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

80. 30 歲女性病人有心臟瓣膜疾病史，近來總是覺得疲累、夜間會突然醒來且心跳加速。於心尖處聽診到一個柔軟、高頻率的收縮期心雜音，下列何者為最可能之診斷？(A) 主動脈瓣逆流 ( aortic regurgitation ) (B) 主動脈瓣狹窄 ( aortic stenosis ) (C) 二尖瓣逆流 ( mitral regurgitation ) (D) 二尖瓣狹窄 ( mitral stenosis )

1. Variation in carbon chains is an important source of molecular complexity. How can carbon skeletons vary? (A)Carbon skeletons can vary in length and contain rings of carbon atoms (B)Carbon skeletons can vary in length, exhibit different branching structures, contain double bonds at different positions, and contain rings of carbon atoms (C)Carbon skeletons only vary in length (D)Carbon skeletons can vary in length and contain double bonds at different positions (E)Carbon skeletons can vary in length and exhibit different branching structures

2. A cell has formed a food vacuole as it ingested a food particle. Which of the following events is associated with the breakdown of that food particle? (A)enzymes for the breakdown of the food are delivered to the food vacuole from the cytosol (B)proteins for digestion of the food particle were initially processed in mitochondria (C)proteins for digestion of the food are made by ribosomes in the Golgi apparatus (D)the membrane of the food vacuole is derived from the cell wall (E)digestion of the food particle occurs in a vesicle enclosed by a membrane that separates the digestion from the cytoplasm

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

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

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