Questions tagged [biochemistry]

This tag is for questions concerning biochemical methods (e.g. electrophoresis) or those concerning biochemical mechanisms or research. Do not use this tag if your question is merely about compounds often used in areas related to biochemistry or associated with these. These may fall under organic chemistry or the appropriate compound’s functional groups’ tags.

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6 views

How can determine galactose and mannose by GC-MS if its elute same RT in 5MS column? We have only galactose standard

How can determine galactose and mannose by GC-MS if its elute same RT in 5MS column. We have only galactose standard and galactose only should quantityfy, but the peak of galactose standard also ...
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pKa values for amino acid

To calculate the pI value, we take the average of the pKa values from the 2 groups that result in a net charge of 0. For that to happen, the pKa values should be at the midpoint of titration where ...
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What would happen if you swallow NAC and Acidophilus pills right after taking alcohol? [on hold]

You drink 30 grams of 40% rum with few ounces of water and then swallow a few supplements that are supposed to be taken on an empty stomach. NAC and Acidophilus. Besides the water and alcohol, the ...
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1answer
21 views

What ratio of bicarb to sugarcane juice with a pH level of 4.5-5.5 to neutralize pH level?

I am thinking of adding baking soda to sugarcane juice to eliminate the fruity acid that is present. The pH of sugarcane juice ranges from 4.5-5.5. I wonder how much baking soda should I incorporate ...
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1answer
23 views

The time-dependent pH value in a fermentation

I want to know if someone has supporting tips or solutions to my problem: In biotechnology, fermentations are used to grow microorganisms. These need a specific media/broth in which temperature, pH, ...
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2answers
64 views

Why do chiral biological molecules only exist as one enantiomer? Does it have any advantage?

Why is it that chiral biological molecules are enantiomerically pure? The other enantiomer would have the same reactivity, and the only difference is their angle of rotation of plane polarized light. ...
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2answers
7k views

Why isn't aluminium involved in biological processes?

There are so many biological processes which are dependent upon ions of lighter metals (upper part of periodic table) such as $\ce{K+}$, $\ce{Na+}$, $\ce{Mg^{2+}}$ and even early transition elements ($...
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2answers
37 views

Bleaching of chlorophyll stains using hydrogen peroxide

I have been doing some experiments concerning bleaching of chlorophyll stains from cotton clothing. Currently I have found that $\ce{H2O2}$ is fairly effective, but still leaves visible stains. Would ...
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17 views

Why no specifications for the concentration of Phosphate buffered saline buffer?

I am following a protocol where they use PBS buffer. But they don't specify the concentration of PBS, why is that? How am I supposed to know how to make this buffer if I don't know the concentration ...
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27 views

Protein purification pressure limits confusion, about the X-MPa limit for FPLC?

I have always been a bit confused about column pressure limits. I have to elaborate a bit on the problem to get to my question: In protein purification we use the äkta purification machines (e.g. ...
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25 views

Difference between Ascorbate & Semi-DHA (both C₆H₇O₆)

I wanted to know how Sodium Ascorbate functions in the AA family of molecules. However, all normal routes lead to dead ends (typically AA). Forcing NCBI to search only for Sodium Ascorbate mostly ...
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1answer
190 views

Does cooling a potato change the nature of its carbohydrates?

A talk-show guest of Joe Rogan claimed that cooling a potato after cooking creates "resistant starch" that's better for human consumption https://www.youtube.com/watch?v=niwqfwA2Lb8 The claim is ...
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19 views

What is the cause for the difference in pH between NaCl and Ringer Lactate

Reading this article, I came across a passage which got me to think of this question: "Normal saline contains approximately $\pu{154mM}$ of each $\ce{Na+}$ and $\ce{Cl-}$ with average pH of 5.0 and ...
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3answers
68 views

what is the difference between how taste and smell are detected?

Taste and smell are both chemical processes ... parts of the food dissolved in saliva come into contact with the taste receptors.[1] These are located on top of the taste receptor cells that ...
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2answers
57 views

DNA-Sequencing (detection of the change of pH-value) after emulsion PCR

I have troubles with understanding the exact order of the steps for DNA-sequencing after the Emulsion PCR (EmPCR). The EmPCR fills each bead with the same DNA strand (copies it $n$ times, till the ...
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2answers
138 views

Derivation of time probability distributions for single molecule kinetics

If we have a protein $\ce{A}$ that can bind to protein $\ce{B}$: $$\ce{A + B <=>[$k_\mathrm{fwd,1}$][$k_\mathrm{rev,1}$] AB}$$ and the bound complex $\ce{AB}$ can be converted into $\ce{C}$: $...
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1answer
76 views

Hill equation with inhibition and activation

The Hill equation for an activating enzymatic interaction with cooperative multiplicity $n$ is $$\frac{\mathrm d[\ce{P}]}{\mathrm dt} = V_\mathrm{max}\frac{[\ce{S}]^n}{K_\ce{S} + [\ce{S}]^n}\tag{1}$$ ...
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1answer
96 views

How are glycosidic linkages formed?

Consider glycosidic linkages in disaccharides. I know a condensation reaction occurs, with the loss of water. But which OH is lost? The O in the linkage belongs to which monosaccharide? Example: ...
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0answers
77 views

Why is there no effective alternative to metal salts in antiperspirants?

Metal salts, especially aluminum compounds are used in antiperspirants to prevent sweating. I found out aluminum chloride hexahydrate, which is found in most antiperspirants, undergoes an acid-base ...
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1answer
37 views

How do cells form a solid structure? [closed]

How do cells unite to form a solid structure. For example a plant body is made up of a number of cells. The cells are not solid structures. Their consistency is in between solid and plasma. So how ...
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1answer
25 views

Purification of Solid Phase Synthesized Peptide

I began working in a newly setup lab, and I'm having a dilysine (K2) peptide synthesized by solid phase method. I plan to cleave the peptides from the resin with a cleavage cocktail of TFA. ...
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1answer
37 views

Is hydrolysis of polypeptides and polysaccharides “anabolic” or “catabolic”

When a polysaccharide or polypeptide is hydrolyzed into mono-saccharides or amino acids, the building blocks can be oxidized to release energy. The oxidation is considered to be catabolic since it ...
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1answer
27 views

What is the chemical equation for the digestion/decomposition of cellulose?

I'm trying to find the chemical equation/pathway from cellulose $\ce{(C6H10O5)_n}$ to methane $\ce{CH4}$. What are the other reactants or products in the reaction? $$\ce{C6H10O5 + ? -> CH4 + ?}$$ ...
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19 views

Flow of electrons DNMT [closed]

In a paper about the modes of action of DNMT, it said there an increased flow of electrons to carbon 5 following the formation of a covalent bond between DNMT and carbon 6 on cystine. Why is this? ...
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3answers
66 views

What is the precise definition of Ramachandran angles?

The Wikipedia article Ramachandran plot is very schematic and doesn't even say when these angles are considered to be zero. It seems to assume that the peptide chain has no end, and always shows the ...
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23 views

Which Flocculant/Coagulant is ideal for harvesting Algae?

While dealing with Algae fit for human consumption (as protein supplements), which is the most suitable coagulant/Flocculant available? Factors to consider: 1) Cost Effectiveness (for instance poly ...
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1answer
76 views

Why is molybdenum that important in inorganic synthesis as well as biosynthesis of ammonia?

We know that Mo (Molybdenum ) is used as a catalyst for Haber's process, during synthesis of Ammonia from Nitrogen. Again, in biological systems, Nitrogen fixation (ALSO forming Ammonia from Nitrogen)...
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21 views

Terpene cyclization on terretonin biosynthesis

I would like to ask about a terpenoid cyclization in terretonin biosynthesis in a research paper authored by Matsuda et al., Curr. Opin. Chem. Biol. 31, 2016. It is showed in the paper that The ...
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1answer
72 views

Can glucose and insulin exist in the same container without reacting?

Someone asked if glucose and insulin could be mixed in the same container and used as an injection to provide a quick energy boost. I'm not interested about the medical part of this question, but just ...
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2answers
54 views

When amino acids react with each other, how do you know which one reacts using it's carboxylic group and which one with it's amine group?

For example the dipeptide val-ser, between the amino acids valine and serine, does valine's amino group react or does it's carboxylic group with serine's respective group?
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1answer
61 views

Histidine vs Lysine

Among the amino acids, histidine and lysine, which is more basic? And why? I tried protonating and checking electronic effects but couldn't reach a satisfactory conclusion.
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15 views

Why a Differential Scanning Calorimeter (DSC), to measure thermodynamic parameters, has problems?

I want to use a Differential Scanning Calorimeter (DSC) to determine when my protein unfolds as you increase the temperature in a DSC machine. The machine is pressurised (to 3A) during the run, so ...
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21 views

Predicting Glycine-HCl's multiple equivalence points

I have currently completed a titration curve for glycine-HCl (2omL @ 0.1M, therefore 2.0mmol) where I have the known pH at each interval of added NaOH (adding 4mL each interval of 1.0M then measure pH)...
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24 views

What is the difference between oxalacetate and oxaloacetate?

What is the difference, if any, between oxalacetate and oxaloacetate? Is the former archaic nomenclature? Thanks
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29 views

How to recreate bioluminescence in fireflies in a lab?

I have several mg/mL of D-luciferin, luciferase (firefly), ATP solution (25 mmol) and MgSO4 (for the mg2+ ions). The experiment has to be done in cuvettes of 2,5 mL (if I get any results, it will be ...
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2answers
39 views

Help required for the calculation of moles [closed]

If 4.5ml of yeast prep + 0.5ml of 0.25 M glucose is separated into 2ml in 2 similar flasks. How many micromoles of glucose are there in one flask? Using M1V1=M2V2 (0.5ml/1000)*0.25M = M2 * 2ml = 0....
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20 views

why do cone cells have broad responsivity spectra peaks?

My understanding of vision is that, although the cone cells in our eyes can detect three colors, there is enough overlap in the responsivity spectra (as shown here: https://en.wikipedia.org/wiki/...
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2answers
112 views

How to determine steady state of multi-step reaction with both reversible and irreversible steps?

I am trying to determine the relative concentrations of $\ce{U1}$, $\ce{U2}$, and $\ce{E}$ when the following reaction is at steady state. Note that $k_t$ is the zero order rate constant of new $\ce{...
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47 views

How can the ocean act as a buffer?

I was reading up on the buffering effect of the ocean and I was quite confused about how the buffer is able to do anything. The buffer I will refer to is below: $$\ce{CO3^{-2} +H2O <=> HCO3 + OH^...
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2answers
164 views

How does existence of alpha and beta form of glucose prove that it exists as a cyclic structure

My book says that Glucose is found to exist in two different crystalline forms which are named as $\alpha$ and $\beta$. Next it says that This behaviour could not be explained by the open ...
2
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1answer
76 views

Why is copper(II) sulfate added drop by drop during the Biuret test?

The Biuret test is a test for proteins. The procedure is to add a strong base, such as NaOH, to dissolve the protein. After that, copper(II) sulfate is added drop by drop into this until a (violet) ...
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2answers
58 views

Measuring a high Michaelis constant using fluorescence

We have the task of measuring kinetic parameters of an oxidase reaction that has a $K_M$ of about $2 \,\text{mM}$. For that, we want to use a fluorescence assay based on Amplex Red. The latter is a ...
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1answer
35 views

Can someone suggest me method to extract carotenoids? [closed]

I want to extract carotenoids, but want to use some inexpensive method. can you suggest me some method?
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1answer
53 views

Why would decreasing ionic strength of buffer disrupt hydrogen bonds

I'm reading about cDNA synthesis in my textbook and it mentions that: The captured mRNAs are subsequently released and collected, for example, by decreasing the ionic strength of the buffer so that ...
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2answers
76 views

What happens during Glycolysis? [closed]

Can I get brief explanation of the reactions that occur under Glycolysis? What do the curved lines represent?
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1answer
49 views

Complementary base pairing

In the molecular structure of a DNA it is seen that purines (adenine and guanine) bind with pyrimidines (cytosine, uracil and thymine) through hydrogen bonds, and this is always between a purine and a ...
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43 views

What's causing this dip in the FCS curve?

This is a fluorescence correlation spectroscopy measurement of light harvesting complexes. What could be causing the dip at 100 microseconds? Edit: The same thing was observed using fluorescence ...
2
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1answer
58 views

Make paper from hair? [closed]

Hair is fibrous... Is there a good reason, why we don't recycle our own hair (and clothing, what have you) into paper-products? (rather than cutting down trees)?
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1answer
48 views

What would happen if we had a different kind of metal in our bloodstream? [closed]

It is a common fact that we have iron in our blood. But what if we had something different in its place? Like instead of iron what if it was copper, or silver, or what if we had gold in our blood ...
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1answer
44 views

Opening the imidazoline ring in tolazoline

Hello. I was studying about the alkaline ring opening or purines. While doing research, i came across this compound. This got me thinking if we can use the same procedure to open the imidazoline ring ...