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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Which mammals cannot synthesize taurine?

It is fairly common knowledge that domesticated cats cannot synthesize the compound taurine. Other mammals seem to be able to synthesize taurine from cysteine [source]. Are there other mammals that ...
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1answer
50 views

Difference between the P4 and P5 subtypes of P-type ATPases in plants

In plants there are various kinds of P-type ATPases. What is difference between P4-ATPase and P5-ATPase?
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2answers
83 views

What makes something food?

From my (limited) understanding, animals get energy from food by breaking chemical bonds between molecules. There's a lot of water here [citation needed], so it seems like natural selection would ...
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7 views

Cell Lines in Cancer Biology [on hold]

Where could I find information regarding cell lines such as A549, MDA-MB 468, MCF-7, Hela etc. with respect to their origin, usage, mechanism of action, specific receptors, advantages and ...
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14 views

Wrong amount of Glycerol for medium

I need to make agar plates, usually I add 2.5 ml of Glycerol per bottle but I am not sure if I made a mistake and I added 0.5 ml to one bottle and 3 ml to the other one.Would I see diferences if I ...
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1answer
19 views

Link between NaCl and sulfide reducing bacteria

Could there be any link between the consumption of NaCl and sulfide-reducing bacteria? In my study on mice, I can see, by adding more NaCl to mice diet, less (or to be more accurate, zero) ...
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6k views

How does a plant grow before photosynthesis is possible?

During photosynthesis, a plant translates CO2, water and light into O2. I assume the carbon C is further used for the growing process. I wonder how the plant grows before the time where photosynthesis ...
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137 views

Does the use of RNA as a primer affect the accuracy of DNA replication in E.coli?

DNA polymerases have proof-reading ability, but RNA polymerase does not. Does the use of RNA as a primer affect the accuracy of DNA replication in E.coli? Explain
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94 views

Animals that live in polar environments spend much of their time with their lower limbs buried in snow. [closed]

Animals that live in polar environments spend much of their time with their lower limbs buried in snow. What differences in lipid composition might you expect to see if you compared cell membranes of ...
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1answer
22 views

Enzyme kinetics: recommended literature to grasp the concepts better

I have had a few biochemistry courses, but I still feel confused and a bit scared each time they try to explain and apply enzyme kinetics or even chemometrics in different situation during class. On ...
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58 views

What Chemical Trigger Causes Ectomycorrhiza To Change From Asexual To Sexual?

I want to know the trigger behind the change of asexual to sexual ectomycorrhiza when symbiosis with a tree root is formed. As ectomycorrhiza attaches itself to a root, it forms a relationship wherein ...
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94 views

RNA primer affect the accuracy of DNA replication in E.coli [closed]

DNA polymerases have proof-reading ability, but RNA polymerase does not. Does the use of RNA as a primer affect the accuracy of DNA replication in E.coli? Explain
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2answers
57 views

Can photosynthesis take place if the plant is kept in ice cold water or not?

Can photosynthesis take place in a plant even if the plant is kept in ice cold water? I have googled this question, but so far have not found a satisfactory answer.
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48 views

Light and Dark Reaction of photosynthesis?

I'm having a hard time understanding light and dark reactions because all the sites I've gone through provide different equations. Some say photolysis is H20 = H+ + O2 while some present it as H20 = ...
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1answer
28 views

meaning of arrows in a 3D biomolecule representation

I would like to know what those arrows and also thin wires between them in this cd4 biomolecule's 3d representation mean. Thanks in advance.
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1answer
23 views

Find the concentration of free receptors in a solution of 90% free ligand and 10% receptor-ligand complex, knowing only the value of kD

I could use some guidance on how to utilise the equation for the disassociation constant kD to find the concentration of free receptors [R] in a solution containing 90% free ligand [L], and 10% bound ...
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1answer
31 views

In flowering plants food is transported in which form?

In flowering plants food is transported in which form? I searched on google and found that it is sucrose. Why not glucose/fructose/starch?
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1answer
87 views

How many protons are pumped out per pair of electrons from NADH in oxidative phosphorylation?

I have searched the web and found that 10 protons are suppose to get pumped out during the electron cycle, but i'm a bit confused. I'm trying to count, for every complex(1/3/4), the number of protons ...
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1answer
105 views

How do lipid-soluble substances diffuse through the cell membrane?

It’s said that water-soluble substances can diffuse through cell membrane with less ease than lipid-soluble substances because the former encounters impedance in the hydrophobic region of the ...
3
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1answer
70 views

How does beta branching stop alpha helices from forming?

I am told that beta branching interferes with alpha helix formation. Problem is that I don't see how beta branching has anything to do with alpha-helix formation. Beta-branches are on the outside of ...
4
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1answer
80 views

Synthesis of Fatty Acids Longer than 16 Carbons

I understand that the human body when performing Fatty Acid Synthesis can synthesize only until C16 (palmitate). However the ER has desaturases and elongases. I know that desaturases are used to add ...
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0answers
56 views

RAGE Oligomerization and Signalling Mechanism

I am looking to understand the mechanism of how the advanced glycation end products, s100 proteins and B-amyloids interact through oligomerization with the RAGE molecule (AGE receptor). I would also ...
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1answer
996 views

Why is chlorophyll green? Isn't there a more energetically favorable color? [duplicate]

Chlorophyll being green means it absorbs light in the red and blue area of the spectrum. Isn't this the high and low energy light? Wouldn't plants get more energy if they absorbed light in the green ...
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1answer
32 views

Can one talk about deacetylation of a promoter rather than associated histone?

I am confused on a detail in a paper I am reading and am not sure whether I am misunderstanding the wording or misunderstanding the concept. I am including the whole abstract of this paper for ...
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28 views

Do ion channels block at these temperatures?

I found this paper and it says nerve axons cold block at temperatures near 0C. http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.1968.sp008656/pdf Does this mean ion channels also block (due to ...
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36 views

What do sharks not like the smell of?

I was reading about the sharks strong sense of smell ( Shark senses - @EnhancedLearning.com ) and wondered if any research has been done into what they don't like the smell of? Is there any material ...
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3answers
102 views

Function of the alpha subunit in mitochondrial ATP-synthase?

Within the catalytic core of mitochondrial ATP-synthase there are two different types of subunits; $\alpha$ and $\beta$. From what I have read, the catalytic sites occur only in the $\beta$ subunit so ...
14
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1answer
947 views

I don't want to know what bacteria is called but if the bacteria from unborn babies have benifits on health? [duplicate]

This question is not the same as the duplicate. I was told that when babies are born they are born with bacteria in their stomach. When a child takes antibiotics are there unique bacteria destroyed ...
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1answer
35 views

Optimizing Gel Electrophoresis: Ampere, Volts and Buffer concentrations

I am a master student in biochemistry, and I have used gel electrophoresis many times before. What I want to know is how one should adjust the mA (mAmpere) compared to the voltage and the buffer one ...
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0answers
50 views

Disease-Associations For Protein Analysis? [closed]

I would like to get access to any protein database of disease-associations which I could use home with biomechanical signals in different systems. A similar software to what I am looking for is the ...
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1answer
16 views

How is receptor production (recycling) regulated?

My understanding of receptor downregulation is that when activated, a receptor then gets absorbed into its cell, as shown in this weird video. It then gets either recycled or degraded. Tolerance ...
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2answers
70 views

Use of sunlight in biological processes

Sunlight is used by green plants in photosynthesis, but it is also used by animals in the synthesis of Vitamin D. Are there any similarities between the two processes and how is the light energy ...
5
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1answer
143 views

enzymes that stabilize DNA loops

As a follow-up of a previous question, I would like to know what enzymes or protein complexes have been used to manipulate DNA samples into stabilizing DNA loops. I have read that cohesin is one of ...
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1answer
56 views

How do disulphide bonds in hair cause curling?

I understand that the asymmetrical distribution of disulphide bonds in hair cause curling, but do not completely understand why this causes an inherent curl on the macroscopic level, for several ...
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17 views

How much yogurt would one have to consume to have a noticeable effect on neurotransmitters [closed]

I read several recent articles that proposed a link between bacteria in our gut and neurotransmitters in our brain. For instance http://www.ncbi.nlm.nih.gov/m/pubmed/24997036/ I am curious how much ...
14
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1answer
262 views

Why do specifically bananas go brown quicker in the fridge?

Perhaps the title should be: Why don't all fruits containing phenol residues go brown quickly when left in the fridge? Bananas go brown over time because of the oxidation of phenol residues. ...
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2 views

Plant symbiosis, alternative regulation pathways to AON and miRNA399?

I am currently studying systemic repression of both arbuscular mycorrhizae and nitrogen fixing bacteria in legumes. I know of the AON pathway (which works through CLE and NARK). I also know of ...
5
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1answer
136 views

How do omega-3 fatty acids reduce cholesterol at the molecular level?

I have heard that omega-3 fatty acids found in fish are a good way to prevent/reduce cholesterol problems. My question is how do omega-3 fatty acids do that: what are they doing on a chemical level ...
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1answer
24 views

Is water vapour a product of fossil fuel oxidation?

In textbooks, while water vapour and carbon dioxide are said to be the greenhouses gases which are most abundant in the atmosphere, when a table is given showing the top greenhouse gases emitted by ...
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0answers
20 views

Where do class 2 preservatives end up after digestion?

Do anybody know what happens to class 2 preservatives in general after they are digested - i.e details like weather they are absorbed into blood as simplest elements or excreted out or assimilated to ...
5
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1answer
72 views

Can difference in the expression potential of alleles lead to dominance?

Several hour ago I was in thoughts what allele dominance really means on molecular level. As we know from basic genetics, if the organism had Aa type of some gene ...
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13 views

Amount of Na+ needed to be transfered in order to depolarize the membrane?

I found out that the number of $Na^+$ ions that is needed to be transfered across the membrane to make it depolarized is a small number. In what way its proved? (Goldman equation maybe?)
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1answer
23 views

Hydrophobic proteins in the body?

I know that we can get hydrophobic amino acids, but are there any proteins in the body whose surface is hydrophobic? If so what is their typical function and where can they typically be found and if ...
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2answers
114 views

Extending a small fragment of DNA

Is there a way to extend a small fragment of DNA, say 150 bp, by making copies of itself and attaching each copy of that small fragment to the end of that 150 bp sequence? For example, I want a 1 ...
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0answers
31 views

When touch and pain are caused by heat/cold or pressure how are the nerve cells triggered?

I suppose that when your skin is smoothly touched by any cold/heat or pressure we feel that because our AB cells notice this due to a kind of change in the nerve cell. But when you touch something ...
3
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1answer
133 views

Why does Citric Acid occur in Citrus fruits?

Why is there so much citric acid in citrus fruits? And how did it evolve i.e. what did it come from? Is it a by-product of the ripening process? Why have citrus fruit evolved a particularly high ...
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0answers
17 views

Cellular demand for antioxidants

Antioxidants such as ascorbate and glutathione serve to inactivate radicals and counteract spontaneous oxidation reactions, such as unwanted disulfide bonds in proteins. These systems are cycles, ...
6
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1answer
74 views

What determines whether a substance can diffuse across the blood-brain-barrier?

What determines whether a chemical substance is able to cross the blood-brain-barrier via passive, transmembrane diffusion? What structurally differentiates these chemicals?
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47 views

How are ions 'pumped' across a membrane during electron transport?

A number of sites (including this one) that provide descriptions of photosynthesis state that high energy electrons 'pump' ions across a membrane. What is the actual 'pumping' mechanism? I've looked ...
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23 views

Is H antigen considered as an agglutinogen?

A and B antigens which have the potential to cause agglutination in certain cases are called agglutinogens. But, as far as I know, H antigen cannot give rise to agglutination. So can it be said that H ...