New answers tagged biochemistry
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Use tissue preparation for optical microscopy, which preserves fine detail of the specimen. The general procedure is to pass the tissue through a series of baths, gradually replacing water with a miscible solvent such as alcohol, then replacing the alcohol with a solvent miscible with the alcohol and with paraffin wax or other embedding material. The use of ...
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[...] What is the major source [of ketoses and aldoses?]
Carbohydrates are made in large quantities by photosynthetic organisms like most plants and some microorganisms. The starting materials are carbon dioxide and water, and elemental oxygen is a side product. Some sugars are very common (D-glucose, D-fructose, D-ribose), while others are rare (https://...
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Radioactivity is a very specific type of radiation
Radiation is a very broad term. Usually it means electromagnetic radiation which includes everything from long wavelength radiowaves to hard gamma rays. If we are going with the even more general usage of the word we would also include the particlulate "radiation" often associated with radioactivity.
...
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Osmotic flow is the movement of a substance (typically water), across a semi-permeable membrane, from the side on which the chemical potential of the substance (water) is higher to the side on which it is lower. I.e., just as temperature provides a gradient for the flow of thermal energy, chemical potential provides a gradient for the flow of matter.
Thus ...
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Application of the Michaelis-Menten equation generally assumes steady state concentration of the enzymatic complex intermediate. Then $K_M$ allows two interpretations$^1$:
an apparent dissociation constant describing the equilibrium $$\ce{ES<=>E +S}\tag{1}$$
where $E$ and $S$ are the concentrations of enzyme and substrate, respectively
the ...
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The Michaelis–Menten kinetics model formula is:
$$ V= \frac{(d¦P¦)}{dt} = \frac{(Vmax)¦S¦}{Km + ¦S¦}$$
Reaction rate V is the rate of formation of product, ¦P¦ is the concentration of product and the ¦S¦ the concentration of a substrate S.
In a saturated regime V = Vmax and this occours only if:
$$ \frac{¦S¦}{Km + ¦S¦} \approx 1 $$
This is nearly equal to ...
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According to https://www.uniprot.org/uniprot/P25325, 3-mercaptopyruvate sulfurtransferase is also involved in the catabolism of cysteine:
Transfer of a sulfur ion to cyanide or to other thiol compounds. Also has weak rhodanese activity. Detoxifies cyanide and is required for thiosulfate biosynthesis. Acts as an antioxidant. In combination with cysteine ...
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Cysteine is a dispensable amino acid required for synthesis of protein and non-protein compounds. These non-protein compounds include pyruate (hence acetyl coenzyme A), taurine, sulfate, and glutatione (GSH). The fate of the cycteine is hence sketched in following diagram (Ref.1):
As evidence from the diagram, the sulfur atom in cysteine has been converted ...
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Most alkaloids are tertiary amines. Almost all tests for alkaloids, reagents of which are are solutions of the salts of heavy metals, are precipitation tests. For example, all of tests with Dragendorff's reagent, Mayer's reagent, Hager's reagent, and Wagner's reagent give color precipitates: The heavy metal atom in the reagent with the nitrogen in the ...
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The obvious approach to is to just do the direct analog of what Earthling metabolism does: exactly reverse the photosynthetic reaction (on net, anyway; the intermediate processes may be rather different, as they are on Earth).
In this case, that means reacting hydrogen with carbohydrates to get back methane and water. Based on this paper on photosynthesis ...
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This is only a partial answer, but maybe will stimulate some thinking by others.
For a good sense of plausible reactions, one need only look at the existing biology of anaerobic organisms. Many organisms produce energy in the absence of oxygen, either by fermentation or anaerobic respiration (the distinction being the absence or presence of an energy-...
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