CHEM150 CH6-8

Where do allosteric effectors bind on an enzyme?

• They always bind at the catalytic site.

• They always bind at a site different from the catalytic site.

• They can bind at either the catalytic site or at a different site.

In the induced-fit model of substrate binding to enzymes, what happens?

• There is a conformational change of the catalytic site when the substrate binds.

• There is aggregation of several enzyme molecules when the substrate binds.

• The substrate changes its conformation to fit inside the catalytic site.

What is the main thermodynamics-related difference between a catalyzed and a non-catalyzed reaction?

• Both activation energy and net free energy change are null for the catalyzed reaction.

• The activation energy change of the catalyzed reaction is the lowest of the 2 reactions.

• The net free energy change of the catalyzed reaction is the lowest of the 2 reactions.

Which of the following is true?

• Allosteric enzymes are rarely important in the regulation of metabolic pathways.

• Michaelis-Menten kinetics model the mechanism of allosteric enzymes.

• An hyperbolic representation of the relation initial velocity vs [S] is a specific characteristic of an allosteric enzyme's behavior.

• None of these is true.

Is hindrate a competitive inhibitor, irreversible inhibitor, or noncompetitive inhibitor?

• Competitive inhibitor

• Irreversible inhibitor

• Noncompetitive inhibitor

Which of the following types of inhibitor binds reversibly to the enzyme at the same site as the substrate without altering the overall enzyme structure?

• Noncompetitive inhibitor

• Competitive inhibitor

• Irreversible inhibitor

What does amphipathic mean?

• Having both positive and negative charges.

• Having both acid and base properties.

• Having both hydrophilic and hydrophobic regions.

• Having two stereoisomers.

Which of the following moieties is not present in a molecule of triacylglycerol?

• Phosphate

• Fatty acid

• Glycerol

Which of the following modes of transport is spontaneous?

• Primary active transport

• Facilitated diffusion

• Secondary active transport

Which of the following modes of transport across a membrane requires bio-energy?

• Passive transport

• Facilitated transport

• Active transport

• Simple diffusion