Question

question 10
1 pts
which of the following is not true about enzymes:
they increase δg of reactions.
they are usually made of amino acids.
they lower the activation energy of chemical reactions.
each one is specific to the particular substrate(s) to which it binds.
none of these answer choices are correct.
question 11
1 pts
an allosteric inhibitor does which of the following?
binds to an enzyme away from the active site and changes the conformation of the active site, increasing its affinity for substrate binding.
binds to the active site and blocks it from binding substrate.
binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate.
binds directly to the active site and mimics the substrate.
none of these answer choices are correct.
question 12
1 pts
which of the following analogies best describes the induced - fit model of enzyme - substrate binding?
a hug between two people
a key fitting into a lock
a square peg fitting through the square hole and a round peg fitting through the round hole of a childrens toy
the fitting together of two jigsaw puzzle pieces
none of these answer choices are correct.

Explanation:

• Question 10: Enzymes are biological catalysts. They lower the activation - energy of reactions, are usually proteins (made of amino acids), and are specific to their substrates. They do not change the $\Delta G$ of a reaction. $\Delta G$ is a measure of the free - energy change of a reaction and is independent of the presence of an enzyme.
• Question 11: An allosteric inhibitor binds to an enzyme at a site other than the active site (allosteric site). This binding causes a conformational change in the active site that decreases its affinity for the substrate, inhibiting the enzyme's activity.
• Question 12: The induced - fit model of enzyme - substrate binding suggests that the enzyme's active site is not a rigid structure but rather undergoes a conformational change upon binding to the substrate, much like a hug between two people where both parties adjust to fit each other. The other analogies (key - lock, peg - hole, jigsaw pieces) represent the lock - and - key model where the enzyme and substrate have pre - formed complementary shapes.

Answer:

Question 10: They increase $\Delta G$ of reactions.
Question 11: Binds to an enzyme away from the active site and changes the conformation of the active site, decreasing its affinity for the substrate.
Question 12: a hug between two people