The function of chemistry within the scope of biology; the study of the compounds that occur, and the reactions involving them, in living organisms.
6
votes
2answers
169 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 ...
3
votes
2answers
36 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 ...
4
votes
1answer
126 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 ...
28
votes
4answers
2k views
Why 20 amino acids instead of 64?
This question got me thinking about amino acids and the ambiguity in the genetic code. With 4 nucleotides in RNA and 3 per codon, there are 64 codons. However, these 64 codons only code for 20 amino ...
1
vote
0answers
35 views
Why does trans fat decrease hdl's?
I understand that cis fats increases hdl's, and unsaturated fat increases ldl's, but trans fat increases hdl's and it decreases ldl's. Why does trans fat do this?
10
votes
1answer
180 views
Why do we feel tired if we sleep excessively?
When we eat, finally we feel full. I know which mechanism causes the sensation of being full. But when we sleep excessively we often still want more sleep. Why does this happen? Is there a mechanism ...
1
vote
0answers
18 views
Glutamine analysis
I use to run a method to analyse all the aminoacids in a food sample. For that I have to hydrololyse the sample and in the last stage of the method I read the amino acids with a ion exchange ...
4
votes
1answer
44 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 ...
7
votes
0answers
54 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 ...
0
votes
0answers
42 views
Bradford Protein Assay [closed]
Please would somebody help me to solve the following exercise:
Determine the protein concentrations of the four unknown samples (A,B,C,D) using the raw data obtained from a Bradford assay.
...
3
votes
1answer
51 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 ...
1
vote
0answers
42 views
Solid phase use in HIV rapid tests
I have another question in regards to my HIV test research. The rapid tests like Orasures Oraquick contains a strip of synthetic peptides that are used to represent proteins found in the envelope ...
3
votes
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 ...
2
votes
1answer
49 views
Which Enzymes are Responsible for the Biodegradation of Noladin Ether?
Which enzymes degrade the CB1-specific endogenous cannabinoid 2-arachidonyl glyceryl ether? (Noladin ether)
2
votes
1answer
17 views
Which Enzymes are Responsible for the Biodegradation of Beta-endorphin?
Which enzymes are responsible for the biodegradation of the endogenous opioid peptide, beta-endorphin?
-2
votes
1answer
34 views
Good place to ask health based questions? [closed]
I like the development of biology.stackexchange.com, but it is still in an early stage and far from perfection. While we develop it further, could you guys help me finding places to ask questions ...
10
votes
3answers
257 views
Where does the 'C' in exhaled CO2 mostly come from?
When a human being exhales $CO_2$, what is, by the numbers, the main source of carbon atoms exiting the body in this way? I mean what class of cells, or which tissues are the biggest on a pie chart of ...
7
votes
2answers
144 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 ...
3
votes
1answer
57 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 ...
11
votes
1answer
229 views
How much energy does human body fat contain?
I have been reading the Wikipedia article about food energy, but as I'm not a biologist, I don't really understand it properly, so I came here to ask you guys.
My question is: If a human body needs X ...
10
votes
1answer
73 views
When running a gel, what could cause a standard to run “faster” than usual?
We are running a gel on the products of a restriction digest to determine the size of an insert. We know the vector backbone size should be ~2.9kb; however, the standard appears to be running too ...
3
votes
1answer
78 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.
7
votes
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 ...
1
vote
0answers
72 views
Is eating salt dangerous for the brain?
I read somewhere that eating a lot of salt will raise blood pressure, which will in turn damage brain tissue. This is because water molecules gather around salt ions, thus making it harder for the ...
6
votes
1answer
325 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 ...
2
votes
0answers
35 views
Do humans have chemosensors for nutrients or chemicals?
I'm reading about chemoreceptors on Wikipedia, and see that the typical ones are mentioned: taste, smell, co2. I would like to learn more about the other kinds of chemoreceptors that humans may ...
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 ...
0
votes
2answers
90 views
Why do living organisms replicate itself or procreate
Why do living organisms spontaneously replicate itself or "procreate" (my understanding is that it does).
From a uni-cellular and micro-organism point of view. Is there some sort of stimulant in the ...
5
votes
2answers
290 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 ...
4
votes
1answer
233 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: ...
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 ...
2
votes
0answers
63 views
Virucides - Herbal and otherwise, for HHV6 type virus or any inner-cell virus
Does anyone know where I can find a reliable list of virucides (not anti-virus) that can be used by humans? This virucide must be able to affect viruses that are already inside the cells. St John's ...
11
votes
1answer
111 views
How would one calculate the availability of nucleotides to an enzyme?
How would one calculate the availability of nucleotides to an enzyme like a polymerase ?
I imagine an answer in units like nucleotides per second per enzyme, but I'm also imagining an answer that is ...
2
votes
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 ...
5
votes
1answer
136 views
$S_{0.5}$ vs $K_m$ values in enzyme kinetics
What is the difference between $S_{0.5}$ values and $K_m$ values in enzyme kinetics?
3
votes
1answer
88 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?
...
1
vote
1answer
56 views
What are the biochemical interactions between human body and Polyethylene?
Our waterways and oceans are showing increased levels of plastic contamination. These plastics are breaking down into smaller pieces. When one goes to the beach and plays in the surf they often ...
24
votes
4answers
600 views
Human perception of time depending on age
From what I can tell and what thus far all people with whom I discussed this subject confirmed is that time appears to "accelerate" as we age.
Digging a little, most explanations I found basically ...
13
votes
1answer
2k views
What effect has changing pH and salt concentration on protein complexes?
I'm struggling to find peer reviewed literature that explains the effect of changing the pH and the salt concentration on protein/protein complexes in solution. What effect does the pH and the salt ...
0
votes
0answers
62 views
What happens to proteins when they absorb UV? [closed]
I know that proteins strongly absorb UV at 280 nm.
I have 3 questions:
What happens to proteins when they absorb UV?
Do different proteins absorb different wavelengths ?
Does water absorb UV as ...
4
votes
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 ...
7
votes
2answers
68 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 ...
7
votes
1answer
262 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 ...
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 ...
4
votes
2answers
185 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?
3
votes
1answer
149 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?
4
votes
1answer
115 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 ...
8
votes
1answer
157 views
Does DNA react in all of the ways most other acids do?
As I understand it from my basic chemistry, there are some fundamental reactions that exist between any acid and other substances for example acid-base reactions that form a salt, and the existence of ...
3
votes
1answer
744 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 ...
5
votes
1answer
65 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 ...
