8. The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the
(A)H+ concentration gradient across the membrane holding ATP synthase.
(B)flow of electrons down the electron transport chain.
(C)transfer of phosphate to ADP.
(D)oxidation of glucose and other organic compounds.
(E)electron transmission of photosynthesis.

4. Imagine protein X, destined to span the plasma membrane； assume the mRNA carrying the genetic message for protein X has been translated by ribosomes in a cell culture. If you fractionate the cells, in which fraction would you find protein X? (A)pellet rich in nuclei and cellular debris (B)pellet rich in "microsomes" (C)pellet rich in mitochondria (D)pellet rich in ribosomes (E)pellet rich in microtubules

5. Which cell would be best for studying lysosomes? (A)bacterial cell (B)phagocytic white blood cell (C)muscle cell (D)nerve cell (E)fibroblast

6. Consider this pathway: epinephrine → G protein‐coupled receptor → G protein → adenylyl cyclase → cAMP. Identify the second messenger. (A)adenylyl cyclase (B)G protein (C)cAMP (D)GTP (E)dATP

7. Which of the following occurs during apoptosis? (A)release of proteases outside the cell (B)lysis of the cell (C)direct contact between signaling cells (D)fragmentation of the DNA (E)DNA replication

9. Which of the following sequences correctly represents the flow of electrons during photosynthesis? (A)NADPH→ O2→ CO2 (B)NADPH→ electron transport chain→ O2 (C)H2O→ NADPH→ Calvin cycle (D)H2O→ photosystem I→ photosystem II (E)H2O→ mitochondria→ NADPH

10. In mechanism, photophosphorylation is most similar to _______ (A)carbon fixation. (B)oxidative phosphorylation in cellular respiration. (C)substrate‐level phosphorylation in glycolysis. (D)reduction of NADP+. (E)protein synthesis and modification

11. Which of the following is a true statement? (A)Anabolic pathways build molecules, require energy, and are endergonic. (B)Catabolic pathways build molecules, release energy, and are exergonic. (C)Catabolic pathways break down molecules, require energy, and are exergonic. (D)Anabolic pathways break down molecules, require energy, and are endergonic. (E)The second and third answers are correct.

12. In the cell cycle, which of the following occurs during S phase? (A)separation of sister chromatids (B)replication of the DNA (C)spindle formation (D)condensation of the chromosomes (E)centrosomes synthesis

13. Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle? (A)M (B)G1 (C)G2 (D)S (E)cytokinesis

14. Asexual reproduction __________. (A)is limited to plants (B)requires both meiosis and mitosis (C)leads to a loss of genetic material (D)is limited to single‐cell organisms (E)produces offspring genetically identical to the parent