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
135 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 ...
10
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3answers
24k 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 ...
10
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2answers
755 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 ...
10
votes
1answer
606 views

Why does gluconeogenesis need to exist - it seems pointless?

The gluconeogenesis pathway seems quite pointless to me. I don't understand why an organism would want to spend energy to create a molecule that can then be metabolized again for less energy? The ...
10
votes
1answer
535 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 ...
10
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2answers
983 views

Why does Hunger lead to the aggressive behavior?

I have observed that frequently when people are hungry; they tend to get angry more easily on pointless issues. Does this mean that our fight or flight response is more active when a person is hungry? ...
10
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3answers
201 views

Formation of Life

Originally, life evolved from non-living matter. Why is life only generated from other life nowadays, and why doesn't it evolve from inanimate matter, like it did originally billions of years ago, ...
10
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1answer
174 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 ...
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3answers
1k 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 ...
10
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2answers
8k 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 ...
10
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1answer
392 views

What are the olfactory chemicals in whiteboard/permanent markers and what do they bind to in the nose, lungs, and brain?

What are the olfactory chemicals in whiteboard/permanent markers and what do they bind to in the nose, lungs, and brain?
10
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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 ...
10
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1answer
116 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
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2answers
350 views

Which sequence characteristics influence the transcription efficiency of T7 polymerase?

The T7 polymerase doesn't transcribe all sequences equally well, the transciption efficiency can vary widely for different sequences. One well known requirement of the T7 polymerase is that the ...
9
votes
3answers
226 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 ...
9
votes
1answer
640 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 ...
9
votes
4answers
257 views

How can I avoid digesting protein-bound DNA?

I'm interested in sequencing and analyzing the bound DNA, and minimizing the amount of unbound DNA that gets sequenced through digestion. When digesting protein-bound DNA, is all of the unbound DNA ...
9
votes
1answer
375 views

Does the cell internal temperature changes in response to a change in external temperature?

Background Some species are homeotherm (internal temperature is not affected by a change in external temperature) and some are poikilotherm (internal temperature changes in response to external ...
9
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1answer
125 views

Why pouring salt in the wounds is painful?

Pouring salt in the wounds is so painful. I am sure you all experienced this. whats happend there?
9
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2answers
171 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, ...
9
votes
1answer
745 views

Why is the brain dependent on glucose?

The strict dependence of the (human) brain on glucose has always been puzzling to me. While ketones can substitute for a portion of the brain's energy needs, it cannot substitute completely: blood ...
8
votes
3answers
223 views

Can elements of one's environment act directly as hormones?

Can pollution and things in an organism's environment serve as hormones?
8
votes
3answers
744 views

What triggers meiosis in gonadal cells?

What specific biochemical processes are involved in inducing meiosis rather than mitosis? Why are gonadal cells the only cells in the human body which do undergo meiosis?
8
votes
1answer
859 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
2answers
8k 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 ...
8
votes
2answers
7k 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?
8
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1answer
284 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 ...
8
votes
2answers
421 views

Can a living organism run on electricity?

Each time I'm too lazy too cook I think it'd be cool to be able to just plug myselt into an outlet. Yet I know it is not possible - I need amino acids and a lot of other stuff that electricity can't ...
8
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2answers
5k views

why is AUG the initiation codon?

Is there any reason why AUG is the initiation codon ? Why is there a need for an initiation codon ? Can't translation start with different codons?
8
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1answer
96 views

What are the variables that control/influence the color of oranges(Citrus sinensis)?

I hear that Oranges cultivated in tropical areas of the world tend to be greener when ripe, is that correct? Even the same type of Orange differs in color if cultivated in California or Florida. I ...
8
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1answer
52 views

How does membrane potential vary between intraceullar membranes and the cellular membrane?

Question Does each type of membrane have a different membrane potential? I'm especially interested in answers that can cite academic papers that have attempted to measure membrane potentials. ...
8
votes
1answer
9k 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
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1answer
90 views

Why do humans require vitamin B12 supplementation while herbivores do not?

This question came about from reading the comments of this (very unclear) question, which the author did not properly clarify. Vegans are often recommended to take vitamin B12 supplements, as the ...
8
votes
1answer
144 views

Basic question about multiplex PCR

Let's say I have a DNA sequence with the following structure: $$ 5' - N_n - S_1 - N_{1000} - S_2 - N_{1000} - S_3 - N_n - 3' $$ Here, the $N$s represent stretches of arbitrary sequence of the ...
8
votes
2answers
85 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 ...
8
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2answers
244 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 ...
8
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2answers
60 views

What are the ecological effects of moderately high and prolonged concentrations of nitrogen deposition on an ecosystem?

There are many sources of nitrogen which eventually get deposited out of the atmosphere and onto the land/surface. Typically higher levels of nitrogen compounds are emitted near urban and roadway ...
8
votes
1answer
464 views

What biological processes cause leaves to change colours in Autumn?

I am curious to learn what are the biological mechanisms that cause leaves of deciduous plants to change colour? What happens to the chlorophyll? What environmental phenomena (temperature/air ...
8
votes
1answer
860 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 ...
8
votes
1answer
408 views

How do the pharmacodynamics of the NSAIDs differ and are there “resistant” COX phenotypes?

I know that the non-steroidal anti-inflammatory drugs (e.g., aspirin, ibuprofen, naproxen) affect the enzymes cyclooxygenase (types I and II). Is there any difference in the degree to which these ...
8
votes
1answer
261 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 ...
8
votes
1answer
433 views

What is the difference between organelle membranes?

Cells and organelles are contained in lipid bilayers. I'm particularly interested in eukaryotic organelle bilayers and the biophysicochemical differences between them. Many papers assume a ...
8
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0answers
150 views

Why do bananas go brown quicker in the fridge?

Perhaps the title should be: Why do specifically bananas go brown quickly when left in the fridge? Bananas go brown over time because of the oxidation of phenol residues. Bananas go brown quicker ...
7
votes
2answers
974 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)?
7
votes
3answers
284 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 ...
7
votes
3answers
127 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
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2answers
524 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 ...
7
votes
1answer
207 views

Is fluoride toxic, and how worried should I be about it?

A recent flurry of "fluoride is bad!" posts are appearing on my social network news feeds. Usually I can simply ignore them after a brief look, but this one, stemming from a recent article in The ...
7
votes
1answer
5k views

What is/are the molecular differences between HDL and LDL cholesterol?

Why exactly is HDL-cholesterol good for us and LDL-cholesterol bad for us. It has been well-established that LDL-cholesterol is associated with atherosclerosis and that HDL-cholesterol helps remove ...
7
votes
1answer
610 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 ...