GRE Subject Test: Biochemistry, Cell, and Molecular Biology : Macromolecules and Enzymes

Study concepts, example questions & explanations for GRE Subject Test: Biochemistry, Cell, and Molecular Biology

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All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources

1 Diagnostic Test 201 Practice Tests Question of the Day Flashcards Learn by Concept

Example Questions

Example Question #5 : Enzyme Regulation

How does a noncomeptitive inhibitor affect an enzyme?

Possible Answers:

Raises the Michaelis constant of the enzyme

Lowers the maximum rate of the enzymatic reaction

Raises the maximum rate of the enzymatic reaction

Lowers the Michaelis constant of the enzyme

Correct answer:

Lowers the maximum rate of the enzymatic reaction

Explanation:

A noncompetitive inhibitor acts to decrease how fast the enzyme can act on substrates. It accomplishes this by lowering the maximum rate at which it can create products. Noncompetitive inhibitors do not alter the enzyme's Michaelis constant.

Example Question #6 : Enzyme Regulation

How is pepsinogen activated in the stomach?

Possible Answers:

It is phosphorylated by another enzyme

It is activated by the temperature change in the stomach lumen

Cofactors bind to the enzyme, increasing its efficiency

A portion is cleaved, activating the enzyme

Correct answer:

A portion is cleaved, activating the enzyme

Explanation:

Once in the stomach lumen, pepsinogen finds itself in a very acidic environment. The acidic environment cleaves an amino acid sequence from pepsinogen, turning it into the active enzyme pepsin. This type of activation causes pepsin to only activate in the stomach lumen where it is needed.

All GRE Subject Test: Biochemistry, Cell, and Molecular Biology Resources

1 Diagnostic Test 201 Practice Tests Question of the Day Flashcards Learn by Concept
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