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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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 ...
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2answers
56 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.
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14 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 ...
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43 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 ...
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222 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 ...
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62 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 ...
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64 views

How does protein denaturation work?

I was wondering how protein denaturation works. Are there covalent bonds, such as disulfide bridges involved, or is it based purely on non-covalent bonds such as hydrogen bonds? Why is denaturation ...
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438 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 ...
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26 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. ...
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27 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) ...
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30 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 ...
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6 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 ...
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36 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 ...
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20 views

about diffusion equation [closed]

consider the heat equation $u_t=a(t)u_{xx}+f(x,t)$, $0<x<L$, $0<t<T$ subject to the initial condition $u(x,0)=g(x)$ and boundary conditions $u(1,t)=0,$ $u_x(0,t)+hu(0,t)=0$ where ...
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1answer
21 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 ...
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3answers
31k 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 ...
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1answer
32 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 ...
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11 views

Related to mood disorders and research? [closed]

I would like to get a direction on research topics related to mood disorders. Any suggestions on important papers related to it will be very helpful. Also I would like to know the current trends in ...
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3answers
129 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?
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23 views

3 main classes of proteins that need to be sorted before leaving the golgi? [closed]

What are the three main classes of proteins with different destinations that must be separated before they leave the trans Golgi network? I'm quite sure one has to be enzymes but I'm not sure about ...
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1answer
93 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 ...
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17 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 ...
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30 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, ...
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71 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 ...
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1answer
63 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 ...
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1answer
155 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 ...
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54 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 ...
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119 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 ...
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40 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 ...
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43 views

Poly Unsaturated Fatty Acid

PUFAs spontaneously oxidize, speed up the process of glycation, since too much glucose and they also decrease mitochondrial respiration - more oxygen and CO₂, less lactate and PUFA also promote ...
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2answers
47 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, ...
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1k 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 ...
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37 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. ...
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172 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 ...
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22 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
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1answer
32 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 ...
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1answer
29 views

PSI-BLAST website algorithm parameters

http://blast.ncbi.nlm.nih.gov/Blast.cgi In this website, when I want to apply the psi-blast algorithm on a sequence, under the section of algorithm parameters , what does PSI-BLAST threshold mean? ...
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450 views

Amino acid characteristics that determine their chemical properties?

What chemical aspect of amino acids results in their having different properties such that the chemical and physical properties of polypeptides vary with both amino acid content and amino acid order? ...
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15 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?
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22 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
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2answers
277 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.
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16 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 : ...
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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 ...
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4answers
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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 ...
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38 views

What are the ways to test for protein in the canine urine?

I know that one way is to use the reagent sticks and the refractometer, but this is inaccurate. Is protein distinguishable when using a microscope? Is it time sensitive(i.e. have to test it right ...
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66 views

Where do the electrons and protons formed from biological reactions go?

In a reaction like disulphide bond formation protons and electrons are released. These particles are presumably damaging in high levels. What systems are in place to prevent a build up of electrons ...
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24 views

recombinant peptide MHC complex

What is recombinant peptide-MHC complex??? Recombinant DNA means "to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in biological ...
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1answer
36 views

How can I determine the purity of cells isolated from rat brains if I cannot use FACS, Immunohistochemistry or SEM anaysis?

Please help. I know how to isolate the different cells (astrocytes, other glial cells, neurons and synaptosomes) from brain tissue using a Ficoll-based separation but how do I determine the purity of ...
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Immunomic Microarray

"One can measure two or more signals simultaneously determined by a single feature, i.e., epitope in immunomic microarray DNA microarrays measure one response value for each gene per sample; that ...
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What is the physiological difference between cortisone and cortisol?

There is only hydrogen bond different. Cortisol is synthesized by our body, while cortisone is given to the patient. Why you cannot give cortisol directly to the patient? I think the reason is ...