The study of chemistry within the scope of biology: the compounds that occur and the reactions involving them in living organisms.

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1answer
82 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
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2answers
719 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
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1answer
114 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
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1answer
116 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
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1answer
101 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 ...
11
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3answers
1k 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
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1answer
1k 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
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1answer
113 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 ...
4
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1answer
130 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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0answers
49 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
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2answers
264 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
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0answers
131 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
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1answer
240 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
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1answer
2k 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
329 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
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1answer
57 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 ...
4
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1answer
210 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
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1answer
284 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
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1answer
114 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
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1answer
321 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 ...
4
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1answer
101 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
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1answer
802 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
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2answers
78 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
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1answer
655 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
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2answers
2k 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
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1answer
253 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
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1answer
234 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 ...
9
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1answer
262 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 ...
4
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1answer
3k 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
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1answer
80 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
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1answer
240 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?
7
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1answer
222 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 ...
7
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1answer
436 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
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1answer
115 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 ...
2
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3answers
79 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 ...
0
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1answer
397 views

Is breathing in deodorant fumes dangerous for my brain?

I noticed that I sometimes get dizzy when I accidentaly breathe in too much Axe. Also, I find the smell of alchohol rich deodorants quite unpleasant. But, I was wondering, is it actually dangerous? ...
7
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1answer
132 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 ...
5
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3answers
224 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 ...
4
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1answer
89 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.
5
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1answer
300 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?
9
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1answer
2k 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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0answers
65 views

When should endocytosis inhibitors be used in cell binding assays?

I'm beginning to do some cell-binding assays and I would like for my proteins to not be endocytosed by my mammalian cells. Typical suggestions are for the cells to be kept on ice and that the binding ...
5
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2answers
648 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 ...
7
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3answers
221 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 ...
8
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2answers
2k views

What is the concentration of ATP in an average cell?

Can someone give me some references showing the average concentration of ATP in a cell?
13
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2answers
752 views

Is the EC50 of an activating protein for an enzyme a good indicator for the binding affinity Kd?

We work with a membrane protein system where measuring the affinity between the enzyme and the upstream activating protein has been difficult, and when measured in detergent solution, it is almost 100 ...
10
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1answer
336 views

How would I explain different properties of the same protein in different species?

I recently finished an experiment where I analyzed the rate of ATP hydrolysis of Heat shock protein 104 in three species of fungi. They have shown to all have different rates of ATPase activity. How ...
7
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2answers
262 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 ...
9
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2answers
126 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
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2answers
497 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)?