Review Questions

For each question, choose the ONE BEST answer or completion.

1. A reaction that has a positive AG will

A. proceed, although the rate may be very slow in the absence of an enzyme.

B. only proceed in the presence of an enzyme.

C. generate water.

D. not proceed, even if an enzyme is present.

E. be coupled to a carrier.

2. Which of the following is not a cellular energy currency?

A. The sodium gradient across the plasma membrane

B. Glucose

D. NADH

E. The H+gradient across the mitochondrial inner membrane

3. Which of these statements about the proteins responsible for converting between the four energy currencies is not correct?

A. They are all reversible.

B. They are all located on the mitochondrial inner membrane.

C. Drugs that block them are highly toxic.

D. They are all carriers.

E. None of the above are true.

4. Hydrogen ions that enter the mitochondrial matrix through ATP synthase release a lot of energy because

A. the mitochondrial matrix is electrically negative with respect to the cytosol.

B. H+ is at a higher concentration in the mitochondrial matrix than in the cytosol.

C. the mitochondrial inner membrane contains thermogenin.

D. H+ is at a higher concentration in the cytosol than in the mitochondrial matrix.

E. There is a large electrochemical gradient favoring H+ entry.

5. The overall reaction catalyzed by the electron transport chain is

A. Glucose + ATP ^ Glucose-6-phosphate + ADP

6. Which of the following statements is incorrect?

A. Mitochondria may have been derived in evolution from a prokaryote.

B. Mitochondria have their own DNA.

C. Mitochondria have a large negative voltage across their inner membrane.

D. Mitochondria increase their generation of ATP in cells starved of oxygen.

E. Mitochondria generate NADH.

7. The electron transport chain in mitochondria

A. accepts electrons from NADH, thus oxidizing it to NAD+.

B. passes electrons to oxygen, thus reducing it to water.

C. uses the hydrophobic molecule ubiquinone to carry electrons between integral membrane protein complexes.

D. uses the hydrophilic molecule cytochrome c to carry electrons between integral membrane protein complexes.

E. all of the above.

Was this article helpful?

0 0

Post a comment