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

3. In mitochondrial electron transport, what is the direct role of O2? (A)to provide the driving force for the synthesis of ATP from ADP and Pi (B)to oxidize NADH and FADH2 from glycolysis, acetyl CoA formation, and the citric acid cycle (C)to provide the driving force for the production of a proton gradient (D)to function as the final electron acceptor in the electron transport chain (E)to provide electrons

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

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.

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