Questions tagged [biochemistry]

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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How much energy is required to create Oxygen for one person per day? [closed]

There is an interesting question about about the energy we gain from Oxygen on StackExchange: How much energy we get from oxygen? But I want to ask another way around: How much energy would we need to ...
Pascal Klein's user avatar
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1 answer
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What is the difference between digesting sugar and carbohydrates?

To understand where I'm coming from, first some commonly distributed (mis?)conceptions: (Obviously to be taken with a big grain of salt because they are somewhat contradictory) Sugar is bad for your ...
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Which position do retro aldol reactions occur in (comparing glucose and fructose)?

Regarding glycolysis, my text states: What is the biochemical rationale for the isomerization of glucose 6-phosphate to fructose 6-phosphate and its subsequent phosphorylation to form fructose 1,6-...
TheAnonymous's user avatar
2 votes
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Use of ADP hydrolysis for driving energy-requiring processes?

The free energy of the hydrolysis of the β-γ phosphoanhydride bond of ATP is used to drive energy-requiring biological process such as chemical synthesis, movement, ion transport and production of ...
Archonic's user avatar
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Why does harper states that aldehyde dehydrogenase is a oxidase? Is it a misnomer then?

Oxidases are those which uses O2, but dehrydrogenases doesn’t? Then is my book wrong ? Is it a misnomer that aldehyde dehydrogenase is correctly a oxidase?
Dr Tenma's user avatar
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How to calculate the osmolality of Hepes solution?

Here is an excerpt from Kollmann et al. (2020, J. Physiol.): This ring was placed in a recording chamber continuously perfused with 37°C aerated Hepes solution containing (in mM) 136 NaCl, 10 glucose,...
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What is the optimal pO2 concentration for automated reactor batch mode EColi expression?

I am wondering what is the optimal pO2 level for an reactor based expression? All protocols I have found indicate for E.Coli pO2 levels just bigger 20%. So, I am wondering what is the optimal level? ...
raptorlane's user avatar
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Can you store 5% BSA, in TBST, in -20C?

I have stock solution of 5% BSA prepared in TBST I use to make primary antibody dilutions for western blot. I'll admit I just assumed -20C, with freezing and thawing as needed, was an acceptable means ...
Tom Murphy's user avatar
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Why don't membrane potentials violate the principle of electroneutrality?

The principle of electroneutrality states that the number of anions and cations in a solution must be the same, i.e., that there will be no charge excess in any side of the membrane separating two ...
TheAnonymous's user avatar
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3 answers
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Are stable isotopes ever used in pharmaceuticals?

Carbon has two stable isotopes, C-12 and C-13. Since they both have the same electronic structure they can both make up the same molecules, but presumably they may perform different functions in ...
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Does aerobic exercise increase the incidence of disease via free radicals?

Aerobic respiration produces ROS, atleast one of which (the hydroxyl radical) cannot be neutralized by any known antioxidant and is always damaging surrounding tissue. I know ROS plays a role in ...
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max % of oxygen not harmful for breathing?

Is breathing pure oxygen bad for you? Human blood is designed to capture oxygen and safely bind it to a molecule known as hemoglobin. However, if you breathe in a high concentration of oxygen, it will ...
Root's user avatar
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How to elute the protein that is bound to biotinylated RNA immobilized with streptavidin?

I would like to test the proteins that bind to biotinylated-RNA by mass spectrometry , I was using Dynabeads™ MyOne™ Streptavidin C1 (invitrogen) coupled with biotinylated-RNA,than mix these beads up ...
Fino's user avatar
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How come SSBPs in RPA don't bind primers?

I've started reading about the recombinase polymerase amplification (RPA). I'm learning that in RPA, recombinase enzyme binds to primers, then makes them anneal to the complementary target DNA strand, ...
Andrew Roots's user avatar
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How many pyrophosphate groups are released during dinucleotide formation?

I can't seem to fathom how a dinucleotide is formed. My textbook says that initially both nucleotides have 3 phosphate groups before the join but the formation releases only one pyrophosphate If ...
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Validating Generative Models for 3D Conformations of Inactive Dopamine Receptors in Protein Design

Considering a dataset comprising 3D conformations of Dopamine receptors in an inactive state, we aim to train a generative model capable of capturing the distribution of these receptors and generating ...
SilicoMar's user avatar
2 votes
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Can humans metabolize D-malate?

Only the L-isomer is produced naturally, while racemic mixtures are produced synthetically and used commercially as food additives and energy supplements. So what happens when we consume D-malate? ...
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Can a non-pure culture be used for reliable rapid phenotypic diagnostic tests?

Can a non-pure culture be used for reliable rapid phenotypic diagnostic tests (e.g. catalase, oxidase & gram stain)? "Slide Test Method Obtain a pure culture of the organism to be tested. ...
Freezing Soul's user avatar
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Why can mitochondria make only 34 molecules (rather than 61 molecules) of ATP ?

Why can mitochondria make only 34 molecules (not 61 molecules) of ATP from the energy obtained from the oxidation in the electron transfer system of NADH and FADH2 generated by oxidation of glucose in ...
Blue Various's user avatar
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How to measure cytochrome P450 activity in owls?

I hope you're all doing well. I'm currently working on a research project focused on owls and their exposure to anticoagulation rodenticides such as brodifacoum. As part of my study, I need to measure ...
mohammed 's user avatar
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Induction of IFN-beta in HEK293T

I'm trying to increase expression of a protein we're attempting to study, UBL7, supposedly unregulated by Type I Interferon and particularly IFN-beta. I've tried treating HEK293T cells (~60% ...
Tom Murphy's user avatar
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Where is the source of H+ in the matrix that will be pumped during the electron transfer system? Where does the OH generated at that time go?

In the electron transfer system, it has been mentioned in prior questions that complexes I, III, and IV are proton pumps and that these pumps pump protons from the matrix into the intermembrane space. ...
Blue Various's user avatar
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Fate of GTP produced in the TCA cycle

As someone already mentioned in one of the following questions, the TCA circuit generates GTP in addition to NADH and FADH2. The fate of NADH and FADH2 is clear: they are used to pump protons in the ...
Blue Various's user avatar
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Examples of mechanisms of metabolic trapping inside cells that create concentration gradient

I am looking for examples in biology in which a metabolite that can diffuse freely across a cell membrane (through passive diffusion), once inside, gets modified to a form that cannot diffuse back ...
Massimo Bilancioni's user avatar
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Effects of oxygenated water on bacteria

I was curious if any of you would happen to have any experience with this but any hypotheses regarding how this would turn out would be much appreciated. I’m wondering if water fully aerated with ...
Jaston's user avatar
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5 votes
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According to an online course, ribose and adenine can bond to make ATP. Is this true?

I recently came across this question in the MIT Open Learning Library Pre-7.01 Biology Course. It is question 2d in Problem Set 1 (archived link). The question, as well as the correct answers and ...
Ben Zelnick's user avatar
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Bi-phenyl degradation pathway in lignin

I am studying lignin - and really like the bi-phenyl degradation pathway of DDVA by SYK-6, as shown below But I can't find any literature on whether this pathway transfers from the dimer to the ...
erdos's user avatar
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How does a product form from a transition state in an enzyme despite the weak interactions being at its optimal

In the book Lehninger Principles of Biochemistry, there is a metal stick analogy to explain why an enzyme being compliment to its substrate would actually make a terrible enzyme. If the enzyme is ...
Pencilcase's user avatar
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How to convert Kilo Units (KU) to mg? [duplicate]

Im searching for AChE (Acetylcholinesterase) and on sigma-aldrich it is showing 2 KU or 2000U/mg of protein and on MedChemExpress it is showing 50mg then how can we calcute how much will be the drug ...
Shreyash Yadav's user avatar
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How can saliva neutralise acids produced by bacterial cells in our mouth if it is itself acidic in nature?

My school textbook makes the following claim: This means that saliva must be basic. However, I learnt that the pH value of saliva is about 6.8, which would surely make it acidic. How can the above ...
Golden_Hawk's user avatar
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Question on protonation/deprotonation of amino acid side chains

I understand that actual pKa of amino acid side chains is greatly influenced by the surrounding environment. I am trying to deeply understand the equilibrium between protonated and deprotonated form ...
Science123's user avatar
3 votes
2 answers
153 views

How does $\ce{H2CO3}$ form in the blood with a ratio of 1:20 with $\ce{HCO3-}$ if there are not enough $\ce{H+}$ ions

I have recently been studying about the bicarbonate buffer in the blood and have a doubt regarding the concentration of carbonic acid in the blood plasma. My understanding of the buffer system is that ...
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What's the grade of D-glucose that can be used in glucose assimilation test in bacteriology?

Background information Carbon assimilation test is based on the ability of a bacterial species to utilize an organic compound (e.g. D-glucose) as a sole carbon source. This means that for carbon ...
Freezing Soul's user avatar
1 vote
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Minimum growing conditions of a given plant

Micro-algae are organisms that can grow in aquatic environments and use light and carbon dioxide (CO2) to create biomass. Researches showed that Micro-algae biomass can be used as bio-fertilizer. My ...
Wissem Boujlida's user avatar
-2 votes
1 answer
507 views

Is Eugene Koonin's probabilistic argument for the necessity of a multiverse to explain the origin of life sound?

About Eugene Koonin Eugene Koonin, Ph.D. NIH Distinguished Investigator Evolutionary Genomics Research Group NLM/NCBI Dr. Koonin graduated from Moscow State University, Moscow, Russia and received ...
Mark's user avatar
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Compute a melting temperature in viennaRNA?

Posting here to get views, but may be more appropriate for bioinformatics or chemistry SE. There are a variety of utilities such as biopython or primer3 that compute melting temperatures. However, ...
Maximilian Press's user avatar
4 votes
1 answer
56 views

Allowed Deviations in fixed bond length and bond angles in peptides from the typical values

I am using frag builder python module to generate peptide structures to compute the interaction energy for ensemble of peptides of a given sequence for a fixed bond lengths and bong angles. However, ...
vigneshwaran kannan's user avatar
1 vote
0 answers
325 views

What are major obstacles that OOL research still has to overcome in order to come to a full understanding of how life could have arisen from non-life? [closed]

Dr. James Tour recently uploaded a video titled Dr. James Tour vs Dave Farina | Are we clueless about the origin of life? #abiogenesis. The description in the video says: Join us for an exciting ...
Mark's user avatar
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How is bio electricity modulated experimentally? [closed]

In the research performed by Micheal Levin et al, the morphological changes induced by changes in bio electricity are well demonstrated, most strikingly in his experiments in planarian worms. Yet ...
Evamentality's user avatar
2 votes
1 answer
116 views

Aerobic respiration takes place in the mitochondria; anaerobic respiration takes place in the cytoplasm. Is there a biochemical reason for this?

According to hyperphysics.edu, and my general knowledge, anaerobic respiration occurs in the cytoplasm. ("Anaerobic respiration (both glycolysis and fermentation) takes place in the fluid portion ...
haypreguntas's user avatar
1 vote
1 answer
61 views

Pathway where carbon dioxide captured by phosphoenolpyruvate is not re-released?

I have been reading about C4 carbon fixation in which CO2 is captured by phosphoenolpyruvate (PEP) to make oxaloacetate. Are there known pathways in plants that use substantial amounts of this ...
Polypipe Wrangler's user avatar
5 votes
2 answers
374 views

What is the energy of activation of uncatalyzed ATP hydrolysis reaction? Say in aquous solvent?

By ATP hydrolysis, I mean the chemical reaction: ATP + Water -> ADP + Pi. Focusing only on the reaction, this is a nucleophillic substitution reaction, most likely occuring in SN2 mechanism. But so ...
Anik Samiur Rahman's user avatar
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Resazurin not turning pink

I want to add resazurin to my media as an anaerobic indicator. To my understanding, the resazurin is blue when first added to the media, then turns pink after autoclaving, and finally it turns ...
David Madrigal Trejo's user avatar
2 votes
1 answer
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Why doesn't the cell just use one messenger?

I recently learned the second messenger model, where adrenaline activates adenyl cyclase, which converts ATP into cAMP. Then cAMP acts as a second messenger which activates portein kinase enzymes. The ...
Bruce M's user avatar
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2 votes
1 answer
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Why is iron transported across membranes in the ferrous form?

Iron in the diet of animals is predominantly in the ferric form, but it must be reduced to the ferric form by a specific ferrireductase before it can be transported across the cell membrane into the ...
Karthikeyan's user avatar
-1 votes
1 answer
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Why are odd numbers of chromosomes (triploidy, pentaploidy) less common than even ones (tetraploidy, hexaploidy)?

Perhaps there is an obvious reason, and I know that most organisms that are either exclusively sexual or at least capable of sexual reproduction are diploid, but.... Is there a specific reason ...
Kurt Hikes's user avatar
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1 answer
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Lipid Bilayer composition

I am currently taking a course on introduction to biomolecules and the other day our professor showed us a photo describing the composition of lipid bilayers of various organelles in a eukaryotic cell....
Preetham Karki's user avatar
8 votes
1 answer
261 views

Recycling of nitrogen in hibernating mammals

Hibernating mammals are required to undergo profound changes in metabolism. In addition to the more studied requirement of providing energy, there are problems in relation to nitrogen metabolism ...
Aseku Vena's user avatar
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Can you perform D-glucose assimilation test for a bacterial strain without API kit?

Background facts: Glucose assimilation test is based on the ability of a bacterial species to utilize glucose as a sole carbon source. The test is designed to determine whether the organism can use ...
Freezing Soul's user avatar
2 votes
0 answers
38 views

Cellular respiration and membrane surface protons

The final product of cellular respiration is the proton motive force, formed by protons pumped out of the membrane and by the voltage due to all charges. While Mitchell’s original theory considered ...
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