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One argument put forward has been that aluminum is very poorly bioavailable, moreso than many other elements. Aluminum oxide is very insoluble in water. In addition, any dissolved aluminum that does form in seawater is likely to be precipitated by silicic acid, forming hydroxyaluminosilicates. From Chris Exeter's 2009 article in Trends in Biochemical ...


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The metal’s trivalency is certainly not an issue. Iron and cobalt form trivalent compounds (in the $\mathrm{+III}$ oxidation state) in many of their biologically relevant complexes. In fact, in metalloprotein surroundings the actual ‘valency’ (oxidation state) is not so much of a deciding factor; what matters is the number of ligands and the required ...


3

Are all the biochemicals that our body uses enantiomerically pure or are racemic mixtures too? Many molecules exist in both forms in nature. One fun example are the enantiomeric terpenoids R-(–)-carvone and S-(+)-carvone. The R-form smells like spearmint while the S-form smells like caraway. The difference in smell shows that properties other than the ...


3

You need to know which acids are present in the sample, or determine the required amount experimentally. Without any knowledge of the pKa values of the acid or acids present, there could be very different scenarios. A pH of about 5 could be due to a high concentration of a weaker acid or a low concentration of a stronger acid. For example, 0.01 mM of HCl ...


3

Horseradish peroxidase is not hydrogen peroxide, $\ce{H2O2}$, but rather an enzyme that breaks $\ce{H2O2}$ into $\ce{H2O}$ and $\ce{O2}$. In general, enzymes ending in -ase are lytic enzymes, catalyzing the breakdown of a similar-sounding substance. So, if you add ground horseradish to hydrogen peroxide, bubbles of oxygen are released. BTW, horseradish roots ...


2

$\ce{H2O2}$ is Selective The reason why hydrogen peroxide can be used for such diverse applications is the different ways in which its power can be directed -- termed selectivity. By simply adjusting the conditions of the reaction (e.g., $\mathrm{pH}$, temperature, dose, reaction time, and/or catalyst addition), $\ce{H2O2}$ can often be made to oxidize one ...


1

The pH is not corrected mathematically, it is stabilized chemically by addition of NaOH when the pH sensors get out of range. Your pH is controlled to be constant over the fermentation period (+/- a little bit). The acid produced by the fermentation is neutralized by addition of NaOH to keep the pH constant. What you can calculate from the data you get is ...


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