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1.Why are they carcinogenic: From my point of view as a medicinal chemist, polycyclic aromatic hydrocarbons compounds tend to be metabolized by specific cytochrome P450 (CYP 450) isofroms to form highly electrophilic species, which are highly reactive and can react with the DNA of the cell and damage it. Specifically, they can react with the nucleophilic ...


5

Osmotic pressure for non-electrolytic solutes is given by $$\pi = CRT$$ where $C$ is the effective concentration of all the solutes. In our case, with multiple solutes, we simply add all their concentrations to obtain the effective concentration. This gives us $$ \begin{align} \pi_\mathrm{cell} &= 0.05RT\\ \pi_\mathrm{environment} &= 0.03RT \end{...


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A double bond between 2 carbon atoms means there is a $\pi$ bond with the side orbital overlaps in 1 plane, in parallel to the axial $\sigma$ bond. The consequence is, free rotation would need to break this $\pi$ bond, making the double bond just a single bond, what would require a strong torque and a lot of energy. A non chemical analogy can be like ...


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A large percentage of pharmaceuticals are sold as salts, and sometimes even as co-crystals, i.e. a drug cation and a drug anion. You are right in the sense that the basic purpose is to make them soluble but this is not the only one. If it is a intravenous drug, salt form may have less pain. A low molecular weight medicine might be in a liquid form yet its ...


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Thiamine (Vitamin B1) has a positive charge on the nitrogen of thiazole ring, because that nitrogen is tetravalent. Thus, it should be neutralized by a counter ion. Usually, the counter ion is chloride ($\ce{Cl-}$) ion. Over-the-counter Vitamin B1 usually supplies as hydrochloride salt of thiamine chloride (simply called thiamine hydrochloride), which is ...


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There is a crystal structure of human gastric lipase (PDB ID 1hlg). The accompanying paper does not mention any quaternary structure and shows the protein as single chain. Automated analysis of the coordinates support that. The enzyme is glycosylated, so the molar mass does not match the one expected from the sequence. The apparent molar mass determined ...


2

If we call the drug L, and the binding sites S, the equilibrium is the following: $$\ce{LS <=> L + S}$$ The equilibrium constant expression is: $$K_d = \frac{[\ce{L}] [\ce{S}]}{[\ce{LS}]}$$ With $[\ce{L}]_\mathrm{tot}$ as the total concentration of ligand and $[\ce{S}]_\mathrm{tot}$ the total concentration of binding sites, we can solve of $[\ce{L}]...


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I get that oxygen is the terminal electron acceptor in oxidative phosphorylation. But why is it essential to accept these electrons and remove them as H2O? A redox reaction is made of two half reactions. Neither one of them is more or less important; the combination of both determines the energetics of the reaction. Why is having an efficient garbage ...


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There are fuel cells that run on alcohols such as ethanol or methanol and on glucose. That said, the energy density in current Li-ion cells is quite high - a 18650 cell holds ~30,000 joules, about 9 kCal. By comparison, a "biochemically" powered shotgun shell (well, the nitrate and carbon of gunpowder can come from bio sources) packs ~2,000 J.


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Oxidative phosphorylation consists of electron transport chain and chemiosmosis. During electron transport chain, electrons transfer causes the energy production and forms an electrochemical gradient. Then, during chemiosmosis, the energy produced during this electrochemical gradient is used to synthesize ATP. So, why oxygen is needed in electron transport ...


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Allosteric inhibitors changes the conformation of enzyme enzyme for preventing the substrate binding, and allosteric activators modify the enzyme conformation so that substrate binding can take place. Competitive inhibitors don't change the enzyme conformation, as these inhibitors compete with the substrate to bind at enzyme's active site. Non-...


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