Fundamentals of Biochemistry PASS: Quiz Buster 2

Which of the following statements is true about enzymes?

• They are always used up in reactions.
• They only catalyze reactions at high temperatures.
• Most enzymes are globular proteins.
• All enzymes are made of RNA.

What is a holoenzyme?

• An enzyme without its cofactor
• A complete, catalytically active enzyme with its bound coenzyme and/or metal ions
• An inactive enzyme
• A protein that acts as a coenzyme

How do enzymes enhance the rate of reactions?

• By increasing the temperature of the reaction
• By increasing the pressure
• By lowering the activation energy
• By changing the equilibrium of the reaction

Which of the following is NOT a reason why biocatalysts are preferred over inorganic catalysts?

• Greater reaction specificity
• Higher reaction rates
• Can function at extreme temperatures
• Capacity for regulation

Which of the following is a class of enzymes?

• Lipases
• Hormones
• Neurotransmitters
• All of the above

What is the transition state in a chemical reaction?

• The stable starting point of the reaction
• The stable end product of the reaction
• The highest energy point during the reaction
• The lowest energy point during the reaction

What is the role of weak interactions in enzyme catalysis?

• They destabilize the substrate.
• They provide energy to the enzyme.
• They optimize interactions in the transition state.
• They reduce enzyme specificity.

Which of the following is NOT a correct description of the active site of an enzyme?

• The region where the substrate binds
• A specific site for coenzyme attachment
• The site where catalysis occurs
• A pocket formed by amino acid residues

In the reaction mechanism of chymotrypsin, what is the role of the catalytic triad?

• To bind the substrate specifically
• To provide structural stability to the enzyme
• To facilitate nucleophilic attack on the peptide bond
• To hydrolyze the peptide bond directly

Which of the following statements about the reaction coordinate diagram is FALSE?

• It shows the energy changes during a reaction
• It indicates the ground state of reactants and products
• It displays the transition state energy
• It is used to determine the equilibrium constant of the reaction