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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3
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2answers
52 views

Tracking of oxygen molecules in glucose oxidation

For this reaction, found in typical biochemistry textbook: $C_6H_{12}O_6 + 6O_2 \to 6CO_2 + 6H_2O$ I am interested in where do the oxygen atoms of $6O_2$ go. I think they go to $6H_2O$, but this is ...
5
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1answer
77 views

Fermentation to acetic acid

How much time is needed for the fermentation to acetic acid production cycle, and the conversion of apple vinegar in a sealed container incubated at 37 °C? Should be in the fully closed? What is ...
4
votes
1answer
22 views

Phospholipid movement in cell membranes

What causes phospholipids to flow so quickly in cell membranes? In Biology by Cambell et al. they state that a phospholipids can travel up to 2 micrometers per second. Is that a random movement or has ...
5
votes
1answer
86 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 ...
2
votes
1answer
746 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 ...
13
votes
3answers
35k 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 ...
11
votes
3answers
2k views

Where does the 'C' in exhaled CO₂ mostly come from?

When a human being exhales CO₂, 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 ...
0
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1answer
124 views

Pathway mediates nitroglycerin-induced relief from angina pectoris [closed]

what kind of Pathway mediates nitroglycerin-induced relief from angina pectoris,please provide some idea...
47
votes
4answers
6k views

Why 22 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 22 ...
2
votes
1answer
52 views

What Biology topics are linked to the Nitrogen Cycle? [closed]

What other educational topics are linked to the Nitrogen Cycle? I am a Science teacher, and I need to organise my lessons. Thanks!
0
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1answer
37 views

Epitope annotated protein

What is epitope annotted protein?? The book from which I got this term is : http://www.springer.com/biomed/immunology/book/978-1-4939-1114-1
1
vote
1answer
56 views

How do the quantities of ATP formed during aerobic and anaerobic respiration compare? [closed]

How do the quantities of ATP formed during aerobic and anaerobic respiration compare?
1
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1answer
26 views

What are the reactions in the body that triggers dizziness after cigar(nicotine) smoking in non-smokers?

Suppose there is a person that has never used nicotine in any form in his/her life. Why does the person get dizzy after a few "shots" from a cigar(nicotine)? What's the difference between using other ...
1
vote
1answer
13 views

What enables azacitidine to incorporate into both DNA and RNA?

I did a mini-project on the drug azacitidine for my pharmacology class, and I learned that azacitidine has the ability to incorporate into both DNA and RNA. I think this is really unique because a ...
6
votes
2answers
252 views

HIV and effectiveness of inhibitor cocktail over single inhibitor

I'm looking for clarification on the answer to this question. It's in my biochemistry class but I figured this is more Biology than Chemistry, so I'm asking it here. The question is: One of the ...
3
votes
1answer
55 views

Is the activity of enzymes in the human body affected by the outer temperature?

I have to do a research about the enzymes in the human body and the things that affect them. I know that the body temperature affects the activity of enzyemes but I'd like to know if the outer ...
1
vote
2answers
60 views

Are triglycerides fat?

I have a quick question: Are triglycerides essentially what we call "fats"? I've tried reading up on it but there seems to be some conflicting information. Thank you.
1
vote
1answer
17 views

Help me understand my membrane potential assignment

Epithelial with the ability to transport NaCl is bathed in an isotonic salt solution with these values (in mM): 136 Na, 6 K, 140 Cl. The intracellular concentrations are: 45 Na, 100 K, 13 Cl. The ...
1
vote
2answers
58 views

How does high-fidelity of DNA replication depend on the formation of hydrogen bonds?

Replication has an error rate of less than 1 in 100 million. DNA polymerase forms H-bond with the H-bond acceptor atoms in the minor groove. <-- enhance fidelity here? Binding of the triphosphate ...
8
votes
1answer
238 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 ...
2
votes
2answers
66 views

peptide MHC microarray

"The recent technology is peptide–MHC microarray or artificial antigen-presenting chip. In this technique, recombinant peptide–MHC complexes and co-stimulatory molecules are immobilized on a ...
4
votes
2answers
449 views

Are there any multicellular forms of life which exist without consuming other forms of life in some manner?

The title is the question. If additional specificity is needed I will add clarification here. Are there any multicellular forms of life which exist without requiring the consumption (destruction) of ...
0
votes
1answer
40 views

Book-recommendation: Biochemistry

I need to have a book which covers following topics two may also be fine: (a) Structure and role of carbohydrates, fats, fatty acids and cholesterol, proteins and amino-acids, nucleic acids. ...
1
vote
1answer
43 views

Understanding intra and extracelullar concentrations (membrane potential)

I have 4 question (not homework) What happens to the cells membrane potential if: a) Na+ outside rises by 40mM b) K+ inside rises by 10mM c) K+ outside rises by 10mM d) A- (impermeable ion) ...
3
votes
1answer
61 views

NADH inhibits gluconeogenesis?

I was told in a physiology lecture that alcohol inhibits gluconeogenesis because 'NADH produced from ethanol catabolism leads to product inhibition'. But is NADH not a reactant coenzyme of ...
0
votes
0answers
29 views

Is there a known glucosepane cross-link breaker?

I read the following on wikipedia: There is, however, no agent known that can break down the most common AGE, glucosepane, which appears 10 to 1,000 times more common in human tissue than any ...
4
votes
1answer
58 views

Why is the ebola virus so intense now?

So i'm looking into the ebola crisis and it seems the death toll is really getting crazy. I understand that it's a cytomegalovirus and that it basically overwhelms the immune system due to it's size ...
2
votes
1answer
30 views

Why is coconut oil healthier when it has so much saturated fat?

I noticed that coconut oil has ~96% saturated fat, and I was under the assumption that saturated fats = bad for health. Why is it that coconut oil is healthier to alternatives with much less ...
12
votes
3answers
37k views

NADH vs. NADPH: Where is each one used and why that instead of the other?

I know NADH is used in cellular respiration and NADPH is used in photosynthesis. What difference does the phosphate group make that the same one isn't or can't be used for both? Is there a greater ...
2
votes
1answer
93 views

What is the result of meiosis?

Is the result of meiosis ONLY the sex gametes (male and female) which later meet to form a somatic cell? Sometimes I feel as if my book is hinting towards meiosis is the process where sperm cells meet ...
4
votes
3answers
139 views

Why can't you just take a vitamin? Why you need a healthy diet on top of that?

From what I understand, your body needs certain amounts of vitamins and minerals to maintain health. Why can't we just take enough pills to obtain these vitamins and minerals?
1
vote
1answer
99 views

Preservation of human tissue

At my med school we have human samples (body parts, organs, etc.) They are soaked in some sort of solution for long term storage. I'm quite sure that it's not formaldehyde as that would be really ...
0
votes
0answers
19 views

Formaldehyde turns plantar region of feet red?

I'm a freshman med student and I've noticed that on all the feet (and hands) of deceased people that I've worked with, the bottom of the feet always turns red and also the inside of the palm? Why is ...
3
votes
2answers
32 views

How does one determine intracellular concentration?

The TL;DR version Is there a fast way to determine what the cell environment of a particular cell (E.g RBC) is? (in terms of solute/ionic concentration) I'm not sure if the question belongs here, ...
-4
votes
2answers
76 views

How are atoms created? [closed]

From small baby to the old age, we will be grown. We are composed of bunch of atoms, multitude of atoms. When you are grown from baby to the teen age, everyone will say "he has grown!" What do you ...
2
votes
1answer
71 views

Fatty Acid Synthesis

I have a problem in my reasoning on the fatty acid synthesis in the human body. In the synthesis process you have this homodimer. So the synthesis starts with the transfer of a acetyl group from ...
2
votes
1answer
213 views

Independence of Light independent reaction in photosynthesis?

Inspired by a question asked to me by a classmate, I have the following question about Light-independent (dark phase) reactions in photosynthesis:- Let us suppose an algae sample was exposed to ...
2
votes
0answers
57 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 ...
1
vote
2answers
126 views

Plants without bacteria? is it theoretically possible?

I know from school, that all live on the Earth need bacteria as low-level "machines" that break down/extract/convert/produce chemical elements and combinations, other high-level organisms needed. But ...
1
vote
0answers
41 views

Ferredoxin synthesis pathways

I have been thinking about some alternative CO₂ fixation pathways. As almost all of them include ferredoxin reduction I started to wonder where does the ferredoxin comes from. I could not find any of ...
2
votes
2answers
52 views

Clarification on Hatch and slack pathway

The following is a minor clarification that I want to make, since it is rarely addressed directly in most of the texts I have gone through. In C₄ pathway, the chloroplasts are dimorphic, that is, ...
1
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1answer
43 views

All or nothing phenomena

We know that an action potential is produced by an active cell membrane when the stimulus reaches a certain threshold. When it does, an action potential fires, and when it doesn't, nothing happens. ...
4
votes
1answer
185 views

How many RNA-binding proteins can simultaneously bind on a single mRNA?

Typically, how many RNA-binding proteins can simultaneously bind to a single mRNA? Or said differently, how many "binding sites" does an mRNA have? What order of magnitude? I am interested in RNA ...
1
vote
1answer
26 views

How does fluorouracil inhibit pyrimidine synthesis?

I was reading in my pharmacology textbook about fluorouracil, and my book mentioned that fluorouracil is an antimetabolite whose function is to inhibit pyrimidine synthesis. However, I was curious to ...
4
votes
1answer
44 views

protein-binding sRNAs

I am actually a computational biologist, pardon me if my question description is a bit off-note, my curiosity is driving me on A bit of background and context: In bacteria, a regulatory protein ...
0
votes
0answers
18 views

Sequence based method for prediction of continuous B cell epitope

What is Sequence based method for prediction of continuous B cell epitope? What is the algorithm/procedure of this method? Can someone please explain this to me in simple language?
11
votes
2answers
314 views

How do antioxidants affect human metabolism?

I'd like to know how antioxidants affect human metabolism and which ones are essential for metabolic processes.
2
votes
1answer
18 views

Are the cpli and ctli tests time senstive(i.e. is it needed to test right away in order to get accurate results)?

I'm sending the blood samples to a lab and this takes some time until the actual testing. Some information on the tests. TLI : ...
1
vote
1answer
36 views

Can the sulphur content of biological material be reliably calculated from fat, fibre and protein contents (Weender Analysis)?

An often-used analysis of feedstocks for lifestocks is the Weender analysis, which basically divides the volatile solid content into fats, fibre and protein, as well as N-free matter. I found no ...
39
votes
4answers
20k 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 ...