Cell Biology: Enzymes

What is the role of the transition state in a biochemical reaction?

• The transition state is the final product of the reaction.
• The transition state is an intermediate condition where reactants are at a high-energy state.

• The transition state increases the activation energy required for the reaction.
• The transition state is a stable intermediate that does not change during the reaction.

Tags

NGSS.HS-PS1-5

Which of the following best describes activation energy (AE)?

• The total energy of the reactants in a chemical reaction.
• The minimum energy required for a chemical reaction to occur.
• The energy required to break chemical bonds only.
• The energy released during a chemical reaction.

Tags

NGSS.HS-PS1-5

What distinguishes a coenzyme from a cofactor?

• Coenzymes are organic molecules, while cofactors are often inorganic ions.

• Cofactors are only found in enzymes, while coenzymes are not.
• Coenzymes are larger molecules than cofactors.
• A coenzyme is always inorganic, while a cofactor is organic.

What is a zymogen?

• A zymogen is a protein that speeds up reactions.
• A zymogen is a type of hormone.
• A zymogen is a substrate that binds to the active site.

• A zymogen is an inactive form of an enzyme that requires activation.

Which of the following statements about enzymes is true?

• Enzymes are consumed in reactions and cannot be reused.

• Enzymes increase the rate of a reaction by a factor of 10 to 100.

• Enzymes lower the activation energy required for reactions.

• Enzymes alter the equilibrium point of reactions.

Tags

NGSS.HS-PS1-5

Which type of inhibitor increases the apparent Km without affecting Vmax?

• Competitive inhibitor
• Irreversible inhibitor
• Uncompetitive inhibitor
• Non-competitive inhibitor

In the induced fit model, what occurs upon substrate binding?

• The enzyme releases the substrate immediately upon binding.
• The enzyme denatures completely.

• The enzyme becomes inactive upon substrate binding.
• The enzyme changes shape to better accommodate the substrate.

Which of the following is a prosthetic group?

• Myoglobin
• Magnesium ions

• NAD⁺

• Heme

What is the Michaelis constant (Km)?

• The substrate concentration at which the reaction rate is maximum.

• The maximum rate of an enzyme-catalyzed reaction.

• The substrate concentration at which the reaction rate is half of Vmax.

• The energy required to reach the transition state.

How does temperature affect enzyme activity?

• Enzymes are not affected by temperature changes.
• Temperature affects enzyme activity by increasing it up to an optimal point, after which activity decreases due to denaturation.
• Higher temperatures increase enzyme activity.

• Temperature has no effect on enzyme activity.