Enzyme C1.11-17 HL only

Which of the following is an example of an intracellular enzyme-catalyzed reaction?

• The breakdown of food in the stomach

• The reaction of oxygen and glucose in the lungs

• The breakdown of glucose in glycolysis

• The synthesis of protein in the ribosomes

If metabolic reactions were 100% efficient in energy transfer, what would be the most likely consequence?

• There would be no need for mammals and birds to eat

• Heat generation by metabolic reactions would increase

• Heat generation by metabolic reactions would be eliminated

• All metabolic reactions would occur at the same rate

Which of the following best describes the difference between cyclical and linear pathways in metabolism?

• Cyclical pathways, like the Krebs cycle, are a series of reactions where the final product is the initial reactant, while linear pathways, like glycolysis, are a series of reactions that proceed in a stepwise manner

• Cyclical pathways, like glycolysis, are a series of reactions that proceed in a stepwise manner, while linear pathways, like the Krebs cycle, are a series of reactions where the final product is the initial reactant

• Cyclical pathways, like glycolysis, involve reactions that repeat in a cycle, while linear pathways, like the Krebs cycle, involve reactions that proceed in a stepwise manner

• Cyclical pathways, like the Krebs cycle, involve reactions that occur in the mitochondria, while linear pathways, like glycolysis, occur in the cytoplasm

What distinguishes non-competitive inhibition from competitive inhibition?

• In non-competitive inhibition, the inhibitor binds to the enzyme's active site, while in competitive inhibition, the inhibitor binds to an allosteric site

• In non-competitive inhibition, the inhibitor binds to an allosteric site on the enzyme, causing a change in the enzyme's shape that prevents substrate binding, while in competitive inhibition, the inhibitor and substrate compete for the enzyme's active site

• In non-competitive inhibition, the inhibitor permanently binds to the enzyme's active site, while in competitive inhibition, the inhibitor's binding is reversible

• In non-competitive inhibition, the inhibitor binds to the substrate, while in competitive inhibition, the inhibitor binds to the enzyme's active site

What is the role of isoleucine in the regulation of metabolic pathways?

• Isoleucine is a product of a metabolic pathway that can act as a competitive inhibitor, binding to the enzyme's active site and preventing substrate binding

• Isoleucine is a product of a metabolic pathway that can act as an allosteric activator, binding to the enzyme and encouraging substrate binding

• Isoleucine is a product of a metabolic pathway that can act as a non-competitive inhibitor, binding to an allosteric site on the enzyme and preventing substrate binding

• Isoleucine is a product of a metabolic pathway that can act as a feedback inhibitor, binding to the enzyme and decreasing the pathway's activity when isoleucine levels are high

Which of the following reactions release free energy?

• Exergonic reactions

• Endergonic reactions

• Both of the above

• None of the above

What is the consequence of metabolic reactions not being 100% efficient?

• There is no consequence

• They generate heat

• They do not generate heat

• They are 100% efficient

What are endotherms?

• Animals that cannot control their cell metabolism

• Animals that depend on heat production for maintenance of body temperature

• Animals that do not generate heat in metabolic reactions

• Animals that do not depend on heat production for maintenance of body temperature

What are ectotherms?

• Animals that depend on heat production for maintenance of body temperature

• Animals that do not generate heat in metabolic reactions

• Animals that cannot control their cell metabolism

• Animals that generate heat in metabolic reactions

Which of the following reactions absorb energy?

• Exergonic reactions

• Endergonic reactions

• Both of the above

• None of the above