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7

The bacteria in the foregut of cud chewing animals (e.g. cows) provide enough B12 and other B vitamins. Uptake of B12 happens mainly in the small intestine. There are lots of bacteria in the human intestine but most fermentation of plant matter happens in the hindgut. Hindgut fermentation also produces B12 but since this happens past the small intestine it ...


5

Pure nicotine is a yellow colored liquid (although some sources say it's a clear liquid.) "Tar" is a complex sludge that is also yellow-brown. So it's difficult to distinguish 'nicotine stain' from a 'tar stain' based on visual inspection. Let's go to other considerations. The concept of a 'stain' implies that simple hand washing doesn't remove the ...


4

Given your background (not a biologist or chemist) you would probably find the introductory material in a biochemistry "lite" textbook more accessible/useful than a hardcore text for specialists. As a co-author of a biochemistry textbook, I can tell you that there are essentially three different classes, or types of texts. Comprehensive textbooks, of ...


4

You could measure OD at 340nm. If OD340 is much lower than expected, NADPH is oxidized and does not have much biochemical activity. http://www.bmglabtech.com/media/35216/1043734.pdf


4

It is just a way of highlighting your search term. If you search M00115+C03722, you will see C03722 in red.


3

Transcytosis is a process by which large macromolecules are transported across a cell, such as those in the intestinal epithelium. It is used by many toxins and even whole organisms to enter the body. Botulinum toxin also apparently uses this mechanism. I'm not sure how detailed of an answer you want, but the linked to-review is pretty in-depth.


3

There appears to be either a typo or transcription error in your textbook. According to this Nuffield Foundation and Royal Society of Chemistry article Molecules of most detergents and soaps are long chain hydrocarbon molecules with an ionic group at one end, usually carrying a negative charge, thus making it an anion. This charge is balanced by ...


3

Short answer Tar deposition is the cause of the yellow cigarette stains. Background Both tar and nicotine cause yellow to brown staining. Although nicotine itself is colorless/white, it turns yellow upon exposure to air. In a study on cigarette stains, the author speaks of tobacco-tar stains, implicitly acknowledging it is tar and not nicotine (John et ...


2

In my experience, half an hour at room temperature will make absolutely no difference. Boehringer, who at one time supplied the best NADPH, used to recommend storage at 4 degrees Celcius. NADPH is typically about 85% 'pure' by dry weight measurements, and Sigma will try to tell you that the remainder is mainly water. That is, if you calculate a ...


2

This is somewhat outside my field, but basically it seems they're defining the independence of the three hypothetical metabolic pathways in two different ways: Mathematically the pathways are not independent since P₃ is a combination of P₁ and P₂. Biologically the pathways are independent since each requires a different combination of enzymes and ...


2

I work with membrane proteins and in my experience some proteins can be frozen and thawed without any problems, other proteins just don't like that. It's linked to the stability of the protein. If you really need to freeze the protein you may think about playing around with different detergents to see if you can improve the stability of the protein. General ...


2

I want to add a book to the list that may be easier for you since it takes it from the perspective of Physics: Finkelstein & Ptitsyn, Protein Physics, Academic Press (2002). ISBN 0-12-256781-1. It covers structure, thermodynamical processes in proteins, mechanism of folding, function, a bit of bioinformatics. It is designed as a master level course in ...


2

Xenon. It is like an ideal anaesthetic. See here. Xenon is an interesting anesthetic as it appears to lack negative inotropicy and vasodilatation, giving great advantages to both patients with limited cardiovascular reserve or those who require hemodynamic stability. It has low toxicity and is not teratogenic. Xenon gives rapid induction and ...


2

That module represents Entner-Duodoroff pathway, which is an alternative pathway to the Embden-Mayerhof-Parnas pathway of glycolysis. Entner-Duordoff pathway exists only in prokaryotes.


2

I think when they sent it to you without dry ice, it is probably OK to store it at room temperature. Sigma seems to advise on their NADPH to store dehydrated NADPH at room temperature, while they advise to store the hydrated forms at -20oC. Likely the presence or absence of molecular water in the material is crucial for its storage. disclaimer: I am not ...


1

These two concepts are not mutually exclusive. You have constructed a false dichotomy. Both of these facts are true: The electrons in the pi orbitals of the conjugated double bonds in the planar rings are hydrophobic. The nitrogen and oxygen molecules (either in the rings, or as substituents on the rings) can participate in hydrogen bonds. There are ...


1

High and low are not very descriptive since they are relative. ATP hydrolysis may have a high activation energy compared to some reactions and low when compared to others. The important point is that the activation energy is sufficiently high enough such that ATP is not rapidly hydrolysed under physiological conditions before it can do useful work. In other ...


1

Propofol: a widely used i.v. anesthetic with GABA agonistic properties. It has to be given continuously i.v. When stopped, effects wear off in minutes, and recovery is without serious side effects and little nausea. Induction is quick (minutes or less) since it is administered i.v. Aminophylline (theophylline ethylenediamine), an adenosine receptor ...


1

Nanodiscs are very powerful technology for membrane protein invented in Stephen Sligar's lab at the University of Illinois. A nanodisc is composed of a membrane protein, lipids and two monomers of a "scaffold protein". The most used scaffold protein is an N-terminal truncation of apolipoprotein A-1 (apoA-1), which is the primary protein component of ...


1

Surface tension is about how much energy you need to create new surface between not mixing materials e.g. water and lipids. Surfactants like bile makes this easier (lowers the energy required). So they can form small bubbles of lipids: micelles, which can be handled much easier by the digestive system. Another usage of surfactants to make foams, creams, ...


1

TL;DR : Food gives the human body much more than simply vitamins & minerals. A healthy diet is essential to overall healthiness, not just this one aspect of it. Micronutrients The component you're asking about - vitamins & minerals - are referred to as "micronutrients", and is only a quarter or so of what the body needs. Micronutrients are the ...



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