What is the primary role of the TCA cycle in the production of ATP?

1. What is the primary role of the TCA cycle in the production of ATP? • break down glucose • create hydrogen gradient • phosphorylate ADP • transfer electrons from substrates to coenzymes

2. What is the electron transport system’s role in the generation of ATP? • It creates a steep concentration gradient across the inner mitochondrial membrane. • It manufactures 36 ATP. • It facilitates formation of coenzymes. • It prevents substrate-level phosphorylation.

3. How does a decrease in the level of cytoplasmic NAD affect ATP production in mitochondria? • ATP production increases. • ATP production decreases. • Pyruvic acid supplies increase. • Unused glucose molecules allow for production of ATP through other mechanisms.

4. NADH produced by glycolysis in skeletal muscle fibers leads to production of two ATP molecules in mitochondria, but NADH produced by glycolysis in cardiac muscle cells leads to production of three ATP molecules. Why? • a. different systems • b. different pH • c. different intermediaries • d. more efficient enzymes in cardiac muscle

5. Why is oxidative phosphorylation the most important mechanism for generating ATP? • a. It requires less energy than other mechanisms. • b. It requires fewer steps to produce ATP molecules. • c. It produces more than 90% of ATP used by body cells. • d. It allows the release of a tremendous amount of energy.

6. What contributes to the increased amount of urea in blood during the postabsorptive state? • a. protein digestion • b. lipolysis • c. glycolysis • d. glycogenesis

7. What consequence(s) is (are) the result of a dietary deficiency of one or more essential amino acids? • Protein deficiency disease occurs. • The body produces the missing amino acids by amination. • Protein synthesis comes to a halt. • Both A and C are correct.

8. Why are proteins an impractical source of quick energy, a “last ditch” source of energy? • Proteins are more difficult to break apart than are carbohydrates or lipids. • NH4, a by-product of protein catabolism, is toxic. • Protein catabolism threatens homeostasis. • All of the above are correct.

9. Why do athletes in intensive training try to maintain a positive nitrogen balance? • a. They must excrete more N than they take in. • b. They must keep the amount of N absorbed in balance with what is lost in urine and feces. • c. They actively synthesize N compounds, so must absorb more than they secrete. • d. None of the above are correct.

10. Why does a diet that is deficient in pyridoxine (vitamin B6) affect protein metabolism? • B6 deficiency sets up a cascade of events leading to premature breakdown of lipases. • The first step in amino acid catabolism requires a coenzyme derivative of B6. • B6 deficiency is critical to later steps of amino acid catabolism. • Pyridoxine is not involved in protein metabolism.

11. Why are high-density lipoproteins (HDLs) considered beneficial? a. They increase lipid metabolism. b. They decrease blood pressure. c. They increase blood pH. d. They reduce fat and cholesterol in the bloodstream.

12. Why is catabolism of dietary carbohydrates and proteins considered “not as productive” as catabolism of lipids? a. In lipids, many carbon and hydrogen atoms are already bound to oxygen. b. Digestion of dietary protein creates toxins. c. Lipids release almost twice the energy of proteins or carbohydrates. d. Carbohydrates and proteins have fewer health benefits than lipids.

13. Why are LDLs considered “bad cholesterol”? • They take cholesterol from peripheral tissues to the liver. • They deliver cholesterol to peripheral tissues. • They often end up in arterial plaques. • Both B and C are correct.

14. Why does hypervitaminosis more commonly involve fat-soluble vitamins? • Water-soluble vitamins rapidly degenerate into their component parts. • Excess fat-soluble vitamins are stored in body lipids. • Fat-soluble vitamins participate in more important reactions than do water-soluble vitamins. • All of the above are correct.

15. What characteristic of lipoproteins allows them to be made water-soluble? • They are small enough to pass through the plasma membrane. • They have a superficial coating of phospholipids and proteins. • They form compact granules. • They provide more energy than a comparable amount of glucose.

16. Which of the following vitamins can be synthesized inside the body? • a. vitamins D and K • b. vitamins B12 and C • c. vitamins A and E • d. vitamins B6 and C

17. How would a decrease in the amount of bile salts in the bile affect the amount of vitamin A in the body? • a. It would increase vitamin A. • b. It would decrease vitamin A. • c. It would have no effect, since the two are not related. • d. It depends on the absorptive state.

18. How would the BMR of a pregnant woman compare with her own BMR before she became pregnant? a. higher when pregnant b. lower when pregnant c. no difference during pregnancy d. depends on her pre-pregnancy weight

19. What effect does vasoconstriction of peripheral blood vessels have on an individual’s body temperature on a hot day? a. an increase in body temperature b. a decrease in body temperature c. no difference d. depends on the individual’s hydration level

20. In cold conditions, how does blood flow change to restrict heat loss? • Blood is diverted to the skin to decrease surface-to-volume ratio. • Heat transfer from warm blood in arteries warms cooler venous blood. • Blood flows through the superficial venous network. • Vasomotor centers are inhibited and respiration increases in depth.

21. Which of the following is a true statement? a. Gluconeogenesis is the reverse biochemical process of glycolysis. b. Glycogenesis will facilitate the storage of glucose in cells. c. Gluconeogenesis uses amino acids and lactate ions to produce glycogen. d. Both A and B are true.

22. What is NOT true with regard to glycolysis? • a. It is an anaerobic process that occurs in the cytoplasm. • b. The first step of glycolysis phosphorylates glucose and traps it in the cell. • c. The breakdown of glucose can lead to lactic acid accumulation. • d. All of the above are correct.

23. What process in the liver increases after you have eaten a high-carbohydrate meal? • a. glycolysis • b. glycogenesis • c. lipolysis • d. beta-oxidation

24. In infants, the highly vascularized tissue between the shoulder blades is referred to as ______ fat and contains adipocytes that have many ______. • a. brown; nuclei • b. brown; mitochondria • c. tan; nuclei • d. tan; mitochondria

25. In training for competitive sports, what might increase athletic performance? a. increased carbohydrates in the diet 3 days prior to an event b. increased protein in the diet 3 days prior to the event c. carbohydrate depletion/loading 3 days prior to the event d. none of the above

26. What happens during the process of transamination? • An amino group and hydrogen atom are removed. • The toxic compound ammonium (NH4) is created. • A keto acid is converted into an amino acid that can leave the mitochondria. • The liver breaks down internal proteins.