The scientific study of chemical processes in living organisms, including, but not limited to, living matter.

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Finding the thermodynamics of protein unfolding from temperature and absorbance using fluorescence spectroscopy?

I recently did an experiment on protein unfolding using a Perkin Elmer fluorescence spectrometer. The protein was $\alpha$-chymotrypsin. I was given this paper for my procedure. I am now trying to ...
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5 views

Ethanol in gas & impact to old plastic motorcycle gas tanks

I recently began refurbishing a 1980 Suzuki dirt bike with a plastic gas tank One week after filling the tank with gas containing ethanol the tank developed a 5 inch long split. Is this caused by the ...
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43 views

Can we repair a dead body?

The following passage has been extracted from the book "Organic Chemistry-10th edition by Solomon and Frhyle": "The growth of living things from microbes to elephants rests on organic reactions, ...
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1answer
25 views

What is the Chemistry behind “good” and “bad” cholesterol & their relation to Cis/Trans fatty acids?

I have searched Google for this but cannot seem to find an explanation. My question is as follows - what is the Chemistry/Biochemistry behind cis and trans fatty acids resulting in "Bad" LDL and ...
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16 views

How to find the concentration of a stock solution? [closed]

I have 80 mg of RES (0.08 g), which I want to dilute it with 6.4 uL (micro liters) of DMSO. This will be my stock solution. The molar mass of RES is 228.24 g. How can I find concentration of this ...
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13 views

Can I break starch down into glucose units?

I was wondering if starch can be broken up into individual glucose units. Because on a site I saw, it said that through acid hydrolysis starch can be broken up into amylose and amylopectin. However, ...
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15 views

What would make guanidinium ions and urea more effective denaturants of proteins in some cases, but not in others?

Some proteins do not unfold, or only partially unfold due to chaotropic agents such as guanidinium ions and urea. What are some reasons for this?
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13 views

How to detect azide group on a primer?

I bought azide-labeled primer for click chemistry, but it didn't work. So I want to prove the existence of azide group. How could I achieve this? I found a method to add ...
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1answer
36 views

Why does pasta become sticky after being cooked?

This question was posed by my biochemistry professor at the end of a class and then never answered. What I've gathered is that: It has something to do with the denaturing of a protein, since we ...
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1answer
30 views

How does dimethyl sulfoxide transport other molecules through skin?

Wikipedia says: Use of DMSO in medicine dates from around 1963, when an Oregon Health & Science University Medical School team, headed by Stanley Jacob, discovered it could penetrate the skin and ...
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3answers
56 views

What is tryptose

Occasionally, I work with lauryl tryptose broth for growing coliform. Being a chemical engineer, I suspected at the start that tryptose is a type of carbohydrate because of the -ose syffix. However, ...
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1answer
30 views

What makes something biodegradable?

Learning about biodegradable polymers and non-biodegradable polymers. What exactly sets them apart though? Here's the formula from wikipedia for the biodegradable PHB: and here for polypropylene, ...
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1answer
318 views

Why do many pharmaceuticals contain fluorine?

What exactly does fluorination of some compound do in a biological sense? I read the following things about what fluorine does for drugs: Fluorine withdraws electron density and can make an acid ...
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14 views

Drabkin Method for Hemoglobin Determination

Good evening, I have done several measurements of whole blood diluting it in Drabkin's solution. I need to plot calibration curve but I don't know how to. The concentration calculation is done by this ...
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2answers
41 views

Why is mercury much more toxic when inhaled than injected?

Following wikipedia: Cases of systemic toxicity from accidental swallowing are rare, and attempted suicide via intravenous injection does not appear to result in systemic toxicity,[1] though it is ...
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6answers
7k views

Do all salts taste salty?

Recently, I am learning the production of soluble and insoluble salts. My friend and I have done this experiment at the school lab. However, we want to taste them to see whether they are salty are ...
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65 views

Histidine-Phosphate in Succinyl CoA synthetase and phosphoglycerate mutase enzyme

I would need to know the type of bond of histidine-phosphate in succinyl CoA synthetase enzyme. Can anyone help with this? Is it a Carboxy phosphate anhydride ? Is it the same type of bond of ...
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0answers
27 views

Grapefruit and sugar gelatin like substance

More or less I am trying to figure out how this reaction occurred, so I can reproduce it. On a plate I had an excess amount of sugar with a fair amount of grapefruit juice which was stuck to the ...
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4answers
123 views

Storage of Urine

Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at ...
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1answer
34 views

Denaturing of Proteins and Nucleic Acids - Effect of Temperature (Heating VS Cooling)

Heating a protein/nucleic acid will disrupt inter-molecular and intra-molecular forces in the tertiary structure. It will also interfere with the shape of the active site if the protein. Does this ...
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0answers
31 views

Why would ethanol or water give poor yields in a peptide deprotection hydrogenolysis?

A homework question asks: The following reaction was carried out using ethanol or water as solvents, but gave poor yields in both cases. Suggest why this might be the case and how these problems ...
2
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2answers
55 views

Why is iron used in the body?

I'm writing a report on the spectrophotometric determination of iron. In my introduction I want to briefly explain the importance of iron in the human body. Wikipedia states that "Iron is essential ...
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1answer
19 views

How does one analytically quantify whether or not a compound is a SIRT1 activator?

So there has been a lot of noise over whether or not certain molecules activate SIRT1. Resveratrol was thought to be a specific SIRT1 activator, but many have argued against this claim. Similarly, ...
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2answers
20 views

Optical Density numbers

If it's OD of 600nm I know that's the wavelength used, but what are the other numbers in something like "OD 600nm of 0.6-0.7". The 0.6-0.7?
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1answer
62 views

Net charge of Peptides at pH1 and pH0

Taking Glycine and aspartic acid. As both the amino acids are fully protonated at pH 0 ad pH 1, how does the peptide bond form? Is it a two step mechanism where the OH from an alpha carboxyl group ...
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11 views

How to calculate the amount of a polymer (PCL) in the chloroform:dimethyl sulfoxide (7:3) to get 9% solution?

I need to calculate the amount of the polymer [mg] in the chloroform/dimethyl sulfoxide with the ratio 7:3 relatively for producing 9% solution. I was using this formula for dissolving the polymer ...
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1answer
78 views

Why do glucose, galactose and mannose differ in solubility in water?

I don't understand why they would be so different, when the only structural difference is the orientation of hydroxyl groups.
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2answers
200 views

Are all anomers diastereomers?

I am told that all anomers are diastereomers. I think this is BS. If there is a carbohydrate with only one chiral center, then changing the configuration of the anomeric carbon gives us enantiomers. ...
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3answers
812 views

what does the '-1' superscript mean in units?

For example, the rate of a chemical reaction can be expressed in $\mathrm{mol}/\mathrm{L}^{-1}/\mathrm{sec}^{-1}$. Why is it '-1' and not, say, '-2'? Does it change the meaning if the minus is removed ...
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0answers
25 views

How to plot standard curve using D-Galactouronic acid

I wanted to calculate the Pectinase enzyme activity. so how can I plot standard curve using D-galactouronic acid ? also is it possible using glucose ?
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1answer
43 views

In water, will sucrose be hydrolysed by water to form glucose and fructose molecules?

If I dissolve sucrose sugar ($\ce{C_12H_22O_11}$) in water, would the water readily hydrolyse the sucrose sugar to form glucose and fructose sugars?
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1answer
37 views

How does aminoguanidine interfere with the formation of advanced glycation endproducts?

This says that aminoguanidine interferes with the formation of advanced glycation endproducts (AGEs) through interacting with 3-deoxyglucosone. But how does it interact with 3-deoxyglucosone that ...
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0answers
18 views

Why is cytosine far more vulnerable to hydrolytic deamination than both adenosine and guanosine?

Here's the source for the claim (the half-life is 340 years at 298 K, which is much smaller than that of adenosine and guanosine).
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17 views

Why is LDL more easily oxidized/damaged than HDL?

By LDL and HDL, I mean the lipoproteins that carry cholesterol. Oxidation of LDL ultimately contributes to heart disease.
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27 views

Why is N7 of guanine so vulnerable to addition via alkylating agents? [closed]

Especially compared to N7 of adenine and the other nitrogen atoms of guanine?
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1answer
37 views

Why are so many different organophosphates able to deactivate acetylcholinesterase?

From sarin to http://en.wikipedia.org/wiki/Tricresyl_phosphate, there are such a huge diversity of them that can do it. What's so special about the simple organophosphate group that makes them able ...
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1answer
53 views

Explicit differential equation based model of protein folding

I am an applied mathematician interested in the dynamics of potential systems - i.e., systems with multiple unique energy minima. One of the best examples of such systems are protein folding ...
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22 views

Is catechol (o-dihydroxybenzene) more prone to auto-oxidation than p-dihydroxybenzene or m-dihydroxybenzene?

And if so, why? Apparently, both dopamine and caffeic acid are prone to auto-oxidation. So I wonder if it's a property of o-dihydroxybenzenes in general.
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2answers
131 views

How can a protein folding transition state have zero lifetime?

I'm doing a module on my Biochemistry course looking at protein folding, and in a discussion of [folding] transition states I was a little confused at the thought of a zero-lifetime transition state - ...
5
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1answer
44 views

How to analytically quantify a chemical's potential to intercalate DNA?

This shows that polyphenols (like quercetin) have the potential to intercalate DNA, but at potency 100x less than that of ethidium bromide. How does one analytically measure/quantify "100x weaker"? ...
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1answer
53 views

How does sulbutiamine work in the same way as thiamine, even if it doesn't have a thiazole ring?

So sulbutiamine is said to be a thiamine substitute. Yet - it doesn't contain the thiazole ring that's so important for many of thiamine's functions.
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30 views

What are the metabolites and method of action of Contrave, Belviq or Phentermine?

The SE staff spurred me into wondering about diet pills. What are the metabolites and method of action of Contrave, Belviq or Phentermine?
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51 views

Algorithm that calculates damage from adrafinil?

is there such a thing that calculated damage of adrafinil based on dosage? lets say i take a dosage of 100mg/ day for 100 days, what would the affect be? how much % of my liver will be damaged? Do ...
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1answer
62 views

ATP break down and energy release?

I have a very basic question. Energy is absorbed to break bonds. Bond-breaking is an endothermic process. Energy is released when new bonds form. Bond-making is an exothermic process. But ATP breaks ...
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0answers
28 views

How do I figure out where velocity declines?

I am stumped on one question on my biochem practice problems. We went over all of them today but my whole group was unable to figure out how to properly set up the equations to calculate the change in ...
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1answer
53 views

What trends affect hydrophobicity in amino acids?

I was wondering if the length of the carbon backbone affects hydrophobicity of amino acids (i.e. longer carbon backbone of side group = less polar = more hydrophobic).
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19 views

Procedure of Hydrate Lab

How do you find the formula of a hydrate when given an impure substance? Is there any procedure to find this out in a laboratory setting?
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1answer
32 views

How does life choose it's nominal temperature preferences?

If all life relies on water, and water freezes at 32F and boils at 212F. Then why isn't the nominal temperature for life 122F? 122F will literally kill some animals, including us. Do our ...
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39 views

Delta G values for Pyruvate--> Alanine vs. Oxaloacetate -> Aspartate ->Asparagine

What are the delta G values for the mammalian (human) biosynthesis of alanine from pyruvate, and for the conversion of oxaloacetate to asparagine? (assuming no particular cellular restriction or other ...
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205 views

Influence of Temperature on Biochemical Reactions

Short question How (quantitatively speaking) does temperature influences rate of decay of proteins? I am looking for some general number/function, the influence of temperature on an average protein. ...