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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56 views

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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2answers
98 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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0answers
40 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, sulfide-reducing bacteria (SRB) are more abundant, in high-salt-fed group compared to the ...
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1answer
143 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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29 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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1answer
35 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
38 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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2answers
111 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 = H+...
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81 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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1answer
49 views

In flowering plants food is transported in which form? [closed]

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
1k 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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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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1answer
34 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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0answers
41 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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1answer
17 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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1answer
55 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
21 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 ...
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0answers
4 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 ...
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1answer
31 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
58 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 ...
6
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3answers
121 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 ...
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2answers
82 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 ...
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0answers
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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22 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 ...
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1answer
27 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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0answers
37 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 ...
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19 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, ...
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1answer
27 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 ...
5
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1answer
69 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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0answers
21 views

Does alpha-amylase from different species have different *optimal* conditions?

Do the optimal conditions for the enzyme isoforms differ between species? Specifically, do the optimal pH and temperature for alpha-amylase differ for that enzyme produced by B. lichiniformis and A. ...
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2answers
62 views

Grouping OMIM disease codes

I have ~100 sets of genes, and each set includes between 2 and 70 genes. I'd like to perform an enrichment analysis on each of these sets to test if they're enriched for OMIM disease labels. However, ...
5
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1answer
81 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 ...
14
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1answer
954 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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2answers
276 views

Starch vs Cellulose. What are the differences between Alpha and Beta glucose ring structure in them?

I'm studying "Campbell Biology, 10th Edition" and in chapter 5 page 71 there's a statement I can't understand. according to book: In starch, all the glucose monomers are in the α configuration. ...
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1answer
77 views

Goodwin oscillator explained

Hello I have been reading papers about the Goodwin oscillator and I found that the equations are kind of tricky. Specially the part of the hill coefficient. In his paper "An entrainment model for ...
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1answer
54 views

Reason Non linear Lineweaver–Burk plot [closed]

V vs S plot looks like hyperbolic but 1/V vs 1/S plot is not linear at all. Looks like some kind of exponential growth. What can be the reason?
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2answers
335 views

Why does haemoglobin's affinity to oxygen decrease at high altitudes?

My class 12 NCERT book says, Pg 226 The body compensates low oxygen availability by increasing red blood cell production, decreasing the binding affinity of haemoglobin and by increasing breathing ...
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1answer
47 views

What happens during the fermentation process of the eco-enzyme?

introduction about the eco-enzyme I have tried to make several ones at home, no matter what I am using, lemon or pineapple peels with brown or white sugar, the final products all show the similar ...
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1answer
107 views

What is ATP and why is it said to be a source of energy? [closed]

Is ATP a molecule or a kind of energy. When I studied the active transport, it's said the ATP would release energy to change the carrier protein shape. So confused. Thanks for your help.
6
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1answer
101 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?
3
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1answer
106 views

What is the difference between the mitotic spindle and microtubules?

In mitosis, I understand that the centromeres line up on the spindle. I also know that the centrioles form microtubles between the centromeres during mitosis in the metaphase. But, are microtubles ...
6
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1answer
53 views

Is there a difference in cytoplasmic pH between prokaryotes and eukaryotes?

The cytosolic pH in human cells is around 7.4, but fluctuates as the cell is replicating. Prokaryotes and eukaryotes are vastly different in many ways. One thing they share is cytoplasm. Is there any ...
4
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2answers
74 views

What is the meaning of the “d(…)2” notation when writing a DNA sequence?

When the sequence of a DNA oligo is written as d(CGCTAGCG)2 what is the meaning of the d(...)2? Why would it not simply be ...
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0answers
24 views

If chylomicrons can not get into the capillaries, how do they supply to tissues?

The transport of chylomicrons is into the lacteals mainly because they are too big to get into the capillaries and yet they later supply triglycerides in the extra hepatic tissue by traversing in the ...
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0answers
30 views

Why are amides transported via xylem vessels? Why not phloem?

There is a statement in my textbook: "since amides contain more nitrogen than amino acids, they are transported to other parts of plants via xylem vessels" I wanted to know why the book ...
2
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1answer
50 views

Why does protein kinase C activated by different means have different effects?

I could be way off base but I think I remember learning that Protein Kinase C has some effects when activated by one pathway and other effects when activated by another. How does this happen? Is it ...
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0answers
29 views

Can aptamers be used to identify the terminal amino acid residue of a peptide?

Suppose there were DNA or RNA aptamers that bind specifically to a certain terminal amino acid residue. Let's name it aaSA (amino acid specific aptamer). For example, the aptamer binding to terminal ...
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0answers
119 views

Whole gene sequence analysis to determine source infection [closed]

Is it possible to use whole gene sequence analysis to distinguish between a common source infection and a person-person disease transmission?
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2answers
74 views

Can bacteria metabolize fatty acids for fuel?

I'm not a microbiologist, but rather a physiologist curious about microbial metabolism. Much like humans bacteria can utilize glucose, but when it comes to long chain, medium chain, or short chain ...
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89 views

Why do animals have more heavy nitrogen and carbon than plants?

There are two stable Isotopes of nitrogen N14 and N15. The ratio of 15N/14N tends to increase with trophic level, such that herbivores have higher nitrogen isotope values than plants, and ...