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Everything posted by Yggdrasil
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This doesn't look like a clear acid/base reaction to me, but more like an oxidation /reduction reaction. The phosphorus is being oxidized while the hydrogens are being reduced to form hydrogen gas. Broken down the reactions probably look like a substitution reaction followed by an acid/base reaction: H2PO2- + OH- --> H3PO3- + H- Here the OH is acting like a lewis base (nucleophile) by donating its lone pair to form a bond with the hypophosphite (the lewis acid/electrophile). The hydride ion acts as a leaving group in this substitution reaction. Now comes the acid/base part of the reaction: H3PO3- + H- --> H2PO32- + H2 Here the phosphorous acid acts as the (Brønsted) acid and the hydride ion acts as the (Brønsted) base.
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Glial Cells and Intellect
Yggdrasil replied to Thales's topic in Anatomy, Physiology and Neuroscience
http://en.wikipedia.org/wiki/Glial_cells -
Life expectancies may have something to do with it. Females tend to live longer than males (I don't realy know the biological basis for this, although the basis may involve social aspects). For example, in the US, women live about 5 years longer than men.
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Rubbing alcohol or nail polish remover may work.
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stems cells vs pharmacists
Yggdrasil replied to Ice-cream's topic in Biochemistry and Molecular Biology
Therapeutic cloning is done in the same way as any other cloning process. The difference is the intended use of the cloned embryo. In therapeutic cloning, the embryo will be grown to the blastocyst stage and the stem cells will be extracted. In reproductive cloning, the embryo will be grown to the blastocyst stage then implanted in a surrogate mother so that the embryo can develop into a fetus and later a cloned baby. As for the actual process, the most common method is nuclear transfer. The nucleus of a donor cell (usually a fibroblast [skin cell]) is removed and implanted into an enucleated egg cell (an egg cell whose nucleus has been removed). The embryos are then cultured and grown to the blastocyst stage, where the inner cell mass, which contains stem cells, can be removed. Currently, this process is very inefficient. It has been done by a South Korean group, but "the team began with 185 eggs, produced 31 embryos and collected stem cells from 11 of those." Theoretically, the process could work for an eighty-year-old person, but the technology and expertise to make therapeutic cloning widely available is still years away. -
stems cells vs pharmacists
Yggdrasil replied to Ice-cream's topic in Biochemistry and Molecular Biology
Sorry for the double post: One disadvantage of embryonic stem cells is that they are not genetically identical to the patient. Therefore, upon transplantation, the patient's immune system may reject the stem cells. Adult stem cells would eliminate this problem as they would be extracted from the patient's own body, cultured into the appropriate cell type, and reimplanted. Under this procedure, there is little to no risk of rejection, because the stem cells are genetically identical to the patient's cells, so the immune system will not recognize them as foreign. Of course, therapeutic cloning (human cloning for the purpose of obtaining embryonic stem cells) would solve the problem of tissue rejection using embryonic stem cells. However, even if therapeutic cloning becomes scientifically and politically possible, treatment with adult stem cells (if feasible) seems like an easier approach. -
stems cells vs pharmacists
Yggdrasil replied to Ice-cream's topic in Biochemistry and Molecular Biology
I think the development of stem cells will help pharmacists. With stem cells, researchers will have access to genetically identical cultures of various cell types upon which they can conduct more highly controlled pharmacological experiments. Plus, research into stem cells will undoubtedly bring great advances into our understanding of developmental processes which help identify new pharmaceuticals to treat abnormal developmental processes (i.e. cancer). I do not think that stem cells will replace drugs. As stem cell technologies develop, they will be very expensive. Therefore, drugs will likely be the method of choice for treating routine symptoms. Stem cell therapy will likely be reserved for only those cases where drugs cannot effectively address the problem. -
When K = 1, there will be equal concentrations of products and reactants at equilibirum. In terms of thermodynamics, this corresponds to a reaction with no change in Gibbs free energy ([math]\Delta G = 0[/math]). The terms carbocation and carbanion can refer to both the entire moleculre or the specific carbon.
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Bond order is equal to (the number of electrons in bonding orbitals - the number of electrons in antibonding orbitals)/2. In a diatomic hydrogen molecule, there is one bonding orbital (which holds two electrons) and one antibonding orbital (which holds an additional two electrons). Because the bonding orbital has a lower energy, you fill that one up first before electrons are added into the antibonding orbital. In H2, each hydrogen contributes two electrons which both go into the bonding orbital. The bond order is 1. H2+ is lacking an electron, so its one electron goes into the bonding orbital. The bond order is 1/2. H2- has an extra electron. The first two electrons fill the bonding orbital, so the third goes into the antibonding orbital. The bond order is therefore 1/2 [(2-1)/2]
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Ketones won't under go hydrolysis. You're right that all carboxylic acid derivatives can undergo hydrolysis. This is because carboxylic acid derivatives are synthesized through a dehydration reaction with another compound. The reverse reaction (hydrolysis) converts the derivative back into a carboxylic acid. Carboxylic acids won't undergo hydrolysis because if you hydrolyze a carboxylic acid, you get the same carboxylic acid.
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Maxwell's equations predict that electromagnetic waves (i.e. light) in a vacuum must have a certain speed of propagation, defined by the permittivity of free space and permeaility of free space. Einstein reasoned that since Maxwell's equations must be valid in all inertial frames of reference, light must propagate at the same speed in every inertial frame of reference, and after a few thought experiments, he came to the conclusion that nothing could go faster than the speed of light.
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There are only three bonds to the carbon in the diagram, not four. This may seem weird, since for carbon to have a full octet it needs four bonds, but it is possible to have a carbon atom without a full octet. Carbon 1 is what is known as a carbocation, an electron-defficient carbon. If you take organic chemistry, you'll see a lot of reactions involving carbocation intermediates.
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The answer is v. A carbon has four valence electrons, so when carbon has four electrons, it has a formal charge of 0. Carbon 1 has three bonds and no lone pairs giving it three electrons and thus a formal charge of +1 (less electrons, means more positive charge). Carbons 2 and 3 have four bonds, giving it 4 electrons and no formal charge. Oxygen atoms have six valence electrons, and oxygen 4 has one bond and three lone pairs giving it a total of 7 electrons (1 from the bond, and 6 from the lone pairs). Thus, the oxygen has a formal charge of -1.
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HELP WITH COURSEWORK . . .NOW (on enzymes and activation energy)
Yggdrasil replied to Cloud's topic in Homework Help
To understand this question, you need to understand not just the chemistry (all you wrote about the 10-degree rule is correct), but the biochemistry as well (this part is missing in your explanation). The 10-degree rule does not generally apply to reactions catalyzed by biological catalysts. Why? Enzymes are proteins with highly ordered three dimensional structures. Enzymatic catalysis depends upon the highly orderd structure of the molecule. These structures are held together by a wide variety of intramolecular forces ranging from very strong covalent interactions (such as disulfide bonds) to weaker interactions (such as hydrogen bonds or van der waals forces). So, in answering the question, you need to also think of the effects that raising the temperature would have on the catalyst. -
Organisms use enzymes to catalyze esterifications. Enzyme catalysis allows them to carry out the reactions out at low temperatures and physiological pH rather than at high tempreratures and low pH. Regarding organic acids: theoretically, salicylic acid should be easy produce from aspirin (acetlysalicylic acid). If you grind up comercial aspirin, you should be able to extract the asprin in a suitable organic solvent (isopropanol may work) or base-treated water. The aspirin can be converted to salicylic acid by heating in a strong solution of aqueous base (e.g. NaOH). This will give a mixture of salicylic acid and acetic acid (vinegar). The salicylic acid can be purified by cooling the reaction mixture and adding a cold solution of a weak inorganic acid (e.g. dilute (~5%) HCl or dilute phosphoric acid). The salicylic acid should precipiate (if not, try adding salt to the mixture). The salicylic acid can then be used for an esterification. For example, if methanol and salicylic acid are esterified, they produce methyl salicylate (oil of wintergreen). Since aspirin is an organic acid and is very similar to salicylic acid, a wintergreen-smelling ester could possibly be produced just by esterifying methanol and aspirin. Note: I have not tried any of these reactions, so I don't know for sure if they will work. This is just here for anyone who would like to give it a shot.
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Females are generally considered to be the ones who "create" new life, since human females are the ones who give birth to children. Since the daughter cells will eventually divide and create new "progeny," by the simplistic definition of gender above, they must be female.
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Ideally, you would perform an esterification with sulfuric acid. The presence of water in the initial reaction mixture will decrease yields (because it shifts the equilibrium toward the products), so adding sulfuric acid helps to eliminate water and increase yields. If you do decide to do an esterification, here are some compounds and the fragrance they produce: Isoamyl acetate - banana oil Ethyl butyrate - pineapple Isobutyl propionate - rum Octyl acetate - orange Methyl anthranilate - grape Isopentenyl acetate - "Juicy Fruit" benzyl acetate - peach n-propyl acetate - pear methyl butyrate - apple ethly phenylacetate - honey methyl salicylate - oil of wintergreen 2-phenyl ethyl propionate - lily flower
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The difference in solubility paterns can be explained using thermodynamics. First, here is a simple explanation: In general, processes tend to go toward increasing entropy (disorder) at high temperatures even at the expense of creating a high energy (unstable) system. The opposite is true at low temperatures; processes tend to go toward decreasing enthalpy (potential energy/stability) even at the expense of becomming more ordered. For a solid disolving in water, entropy is increasing since the water breaks up the highly ordered crystal latice of the solid. However, breaking the intramolecular bonds holding the solid together increases the potential energy of the aqueous (disolved) solution. Therefore at high temperatures, the aqueous (more disordered) state is more favorable while the solid (lower energy) state is favored more at low temperatures. The opposite is true of gasses. Gasses are much more disordered in the gas state than in the aqueous state. However, they are in a lower energy state in the aqueous phase. So in order to make the aqueous state more favorable, one should decrease the temperature in order to keep it in the lower energy aqueous phase. In mathematical terms, this principle is reflected in the equation: [math]\Delta G = \Delta H -T \Delta S[/math] As the change in free energy [math]\Delta G[/math] decreases, a process becomes more favorable. Therefore, for a positive change in entropy,([math]\Delta S > 0[/math]), the process becomes more favorable as temperature increases. For a negative change in entropy, ([math]\Delta S < 0[/math]), the process becomes more favorable as temperature decreases.
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Yes. The easiest explanation is that of recessive traits, which causes a mutant phenotype (trait) only when a someone possesses two mutant alleles. For example, consider the heritable disease, cystic fibrosis. Let's call the wild type (normal) allele C and the mutant (disease) allele c. If a woman who has the geneotype Cc marries a man with genotype Cc, netiher parent has cystic fibrosis since they both have one dominant wild type allele. But they could have a child with genotype cc, who would have cystic fibrosis even though neither parent had cystic fibrosis. Of course, in the case of aptitude for computer science, it's unlikely that genes control that trait at all; it's likely the result of environmental factors (upbringing, education, etc.) primarily.
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His tagged protein folding - Confused -Please help
Yggdrasil replied to KLIK's topic in Biochemistry and Molecular Biology
It is not always possible to refold a protein when it is purified under denaturing conditions. If you don't have access to an NMR machine, you could try obtaining a CD (circular dichroism) spectrum since that can provide a good enough assessment of whether your protein is correctly folded. If dialyzying the urea out of the eluant doesn't correctly fold your protein, you could try refolding the protien on the Ni column. After binding the protein to the column, wash with progressively lower concentrations of urea. Then was with buffer containing no urea and elute in a buffer containing no urea.