21) Coupled reactions are:

A) reactions in which endergonic reactions obtain the energy to go forward from exergonic reactions.

B) reactions in which exergonic reactions obtain the energy to go forward from endergonic reactions.

C) any reactions that are accelerated by an enzyme.

D) reactions that lower the activation energy of another reaction.

22) The energy released during ________ reactions can be used to drive ________ reactions, and this is called ________ reactions.

A) endergonic; exergonic; coupled

B) exergonic; endergonic; coupled

C) endergonic; exergonic; mutually dependent

D) exergonic; endergonic; mutually dependent

23) What is the energy currency of cells?

A) ATP

B) glucose

C) enzymes

D) ADP

E) vitamins

24) In the ATP/ADP cycle:

A) food provides the energy needed to link phosphate to ADP to make ATP.

B) food provides the energy needed to break down ATP into ADP.

C) converting ADP into ATP is an energy-yielding reaction, whereas converting ATP into ADP is an energy-requiring reaction.

D) after powering a reaction, ADP becomes ATP.

25) The structure of ATP includes each of the following except:

A) the nitrogenous base adenosine.

B) the sugar ribose.

C) the nitrogenous base adenine.

D) phosphate groups.

26) In the following reaction, which of the following is an example of a substrate?

    Lactase

Lactose→Glucose + Galactose

A) galactose

B) glucose

C) lactose

D) lactase

27) The substance that is worked on by an enzyme is called:

A) product.

B) coenzyme.

C) inhibitor.

D) substrate.

28) You have a friend who tells you she is lactose intolerant. She asks you to explain what this means. You say to her:

A) “You cannot digest milk because you cannot absorb it in your intestines.”

B) “You are allergic to milk.”

C) “You cannot digest milk because you do not have the enzyme to break down the sugar in the milk.”

D) “You cannot digest the milk because you do not have the enzyme to break down the protein in the milk.”

E) “You cannot digest the milk because you do not have the enzyme to break down the lipid in the milk.”

29) The diversity of chemical reactions occurring in a cell depends mostly on certain molecules present in the cells, which are called:

A) enzymes.

B) proteins.

C) cofactors.

D) coenzymes.

E) ribozymes.

30) In a ________, multiple enzymes are working together in a multistep process.

A) feedback loop

B) coupled reaction

C) allosteric pathway

D) metabolic pathway