The study of chemistry within the scope of biology: the compounds that occur and the reactions involving them in living organisms.

learn more… | top users | synonyms

11
votes
1answer
308 views

What is the transmembrane 'Positive-Inside Rule' nowadays? Has the definition changed over time?

First definition. Two publications by von Heijne in 1989 and 1992 coined the 'Positive-Inside rule' and showed it's practical value in topology prediction of transmembrane helices. It was clearly ...
0
votes
0answers
7 views

Bence-Jones proteins in urine on heat

The preliminary test for proteinuria is precipitation/turbidity on heat due to denaturation. This turbidity should not disappear when 10% acetic acid is added - to differentiate from phosphates. ...
6
votes
2answers
169 views

Are Gram negative bacteria classified as such because of their negative membrane potential?

Does the membrane potential usually quoted for Gram negative bacteria (e.g., E. coli) refer to the potential across both membranes? - If yes, then does the potential fall more over the inner or outer ...
0
votes
0answers
15 views

nitrogen isotopes in plants

From what I know it is possible to assess an animals diet based on stable isotopes from carbon. Does anyone know if its possible, in a similar way, to derive animal community based on N-deposits which ...
1
vote
1answer
55 views

Which organisms have their cell wall made of polysaccharides and amino acids?

I came across a question which somewhat goes like In which of the following kingdom, most of the members have a cell wall made of polysaccharide and amino acids ? - Monera or Fungi. To me it ...
8
votes
1answer
496 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 ...
1
vote
1answer
30 views

Can you replace glucose with glycerol in cell media?

In order to feed an animal cell in process called Respiration, can I replace Glucose with Glycerol? The Equation bellow: Glycerol + Oxygen -> Water + Carbon Oxide
-3
votes
0answers
50 views

Why/How does matter on earth exist in all 3 states of matter? [on hold]

Why does most matter on earth exist only in the form of liquid/solid/gaseous? I know that helium is an exception to this rule, and that all atoms itself will always be the same, whatever state it is ...
0
votes
1answer
32 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 ...
1
vote
2answers
442 views

Can excessive carbonated drink consumption lead to elevated red blood cell levels?

I've recently had a blood test and the results displayed elevated levels of erythrocytes as well as hemoglobin. (As a result my hematocrit levels were also above average) At my workplace there is a ...
0
votes
1answer
36 views

Diabetes Mellitus and renal failure?

I have studied that Diabetes Mellitus leads to kidney failure and that this is because of the damage to the blood vessels (especially the blood vessels in the kidney) due to high levels of blood ...
2
votes
2answers
122 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 ...
1
vote
1answer
24 views

Is there a difference between “Alpha Helix” and “Alpha subunit”?

In my biochemistry textbook the terms alpha helix and alpha subunit are both used. Are these two terms synonymous? For instance, hemoglobin has an alpha and beta subunit, are these the same thing as ...
8
votes
1answer
6k 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 ...
-1
votes
0answers
18 views

peritoneal dialysis Vs Hemodialysis?

Their are basically two types of dialysis: 1.peritoneal dialysis 2.hemodialysis, My Question is Why the peritoneal dialysis needs to be carried out on everyday BUT hemodialysis is carried out on only ...
1
vote
1answer
40 views

Is there nothing such as NADPH2? [duplicate]

I have gone through various sites and some say there is NADPH2 and some say there is no NADPH2 there's only NADP+ ...WHich is the correct view....Please dont mark this answer as duplicates since I ...
5
votes
1answer
68 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 ...
1
vote
1answer
48 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 ...
2
votes
1answer
51 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?
-1
votes
2answers
86 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 ...
-1
votes
0answers
10 views

Cell Lines in Cancer Biology [closed]

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 ...
14
votes
2answers
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 ...
0
votes
1answer
140 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
0
votes
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 ...
3
votes
0answers
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 ...
0
votes
2answers
62 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.
3
votes
2answers
56 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 = ...
1
vote
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.
0
votes
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 ...
1
vote
1answer
34 views

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

In flowering plants food is transported in which form? I searched on google and found that it is sucrose. Why not glucose/fructose/starch?
3
votes
1answer
92 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 ...
3
votes
1answer
109 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
votes
1answer
71 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
votes
1answer
81 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 ...
2
votes
0answers
57 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 ...
9
votes
1answer
999 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 ...
3
votes
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 ...
0
votes
0answers
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 ...
1
vote
0answers
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 ...
6
votes
3answers
103 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
votes
1answer
950 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 ...
2
votes
1answer
37 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 ...
0
votes
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 ...
0
votes
2answers
72 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
votes
1answer
144 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 ...
6
votes
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 ...
1
vote
0answers
18 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
votes
1answer
264 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. ...
0
votes
0answers
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
votes
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 ...