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
203 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 ...
1
vote
1answer
67 views
What is the biochemical reason for mental fatigue?
Is it known exactly why the brain needs sleep? What's dropping low / going high when we experience mental fatigue? I can see why low glucose could result in mental fatigue, are other reasons known?
4
votes
1answer
147 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 ...
3
votes
2answers
39 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 ...
1
vote
0answers
38 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
212 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
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 ...
7
votes
0answers
55 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
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 ...
1
vote
0answers
44 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
38 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 ...
7
votes
2answers
169 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 ...
6
votes
1answer
91 views
Why does getting certain chemicals in cuts hurt?
More specifically, shampoo. What are the mechanics of detecting a noxious chemical stimulus in terms of which receptors recognise what, how do they do it, and how is this information relayed to the ...
3
votes
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 ...
10
votes
1answer
76 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 ...
10
votes
3answers
276 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 ...
11
votes
1answer
277 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 ...
1
vote
0answers
81 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 ...
3
votes
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.
2
votes
0answers
36 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 ...
0
votes
2answers
101 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 ...
2
votes
0answers
67 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 ...
6
votes
1answer
102 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 ...
6
votes
1answer
388 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 ...
5
votes
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 ...
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 ...
3
votes
1answer
92 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?
...
6
votes
1answer
143 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?
1
vote
1answer
57 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 ...
5
votes
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 ...
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 ...
4
votes
1answer
276 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: ...
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
314 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 ...
4
votes
2answers
194 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
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?
4
votes
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 ...
8
votes
1answer
160 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
846 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 ...
4
votes
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?
6
votes
1answer
83 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 ...
6
votes
1answer
191 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 ...
5
votes
0answers
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 ...
