7
votes
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 ...
8
votes
1answer
132 views
What are the biochemical processes occurring when food spoils?
Let's assume for a minute that microbes themselves and their direct toxic products (i.e. endotoxins) aren't toxic to humans. Let's also discount any innate immune responses the body mounts against the ...
16
votes
1answer
348 views
ATP cost for gene expression
How would you estimate the number of ATPs required to transcribe, export and translate a single eukariotic protein?
17
votes
3answers
134 views
How crowded is the bacterial cell?
I was wondering what is the protein concentration in an E. coli cell. When studying enzyme kinetics and activity in vitro, I would argue that the substrate and enzyme concentrations resemble those in ...
