42 votes
Accepted

Do photosynthesis and respiration violate the law of conservation of energy?

With slight adjustments to the scientific wording, what the poster states is in effect: “…to produce one molecule of glucose in photosynthesis, 18 ATP molecules are used up hydrolysed” and “…...
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20 votes
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Why is protein turnover necessary or important for cells to function?

Biology is an intricate orchestration of chemical reactions and their products. Generally, this fete is accomplished by enzymatic facilitation of certain reactions that would otherwise occur too ...
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7 votes

Why is protein turnover necessary or important for cells to function?

Many aspects of cellular function are related to feedbacks and cycles wherein proteins need to fluctuate in abundance to maintain cellular function. One example of protein cycling would be cell cycle ...
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7 votes

Why isn't the Ramachandran plot symmetric?

It's awkward answering your own question, but I think I have now realized where my misconception arose from. If we look at the 3 dimensional structure of a protein and consider the third alpha carbon ...
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  • 149
7 votes

Why isn't the Ramachandran plot symmetric?

but only the Ramachandran plot for glycine shows this symmetry With the exception of glycine, all the common amino acids exhibit chirality at the carbon atom adjacent to the carboxyl group. Except ...
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2 votes

When forming an enzyme-substrate complex in a spontaneous reaction, why does free energy increase?

Kinetics and thermodynamics are two separate things. The type of diagram you show is often encountered (even in textbooks) because it is thought to be a convenient hand-weaving way to convey a feeling ...
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  • 163
2 votes
Accepted

How to reduce PPi concentration in blood samples by PPase

Bernhard et al. 1 describe a method for the treatment of human plasma with yeast inorganic pyrophosphatase. The PPase-treated plasma is used as both a diluent and a negative control in their PPi ...
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1 vote

Are there irreversible metabolic reactions that can happen in opposite ways depending on the cellular conditions?

Reversibility of biochemical reactions The general view of the way “irreversibility” is regarded in biochemistry is well summarized by the respected enzymologist, Athel Cornish-Bowden: “...
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