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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1answer
70 views

Advocate for the pop-culture idea of withholding vaccination [closed]

While it is widely accepted that vaccination is preferable to not vaccinating, would anyone like to give a shot at providing evidence in favor of not vaccinating? Anything goes.
0
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0answers
25 views

enzyme extraction protocol for papain

I am trying to work on fab fragments by digesting whole IgG with papain but finding it difficult finding a protocol for extraction of papain. Can somebody help me with a simple protocol, if per chance ...
1
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0answers
18 views

Yew seed dormancy reduction

Yew seeds have very long dormancy when artificially planted. They are also adapted to passage through digestive systems of animals that eat/transport them. But could the dormancy be shorter (or the ...
0
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2answers
57 views

In what two ways is ATP used in coupled reactions?

I already have down "A coupled reaction is when leftover energy from a reaction fuels a reaction that needs more energy. ATP can break apart to transform into something new and use the energy created ...
4
votes
1answer
570 views

Is ATP Synthase a channel or an enzymatic protein?

Today in a biology lecture about plasma membranes and functions of proteins, we learned about channel and enzymatic proteins along other kinds of proteins. ATP synthase is considered an enzyme that ...
2
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2answers
97 views

How to build a trimeric protein structure from monomeric PDB file?

Problem: I have a PDB file, with a monomer, but I would like to show the entire structure - which is trimeric - but I don't understand how to merge/build or combine the monomeric units to its full ...
1
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1answer
36 views

gene transformation from plant to plant - transgenic plant

I want to know if the expression of a transfered gene depends on source of the gene, if e.g.: 1] I isolate a gene from plant and transfered it to the same plant? 2] I isolate a gene that is highly ...
3
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1answer
64 views

How does heat generated by metabolism differ compared with heat generated through exercise?

I am from a mathematical background so I don't have much knowledge on biology. I'm building a mathematical model to predict heat generation with parameters of metabolic heat generation and exercise ...
3
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1answer
80 views

By what mechanism is NADP+ converted to NADPH in Photosystem I? [closed]

Here is my current understanding: $\mathrm{NADP^{+}}$ takes 2 electrons from Ferredoxin at the end of the electron transport chain to generate $\mathrm{NADP^{-}}$. An $\mathrm{H^{+}}$ ion in the ...
12
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1answer
289 views

How does paracetamol work?

Hinz et al. 2008 found that COX-2 may be inhibited by paracetamol, and this is attributed to it's analgesic and antipyretic properties. However there are other more recent claims from Andersson et ...
1
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1answer
29 views

How do you calculate the charge on a polypeptide chain with changing pH?

I understand the charge placement on the N & C-terminus and also the utilization of the R-side groups in the amino acids. For example, What is the overall charge for a chain Glu-Cys-Arg-Asp with ...
0
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0answers
11 views

Must one autoclave LB medium after it has been made? [closed]

Is it necessary to autoclave LB medium after it has been made?
2
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0answers
41 views

PCR that worked previously is now only showing primer dimers and a smear on gel

PCR amplification of a promoter sequence for gel extraction worked beautifully using Phusion HF enzyme with GC (higher error but less picky) buffer. However, DNA concentration from the gel extraction ...
2
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0answers
37 views

Nail polish toxicity studies?

Are there any well-founded studies that authoritatively demonstrate negative effects from the use of nail polish, particularly in children? I've been brought into the fray of a couple of folks who ...
1
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0answers
28 views

What proportion of ingested food is exhaled as CO2? [closed]

Obviously the answer varies according to type of food, and maybe the efficiency of gut flora, but approximately how much of the food we eat ends up as carbon dioxide, as opposed to faeces or urine? ...
1
vote
1answer
117 views

Why is there only 6 H2O produced in fatty acid synthesis (palmitate)

The equation for biosynthesis is 1 Acetyl-CoA + 7 Malonyl-CoA + 14 NADPH + 14H+ -> Palmitate + 7 CO2 + 14 NADP+ + 8HS-CoA + 6 H2O I really don't understand how there is only 6 H2O produced... and ...
7
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1answer
74 views

Experimental Analysis: What are possible reasons for this increase in N₂O production?

My professor wanted us to each conduct an experiment for class on something we thought would interesting. My experiment was very simple, but I'm not sure how to interpret my results. (Please note that ...
8
votes
1answer
61 views

How does membrane potential vary between intraceullar membranes and the cellular membrane?

Question Does each type of membrane have a different membrane potential? I'm especially interested in answers that can cite academic papers that have attempted to measure membrane potentials. ...
1
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3answers
40 views

importance of cDNA sequencing of a specific gene in different plants

i want to know what if i made a sequence of cDNA of a specific gene in different plants - what is the important from the sequence and can if found difference between plants , and can i use this ...
0
votes
0answers
18 views

Dispose off a medicinal substance

Is there a protocol or a set of guidelines to safely dispose off a batch of expired drugs (as a manufacturer)? I guess the process may vary for different drugs. My specific question regarding the safe ...
1
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0answers
52 views

How much energy would it cost to synthesize all cholesterol requirements de novo?

Imagine a scenario in which some person is unable to absorb any dietary cholesterol because of some intestinal mutation (for example). Thus, they have no cholesterol available from their diet for ...
0
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1answer
17 views

What causes fruit taste enhancement?

I'm not sure if this is a biology or chemistry question, maybe both? Some fruits, such as quince and quondong, taste of nothing when raw but have an extremely strong flavour when cooked. Why?
1
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1answer
51 views

Are there electron or proton receptors in our nose?

We can easily smell chlorine gas and its irritating odour, but we cannot smell oxygen gas. Do few protons and electrons make such difference to our olfactory receptors?
1
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2answers
71 views

Can RNases/DNases survive in strong acid/base solutions of around 10M?

This might be a very stupid question, but I am worried about RNase/DNase contamination of my samples. Since I use 37% HCl and 10M NaOH to pH almost all my buffers, this is a potential source. I have ...
2
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1answer
1k views

What is the role of glycine in the running buffer for SDS-polyacrylamide gel electrophoresis

We used pH6.8 in stacking and pH8.8 in resolving gel. In the class, the professor explained that the glycine change is like: ...
5
votes
1answer
122 views

How is adrenaline a ligand?

I keep reading that adrenaline is a ligand, however from what I understand a ligand is a molecule or ion which donates a pair of electrons to a central transition metal ion in a complex. How then is ...
14
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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. ...
1
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2answers
80 views

Getting PCR amplification at annealing higher than Tm!

I am amplifying a gene where in a gradient pcr i am getting amplification at an annealing temperature about 5 degrees (67) higher than Tm (62.5)? What is wrong here? Also, I am getting a very strong ...
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0answers
69 views

Giving life to a dead person [closed]

Could anyone please tell me whether we can conclude that no body of a dead human being can get life since all chemical reactions are irreversible in our human body?
0
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0answers
20 views

Will a metalloenzyme bind to its substrate in the absence of its metal ion cofactor?

A metalloenzyme is an enzyme using a specific metal ion as its cofactor. Their activity is dependent on this metal ion. For example, the T4 DNA ligase requires Mg2+ to ligate DNA strands; The ...
1
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0answers
23 views

What is the difference between cell, membrane and animal based assay?

I am reading a review about MRP1, discussing it's ability to extrude different compounds from cell interior. When describing the different experiments conducted to observe the MRP1's reaction to ...
2
votes
1answer
52 views

Chemosynthesis in Bacteria

The light reactions, if seen as a whole, are basically the oxidation of water to provide energy (ATP) to fuel the Calvin Cycle. The photons provide the activation energy for the same. How then can ...
0
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0answers
61 views

Why boiled starch is easy to digest?

I was reading about carbohydrate digestion and found information about starch digestion where the step wise digestion of starch starts with boiled starch and ends in isomaltose, maltose and alfa limit ...
3
votes
1answer
56 views

Do mitochondria digest fats?

I am a student and I'm currently using the IB biology Oxford textbook. A few weeks ago I had a test on biochemistry. I studied on my textbook and it stated the following: "Mitochondrion: (…) fat is ...
1
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0answers
29 views

Is pathlength correction vital to be included while quantifying protein

I am trying to quantify protein in serum/plasma samples. I have carried out biuret assay for my samples using microplate reader. While performing I encountered the doubt whether I should include ...
1
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2answers
243 views

Polysaccharide vs Macromolecule

I'm having trouble understanding the difference between Polysaccharide and Macromolecule. I know that polysaccharides are made of chains of monosaccharides. In addition, I know that ...
3
votes
1answer
110 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
45 views

Why would growth hormone (somatotropin) cause both lipid AND glucose release?

GH increases lipolysis (lipid breakdown) and the release of fatty acids from adipocytes into the blood. Fatty acids then can be used as energy sources to drive chemical reactions, including ...
0
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0answers
15 views

How much is the normal range of thiol/protein (mol/mol) concentration?

HSA(Human Serum Albumin) has just one free thiol group on Cys34. Using DTNB assay I obtained 0.4 thiol/protein (mol/mol) for this protein. I wonder if this value is a reliable number or not? does ...
2
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0answers
70 views

Proteases in the blood

I’m reading on hormones and the book talks about how peptide or amine hormones are easily broken down by proteases present in the blood plasma. This has led me to question the interactions between ...
7
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2answers
96 views

Permeability of Plasma Membrane

I’m having trouble grasping why small polar molecules can cross the hydrophobic region of the membrane and not ions. Won’t the polar molecules be attracted to the watery extracellular medium and not ...
2
votes
1answer
232 views

Why do mice have a higher metabolism?

Mice and other small animals have higher metabolic rate than humans. How does that happen on cellular level, if we look on one cell in the mouse body? What is it in this cell that will be ...
0
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0answers
38 views

Is it possible to measure in vivo enzyme kinetics?

I was wondering is there way in which we can measure enzyme kinetics in vivo specifically for enzymes acting on lipid substrates (where substrate is restricted to 2D membrane as oppose to freely ...
2
votes
1answer
69 views

All-trans-retinal being converted back to 11-cis-retinal or vitamin A

There are two pathways all-trans-retinal can take after detaching from the scotopsin: (1) it can convert back to 11-cis-retinal, or (2) it can convert to all-trans-retinol (form of vitamin A), which ...
1
vote
1answer
31 views

How is the enzyme glycogen synthase regulated?

How is the enzyme glycogen synthase regulated in regards to glycogen synthesis? I think I understand that phosphorylation decreases its activity (through glycogen synthase kinase?), but what role do ...
3
votes
1answer
83 views

What is the shortest mRNA the ribosome can read to produce a peptide?

This question came as a comment on a previous question regarding non-ribosomal peptide synthesis, and why Glutathione cannot be synthesized by the ribosome. In general, Glutathione has a "gamma" ...
5
votes
2answers
211 views

Why does depolarisation by high intracellular K+ trigger calcium channels opening?

I have learnt that in pancreatic beta cells, glucose being metabolised in the cell causes a high ATP level, which triggers ATP-dependent potassium channels to close. This means that potassium can't ...
5
votes
2answers
131 views

Non-ribosomal peptide synthesis: why Glutathione cannot be produced by the ribosome?

Case: I am writing a summary for a class in protein structure and function, and was asked to describe some different ways that peptides are synthesized (that does not involve the ribosome). I ...
1
vote
1answer
28 views

Why would a bacterial population show initial growth when it is in unfavorable growth conditions?

This figure shows the anaerobe E. faecalis grown in aerobic conditions, E. coli grown in restricted conditions that are not specified. Why do they show an increase in abundance initially? The black ...
2
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1answer
214 views

Anomalous base pairing of nucleotide tautomers

What tautomers base pair with what bases? I know that adenine pairs with thymine and guanine pairs with cytosine normally. My question is what does the imino form of adenine base pair with? Regular ...