NURSING EXAM QUESTIONS
BIOCHEMISTRY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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acidic only
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basic only
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neutral
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sometimes acidic, sometimes basic
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Detailed explanation-1: -A low pH (1.5 to 2) activates pepsin. Acetylcholine, gastrin, and histamine stimulate the proton pump in parietal cells to release hydrogen ions and decrease pH.
Detailed explanation-2: -Pepsin, the first animal enzyme discovered (Florkin, 1957), is an acidic protease that catalyzes the breakdown of proteins into peptides in the stomach, while it does not digest the body’s own proteins.
Detailed explanation-3: -Pepsin hydrolyses proteins into short polypeptides in an acidic medium of pH 2.0 in the stomach.
Detailed explanation-4: -The reason pepsin functions best at pH 2 is because the carboxylic acid group on the amino acid in the enzyme’s active site must be in its protonated state, meaning bound to a hydrogen atom. At low pH the carboxylic acid group is protonated, which allows it to catalyze the chemical reaction of breaking chemical bonds.