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It's the same stuff that makes up most sea shells, calcium carbonate, $CaCO_3$. Incidentally, this explains why egg shells dissolve in vinegar (acetic acid which, since it is an acid, provides the Hydrogen ions in the reaction below): $CaCO_3+ 2H^+ -> Ca^{2+} + H_2O +CO_2$ This simple reaction (which is what would happen in your stomach as well) ...


7

This question really belongs at Chemistry.SE, but I'll give you a quick answer. A substance is soluble in water when its solid form (such as a sugar cube) completely dissolves in water to become a sugar solution. The sugar molecules themselves are unaffected, essentially - instead of all being bound to one another in a crystal, they are now floating around ...


7

According to the abstract from this paper, the intragastric LD50 of $\Delta^9THC$ (tetrahydrocannabinol) in sesame oil using Fischer rats was 1270 mg/kg. Assuming rats and humans are identical (they're not), for an average-sized adult human weighing 70 kg (~155 lb.), the median lethal dose would be 88.9 grams, or about 3.1 oz. Keep in mind that's 3.1 oz. of ...


7

The comment of the poster to my request for clarification cites “The formation of ammonia itself requires… large quantities of water to dilute it out of a biological system” I conclude that he assumes that the problem with animals eliminating ammonia as such is one of solubility in water. This is not the case. The solubility of ammonia is such that saturated ...


6

If they perform the exact same function, they can be considered the same functionally. Hemoglobin in most humans is the same, down to the amino acid sequence; the hemoglobin in sickle cell anemia, Hemoglobin C, Hemoglobin SC, thalassemia, and others are all different by at least one amino acid, yet they are all hemoglobins, and all do the same job: they ...


6

Human and mouse titin are orthologs, and can be confirmed through an NCBI query for TTN. Orthologous proteins are not the same, per se. They retain the same function, and basically result from speciation: the common ancestral gene got divided between two species. However, the sequence may potentially differ because obviously the species have diverged. ...


6

The minus sign in parentheses here indicates the optical rotation, (+) means the molecule rotates linear polarized light clockwise, (-) means it rotates counterclockwise. Typically you would also write exactly which stereoisomer is meant (R or S), which is generally the more useful information. The following are all valid names for the natural stereoisomer ...


6

According to the sigma document you referenced (emphasis added by me): "The free acid is soluble at 0.24 g/L in water at 15ºC, while the sodium salt is soluble at >333 g/L in water at 15ºC. Therefore, pH control is very important to the use of this product. Aqueous solutions precipitate as the pH is lowered to 5." According to the FDA document ...


6

If we change the question to "what is the minimum number of elements common to every form of life?", my lists would be as follows. (I am not considering either viruses or prions to be 'alive'). The following elements are surely common to all forms of life (List 1): H (1), C (6), N (7), 0 (8), Mg (12), P (15), S (16) [#7]. In addition, the ...


5

Short answer Assuming you wish to have a common name for both of these (widely differing!) pathways I basically agree with @Chris, and I would go for general terminology, namely metabolic pathways. Background The pentose-phosphate pathway is neither anabolic nor catabolic so those terms won't do. The pentose-phosphate pathway is, however, closely linked to ...


5

If you look at the Google ngram for the term ‘Molecular Biology’ you will see that it first appears just before 1960, and it is relevant that the Journal of Molecular Biology was founded in 1959. It is not biochemistry — indeed the name was meant to indicate its difference from biochemistry, and I heard second-hand (so I cannot vouch for its truth) that Hans ...


5

This is a question I also remember wondering about when I was younger in school. Now as a professional it's way too obvious to even explain. But i think it's an important and common question, which warrants an example or two from common daily lab practice. Preface You have to understand that DNA is a molecule. It's really tiny. It's not trivial to work ...


4

Welcome to Biology.SE! Your question has nothing to do with evolutionary biology Evolutionary Theory does not explain the origin of life just like the Theory of Gravity does not explain the diffraction of light! In other words, explaining the origin of life is not within the scope of evolutionary biology. You should edit your title. But still, your ...


4

chemicalize.org is a good utility for predicting many molecular properties such as pKa, pI and charge. The Human Metabolome Database uses the same underlying software but tabulates some of the data (eg charge is explicitly stated). Acetyl-CoA, for example, has a pI of 1.32 and charge of -4 at pH=7.4. Your second link is to a portion of an enzyme (a ...


4

The first compound you mention is acetyl-co-enzyme A (acetyl-CoA) (first picture, left panel). The acetyl group is uncharged, but the co-enzyme A (CoA) group (Fig. 1, right panel) does carry charge through its phosphate groups. In normal physiologic environments these phosphate groups will donate one or more protons, leaving the molecule negatively charged, ...


4

Okay, he's not wrong, technically speaking. Practically speaking never ever fertilize your plants with ammonia. The ammonia you spilled will be converted into nitrates eventually, so it's not like you spilled lead into your garden. On the other hand the populations of nitrifying bacteria take a fairly long time to adapt to a bounty like "a bunch" of ...


4

Given your requirements I would go for the Alberts for molecular cell biology. For organic chemistry, in my opinion, there is no better book then the Clayden. It is targeted at OC students but I - as a biologist - learned a lot from it and still sometimes love to browse through it even though my work is far away from organic chemistry. In general, I would ...


4

Although you should be able to find bacteria that can grow on plastic, I think your criteria of 'not difficult to find' might be a challenging one to meet. Poly(ethylene terephthalate) (PET) is a commonly used plastic, and in 2016 Yoshida et al. discovered a species of bacteria, Ideonella sakaiensis, which can grow using PET as its carbon source. This study ...


4

We are dealing here with the quantities differing by (at least) two orders of magnitude: energy corresponding to 260nm radiation is about 110 kcal/mol (here is a converter) stacking energies of DNA double helix are of the order of 1 kcal/mol The change in the absorption energy due to electron delocalization when unstacking is thus smaller than 1 kcal mol, ...


3

"The only thing I need is the book to be easy to understand because it will most probably be totally self taught because our instructors are not always helpful in explaining stuff properly." I can understand the problem with the stream you are telling about; there is an outburst of information, but there is a severe shortage of correlating between ...


3

Interesting question. Here, the question actually comes down to how the bond actually looks vs how we depict the bond. In detail, see this image of maltose from here: Pay attention to the geometry of the glycosidic bond. From how it is depicted, one would conclude that it is straight in geometry. But how it actually looks is like this: Now, the obvious ...


3

Dietary fibers are the indigestible portion of food derived from plants. Most of these are indeed polymers of sugars (that is, a chain of repeated basic unit of carbohydrate), for example cellulose, alginate or pectin. They have glycosidic bonds that cannot be broken down by enzymes found in humans, and are thus indigestible. But there are exceptions, for ...


3

The Jaccard index is a measure of similarity between two sets. Take a look at the Wikipedia article here. It is very easy to compute: The Jaccard similarity coefficient for sets X and Y is defined as: J(X,Y) = |intersection(X,Y)| / |union(X,Y)| Where | | indicates the size (number of elements) of the set. Imagine you have two sets X and Y defined as ...


3

The constitution of the biogas depends greatly on its source and the fermenting microbe. But in general, it does contain hydrogen about 0-1%. Even if it did contain large amounts, the mixture would be inflammable, but it would not burst into flames without any external igniter, which could be any small fluctuation of heat if the mixture is too unstable. But ...


3

I am not so familiar with enzymatic kits for quantifying glutamine, but most enzyme-based analysis kits come with a number of fairly strong assumptions on the enzymology involved, and in my experience they are difficult to use reliably. Commercial kits are hopeless to troubleshoot since their components are not disclosed --- you don't know what you're ...


3

While I feel like this might be a better question for the chemistry SE, lets take a look at the molecular structures: The basic structure of a phenethylamine (left, modified from here) versus DEET (right, modified from here): The important chemical differences are: DEET only has a C-alpha between the nitrogen and the ring, whereas phenethylamines have a C-...


3

Since this question has no answer, I thought of taking a stab at it. Why does decomposing matter emit a bad smell? Due to cadaverine and putrescine. More information here: What produces the strong odor of decaying dead animals? Why do they smell so bad? Why do we perceive those smell as bad? Let's start from the basics. Stuffs smell because they release ...


2

This is only an partial answer, as I do not have the time now to look for other references. In the chapter about milk, Harold McGee's beautiful book "On Food & Cooking" says (pg. 21 of the 2004 edition, bold is mine): Flavors from cooking Low-temperature pasteurization slightly modifies milk flavor by driving off some of the more delicate aromas, ...


2

If your looking at transcription then your talking about RNA POLYMERASE. And there are many variants. Here's a good Nature paper that discusses temperature and RNA Pol http://www.nature.com/ncomms/journal/v1/n6/full/ncomms1076.html And another: http://www.ncbi.nlm.nih.gov/m/pubmed/12729734/ I couldn't get full access to this JBC paper but I think the ...


2

The tautomers are rare but they can form and it is suggested that tautomerization can lead to mutations because of non-cognate base pairing. Khuu & Ho (2009), have inferred the presence of adenine and thymine tautomers from the crystal structure of an in-vitro assembled holliday junction. They infer that imino-Adenine base pairs with amino-cytosine (...


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