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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What is an effective method for putting on blue rubber butyl stoppers?

They look like this. We have to do a lot of gas sampling and these are really difficult to assemble. I've been scouring the internet for advice but there are none. Do you have experience with ...
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2answers
506 views

Why is oxygen needed for the electron transfer phosphorylation?

I understand that oxygen is the acceptor of electrons and hydrogen ions during the electron transfer phosphorylation, the last step off the ATP-producing aerobic respiration. But why? Aren't there ...
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41 views

Concentration dependent cellular processes

Are there any famous biological processes that depend strongly on a chemical concentration reaching a particular value, like some sort of switch? E.g. if concentration of chemical x reaches ...
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1answer
56 views

Why do oncogenes show genetic dominance?

As we know that tumor suppressor gene causes cancer only when both the alleles are recessive in nature.But in case of oncogenes if only one allele is dominant it can cause cancer.Why in case of ...
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1answer
46 views

Mechanism of DNA gyrase inhibitor

Why DNA gyrase inhibitor, such as Nalidixic acid and Norfloxacin, do not stop gyrase from cutting DNA helix but only prevent them from decatenation replicating DNA?
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2answers
102 views

Bohr effect in respiration

Would I be correct in saying that the Bohr effect is ONLY related to the concentration of [H+] in the tissues. Obviously the concentration of carbon-dioxide can contribute to this concentration by ...
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1answer
75 views

naturally occuring fatty acids

The double bonds in naturally occurring fatty acids present in our body are in cis configuration while the enzymes for beta oxidation can act on trans double bond. Then what will be the significance ...
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89 views

What organism most efficiently converts a given quantity of mass into heat?

Question I am trying to answer: In the popular film The Matrix, heat given off by humans is harvested as an energy source. I wondered, if this were possible, would humans be a good organism to ...
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38 views

About molecules and their shape

When a molecule is being used in some biochemical process it has a certain 3-d structure. Is this maintained throughout it's usage or can one specific molecule change it's 3-d shape while it is being ...
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4answers
103 views

Why is too much glucose harmful?

I learned the citric acid cycle in biotechnology school and how cells work; about ADP and ATP and how the Cellular respiration (C6H12O6 + 6O2 -> 6CO2+6H2O) works. I am interested in understanding why ...
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47 views

Can non-carbonated energy drinks boost alcohol intoxication?

I just read news article about banning caffeine in alcohol drinks and about that energy drinks increase the urge to drink alcohol. Energy drinks cause sugar intoxication - answer about it here ...
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39 views

bacterial cell wall degradation in humans

can human degrade the D-amino acid present in bacterial cell wall, I'm confused about it i have read somewhere that human can do so.If yes than why we need antibiotic to kill bacteria???If it is not ...
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80 views

Scale up of Bacterial growth from 250mL to 1-5L?

I am currently growing up a specific strain of E.Coli with a knockout in 40mL of growth medium (LB) in a 250mL shaker flask... My ultimate goal is to scale up this process to a 1-5L large scale setup ...
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42 views

Isoprene and Acrolein emissions of wood burning, insect burning and smoldering tobacco cigarette [closed]

I'd like to identify what makes a fume more or less toxic, above all those from commonly smoked organic stuff: tobacco, cannabis, comparatively to less common ones. For that, we can focus on 2 gas ...
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0answers
210 views

What chemical form of vitamin A is in chicken's egg yolk?

After doing some existing background research I am confused as to exactly what, in an unfertilised chicken egg's yolk, offers what we intake as 'Vitamin A' upon eating it. Plants typically produce ...
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3answers
135 views

More entropy: Atom or Macromolecule? [closed]

A question that appeared on my last exam was : Which of the following has greater entropy A) An atom B) A macromolecule The question doesn't specify anything else(i.e. type/size of atom or ...
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91 views

Why doesn't honey spoil quickly? [duplicate]

Why is it that honey can last for decades and not spoil like other foods? Is there any chemical in honey which gives rise to this amazing feat?
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2answers
293 views

Effect of steroid hormone on specific cells?

As steroid hormones can pass through the plasma membrane by simple diffusion because they are lipid derived hormones, it means that they are capable of passing through every cell of our body, BUT why ...
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1answer
86 views

Mesoporous silica particles as anti cancer drug delivery method

If this question is a little off topic for Biology, I'm sorry. I've recently read a lot about mesoporous silica nanoparticles as a promising drug delivery method. The huge range of customizability of ...
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1answer
104 views

Question about Monofunctional glycosylases

I am learning about Base excision repair mechanism. I understand the main idea how glycosylases are working, but I am trying to understand this with much more details. I found a paper where they are ...
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1answer
79 views

How to recognize a conserved motifs of the protein

I would like ensure that my reasoning is correct. Assuming that I know the aminoacids sequence of the protein of interest. I can't say anything about the structure looking only at the aminoacids ...
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2answers
202 views

Significance of synthesis of D-glucose in plants..?

why plants can only synthesize D-glucose why not L-glucose along with D glucose. I know it very well that plants have only enzymes which can synthesize D-glucose but Why not they have enzymes which ...
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1answer
59 views

Formation of peptide bond..?

Proteins peptide bond is made by condensation process in which a molecule of water is released and according to this process it is not favorable in water systems than how peptide bond is formed by ...
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1answer
181 views

which signalling pathway is involved in cancer?

Columnar epithelial cells from the colonic mucosa are studied to identify abnormalities in cell signaling pathways. Abnormal epithelial cells from colonic adenocarcinoma are shown to have a mutation ...
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212 views

Effect of testosterone hormone on cell signalling and behaviour?

A steroid, testosterone was injected in female body which led to development of secondary sexual characters but these characters were not developed over night (Response was very slow). What could be ...
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667 views

Why does Hunger lead to the aggressive behavior?

I have observed that frequently when people are hungry; they tend to get angry more easily on pointless issues. Does this mean that our fight or flight response is more active when a person is hungry? ...
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4answers
200 views

Specificity of Protein Kinases in Signaling Pathways..?

In most of the signaling pathways the activated receptor when activates Protein Kinase through the action of secondary messenger, then these protein kinases almost always phosphorylate on the specific ...
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2k views

Essential amino acid codons

Essential amino acids also have codons.Still they are needed by humans through diet?Will those codons do synthesize amino acids for some other purposes in humans or not?If so, what is the purpose?e.g? ...
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23 views

Primers on Dystonia

Where can I get a good biochemical overview of dystonia? I will be working in a research lab that focuses on dystonia and I would like to not be clueless.
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37 views

Is the sense for salt depending on the electrolyte level in our body?

I often noticed, after (heavy) physical activity like cycling, running, swimming or working an isotonic drink (to recover the electrolyte level) tastes less "salty" compared to when drinking it before ...
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1answer
635 views

Equation for accurate prediction of PCR yield

It is a cliche of freshman biology labs to point out that "every cycle of PCR doubles the DNA, so the yield will be $2^{cycles}$ times the template amount". However, if this were true, 1 ng of ...
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108 views

alpha tubulin molecular weight problem

Is there any academic reference that shows α-tubulin is around 50-55 kDa? The only thing I found is some data sheets from companies. I need the real reference.
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149 views

How does guanidium denature DNA?

Guanidium salts like (G-isothiocyanate) disrupt the hydrophobic interactions inside a protein or nucleic acid and denature it. What happens when hydrophobic interactions in DNA are broken? (I don't ...
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1answer
168 views

How do a particular arrangement of atoms become self aware? [closed]

At the simplest level, we're all just atoms, animals, plants and humans alike. But what I don't understand, is how a particular arrangement of atoms such as us can become self aware, and be able to ...
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58 views

What are the ecological effects of moderately high and prolonged concentrations of nitrogen deposition on an ecosystem?

There are many sources of nitrogen which eventually get deposited out of the atmosphere and onto the land/surface. Typically higher levels of nitrogen compounds are emitted near urban and roadway ...
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1answer
285 views

Anaerobic respiration choice in E. coli

Under anaerobic conditions E. coli has two options to generate ATP: fermentation (substrate-level phosphorylation), and respiration (proton gradient, chemisomotic phosphorylation). Which is favored? ...
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1k views

How much vanilla will kill a person?

I received a gift that is a jug of Pure Mexican Vanilla. Having never dealt with large quantities of vanilla, it made me curious as to what would happen if a person had too much vanilla. I understand ...
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2answers
2k views

Diffusion of Hypotonic solution into solution with glucose and starch

Cell walls are selectively permeable to ions and organic molecules. Sometimes the selectivity is passive and a reflection of the physical laws governing diffusion. We can do simple experiments that ...
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1answer
41 views

Feedback affecting myocyte metabolism in humans

I understand that there are several reserves available to muscle that can be tapped for ATP, and that each reserve is being used to some degree at all times. Are these reaction rates purely due to ...
2
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1answer
56 views

What is inside IDL (intermediate density lipoproteïn)?

I am studying about the endogene lipidcycle in the human body and I know that VLDL (very low density lipoproteïn) is made in the liver and that it contains triglycerides and cholesterol from your food ...
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1answer
111 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
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1answer
57 views

Trimming of tRNA precursors

From Molecular Biology of the Cell (4th edition) by Bruce Alberts et al. (Chp 6, Pg 338) : Both bacterial and eucaryotic tRNAs are typically synthesized as larger precursor tRNAs, and these are ...
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1answer
181 views

Is fluoride toxic, and how worried should I be about it?

A recent flurry of "fluoride is bad!" posts are appearing on my social network news feeds. Usually I can simply ignore them after a brief look, but this one, stemming from a recent article in The ...
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49 views

Vitamin D oral intake, transportation and absorption

Several factors affecting vitamin D and its active form absorption and storage acidity of stomach (not significant effect) cytopathic effects of viruses cytopathic effects of bacteria where the ...
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1answer
60 views

H O N C alternatives for organic life?

Most organic structures built from hydrogen, oxygen, nitrogen and carbon. They are represent 1-,2-,3-,4- bond relations (chemical valence) which allow to build variety of chain structures. Are there ...
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1answer
468 views

What's the difference between Ki and IC50?

I have just read this post at researchgate: "How to calculate experimental binding free energy from the IC50 value" I am not be very sure about what the difference is between Ki and IC50. Could ...
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1answer
152 views

Transverse diffusion of lipids in red blood cells

The membrane of a human erythrocyte has polarity: Phosphatidylethanolamine and phosphatidylserine are predominantly on the inner side. Phosphatidylcholine and sphingomyelin are predominantly on the ...
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2answers
303 views

Signaling through G protein Coupled Receptors?

There are two different cell lines but we do not know that these cell lines have Gs or Gi proteins, associated with their G-protein coupled receptors. If we wants to know about this. Can we design a ...
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0answers
27 views

Is life in a supercritical fluid possible?

Someone claimed that the dinosaurs could only live because back then athmospheric density was around 650 kg/m³, providing some buyoncy, this claim is checked on Skeptics SE. The claim itself is beside ...
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1answer
75 views

Why is brown fat brown?

I read in Tortora and Derrickson Anatomy and Physiology that : Another type, called brown adipose tissue obtains its darker color from a very rich blood supply , along with numerous pigmented ...