21. The following figure shows how Cyclic AMP-dependent protein kinase (PKA) is regulated. The catalytic subunits are controlled by:

(A) allosteric control
(B) zymogen control
(C) covalent modification
(D) intrasteric control
(E) product inhibition.

17. We have two enzymes maltose phosphorylase and sucrose phosphorylase catalyzing the following reactions: With the presence of unlabeled G-1-P and sucrose phosphorylase in an isotope-labeled 32P； solution, we found the "P" on G-1-P can also be isotope-labeled after some time. However, maltose phosphorylase cannot do the same. Which of following is true: (A) Sucrose phosphorylase catalyzes a reaction following double-displacement mechanism (B) Sucrose phosphorylase catalyzes a reaction requiring the formation of tertiary complexes (C) Maltose phosphorylase catalyzes a reaction following what is called "Ping-Pong mechanism" (D) Maltose phosphorylase catalyzes a reaction where enzyme is covalently modified during the catalysis though the modification occurs only transiently (E) NAD+-dependent dehydrogenases use a random single-displacement catalytic mechanism

18. About Near Attack Conformation (NAC), which of the following is NOT true? (A) Computer simulations find that the chance of NAC to form in the enzyme active site can be 300,000 times larger than that of NAC in the absence of the enzyme (B) the energy difference of E.NAC→E.X+ is smaller than that of NAC→X+ where X+ means the transition state (C) The enzymatic catalysis benefits from lowering the energy barrier of S→NAC (D) The transition state analog has a configuration closer to the transition state than the NAC (E) Both the catalyzed and uncatalyzed reactions require the formation of NAC

19. Which of the following will NOT change the Phosphorylases' activity? The energy level in our bodies. (A) Glucose-6-P (B) Caffeine (C) AMP (D) ADP (E) ATP

20. About hemoglobin, which of the following is NOT true? (A) It forms different intra/intermolecular hydrogen-bonding patterns in the 'T' and 'R' forms (B) It demonstrates a mixed KNF and MWC model (C) It binds oxygen weaker than myoglobin below the P50. (D) It is regulated by pH values (E) It transfers CO₂ to the lung via the oxygen binding pocket.

22. Insulin in the bloodstream is a response to increased blood glucose, and: (A) stimulates gluconeogenesis, (B) inhibits glycolysis, (C) stimulates glycogen synthesis in muscle and liver, (D) stimulates glycogen breakdown in liver, (E) inhibits phosphoprotein phosphatase-1.

複選題23. Which of the following can be used as a substrate for gluconeogenesis in the liver? (A) alanine, (B) glutamic acid, (C) glycerol, (D) succinate, (E) all of the above.

24. The primary storage form of lipid is ______ and it is normally stored in the ______. (A) phospholipid； liver, (B) cholesterol； muscles, (C) monoacylglycerol； adipocytes, (D) triacylglycerols； adipocytes, (E) triacylglycerols； liver.

25. Bile salts are important in the initial digestion of triacylglycerols in the intestine because they: (A) are coenzymes for pancreatic lipase, (B) convert the inactive lipase into the active form, (C) emulsify the triacylglycerol globules to produce greater surface area which will increase the activity of the lipase, (D) activate the cleavage at the C-2 position, (E) permit greater permeability of the triacylglycerols through the intestinal membrane.

26. For the complete oxidation of a saturated fatty acid with 18 carbons, how many times must the β-oxidation cycle be repeated? (A) 4, (B) 7, (C) 8, (D) 6, (E) 16.

27. Hormones such as glucagon ______ glycolysis by activating CAMP-dependent protein kinase that will ______ pyruvate kinase to ______ the enzyme. (A) activate； carboxylate； activate, (B) activate； phosphorylate； activate, (C) activate； phosphorylate； inhibit, (D) inhibit； phosphorylate； inhibit, (E) inhibit； phosphorylate； activate.