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113年 - 113 國立中山大學_學士後醫學系招生考試：普通生物及生化概論#119279

科目：學士後西醫-普通生物及生化概論 | 年份：113年 | 選擇題數：90 | 申論題數：0

試卷資訊

所屬科目：學士後西醫-普通生物及生化概論

選擇題 (90)

1. The umami receptors in the taste cells gimary detect (A) sodium.(B) fatty acid.(C) glucose.(D) glutamate.(E) glycine.
2. Signal transduction is composed of three steps including: (A) reception, lianscriptioo, and lianslation. (B) reception, translation, and response. (C) reception, transduction, and response. (D) reception, neurotransmission, and reaction.
(E) signal, translation, and response.
3. When a virus entm the lysogenic stage: (A) the viral DNA is rqplicated outside the host ceil. (B) it enters the host cell and kills the host immediately. (C) it enters the host cell, picks up host DNA, and leaves tiie cell unharmed. (D) it sits on the host cell plasma membrane with which it covers itself and the leaves the cell. (E) the viral DNA integrates into the host genome.
4. The region(s) in tiie antibody that recognize the specific antigen is/are located at: (A) light chain constant region. (B) light chain variable region. (C) heavy chain constant region. (D) heavy and light chain variable region. (E) heavy and light chain constant region.
5. Glial cells in the nervous system perform multitude of functions except (A) providing framework for neuron migration. (B) forming blood-hrain banier. (C) recycling neurotransmitter. (D) increasing the maximum depolarization potential of action potential. (E) removing waste produced by neurons.
6. In the fish gills: (A) blood and water flow in opposite directions. (B) blood and water flow in the same direction. (C) blood flowing in the gills reverses direction with every heartbeat (D) water flowing over the glls reverses direction whh every inhalation. (E) blood and water are separated by a thick polysaccharide barrier.
7. Which of the following descriptions best demonstrates the term "saltatoiy conduction"? (A) It inhibits direct neurotransmitter release. (B) It transmits the action potential at the nodes of Ranvier and tiius speeds up impulses on myelinated axons. (C) It increases neurotransmitter release at the presynaptic membrane. (D) It decreases neurotransmitter uptake at chemically gated postsynaptic channels. (E) It removes neurotransmitters from tire synaptic cleft
8. Ybu are able to resist inaction by a specific pathogen after being vaccinated against it. This is an example of: (A) innate immunity. (B) an allergy. (C) a response with defensins. (D) an autoimmune reaction. (E) immunolo^cal memory.
9. All of the following are essential nutrients in humans except: (A) vitamin B. (B) calcium. (C) glycogen. (D) linoleic acid. (E) vitamin K.
10. Which of the following is true soon after a meal? (A) Both glucagon and insulin are released. (B) The total amount of insulin in the blood decreases. (C) Glucagon is released but not insulin. (D) Neither glucagon nor insulin is released. (E) Insulin is released but not glucagon.
11. Ovulation is the response of the matured fbllicle(s) to a burst secretion of (A) estrogen. (B)luteinizing hormone. (C) progesterone. (D) prolactin. (E) oxytocin.
12. The perception of die sound pitch is mediated by (A) tiie generation of the waves in the cochlear fluid by the specific corresponding region of the oval window. (B) the vibration of the specific conesponding part on the tympanic membrane. (C) the vibration of the specific corresponding region on the basilar membrane. (D) the sequence of sound wave traveling through the auditory ossicles. (E) the music training of listeners.
13. The midpiece of a sperm cell is to (A) fuse with the jelly coat of the egg cell. (B) carry the sperm，s nucleus. (C) carry the sperm's acrosomal material. (D) generate fbe! that propels die sperm. (E) carry enzymes that are released to form a hole in the egg's jelly coat when tiie sperm encounters an egg.
14. A fish hobbyist needs to replace a certain amount of water in tiieir Ssh tanks periodically, mainly because (A) the accumulation of ammonia. (B) tiie accumulation of dirt. (C) the reduction of oxygen. (D) the increase in temperature. (E) the increase in pH.
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15. Which activity can appear in lhe ovarian cycle? (A) FSH stimulates tiie pituitary to release GnRH. (B) When FSH and LH levels foil, the corpus luteum shrinks and tiie uterine lining breaks down. (C) Luteinizing hormone stimulates the uterus to make progesterone. (D) Estrogen levels initially have a positive feedback effect on the pituitary, which is followed by higher estrogen levels causing negative feedback. (E)一律給分
16. An enzyme that breaks DNA, dispels the tension, and reseais the strand ahead of a DNA replication growing fork is called a(n) (A) topoisomerase. (B) DNA polymerase. (C) phosphodi^terase. (D) aminoacyl-tRNA synthrtase. (E) All of the above.
17. One distinction between peptide and steroid hormones is that steroid hormones: (A) bind to their receptors wMi low affinity, whereas peptide hormones bind with high affinity. (B) bind to intracellular receptors, whereas p啪de hormones bind to cell surfoce receptors. (C) are less stable than peptide hormones. (D) are generally water-soluble, whereas peptide hormones are water-insoluble. (E) act through specific receptors, whereas peptide hormones act through nonspecific receptors.
18. Iron deficiency in a cell can advereely affect electron transport at which of the following sites: (A) Cytochrome b and cytochrome c. (B) Coenzyme Q andFADH2. (C) NADHandFADH2. (D) Coenzyme Q and NADH. (E) All sites in electron transport are affected.
19. Which of the following hormones aflbcts the arcuate nucleus of the hypothalamus and ultimately results in an inhibition of nutrient intake? (A) adiponectin (B) leptin (C) ghrelin (D) glucagon (E) None of the above
20. Which one of the following amino acids is critical for glutathione to function as a redox buffer in cells? (A) glycine (B) methionine (C) glutamine (D) glutamate (E) cysteine
21. Which one is the basic unit for the ^nthesis of cholesterol? (A) Malonyl-CoA (B) Serine (C) Palmitoyl-coA (D) Isoprene (E) L-glycerol 3-phosphate
22. There is no codon for the amino acid hydroxyproline, but this amino acid is a prominent feature ol collagen structure. Which of the following is a likely explanation? (A) Hydroxyproline is substituted for proline after translation by a cut and patch mechanism. (B) Proline is covalently modified to give hydroxyproline after translation. (C) There is an alternative mechanism for synthesis of proteins that contain hydroxyproline. (D) All of the above are likely explanations. (E) It is not possible to fbnn a hypothesis from tiie information given.
23. Which metabolite levels determine whether acetyl-CoA derived from fetty acids can enter the citric acid cycle? (A) Citrate (B) Succinyl CoA (C) Oxaloacetate (D) a-Ketoglutarate (E) None of the above
24. In one turn of the citric acid cycle, how many steps in the metabolism of oxaloacetate and acetyl-CoA involve net carboxx lie acid oxidation? (A)0 (B) 1 (C) 2 (D) 3 (E) 4
25. Atherosclerosis is a condition characterized by poor metabolism of cholesterol, which is conveyed by lipoproteins. Please indicate the lipoproteins causing the development of this disease: (A) LDL (B) HDL (C) VLDL (D) Chylomicrons (E) Triglycerides
26. Gluconeogenesis is induced in die liver alter severe physical activity. Which chemical is largely used in gluconeogenesis in this case? (A) alanine (B) glucose (C) glutamate (D) lactate (E) pyruvate

27. An enzyme that follows standard Michaelis-Menten kinetics was assayed for reaction velocity at various substrate concentrations. The data are shown below:

Based on these kinetic data for the enzyme, what would be the closest estimate of the enzyme's Km value? (A) 2.0mM (B) 1.0mM (C) 250mM (D) 0.5 mM (E) 3.0mM

28. Orotate is converted to what two nucleotides which are used in nucleic acid synthesis? (A) AMP andGMP (B) TMP andCMP (C) UMPandAMP (D) GMP andCMP (E) CMP and AMP
29. How many di施rent reactions involve substrate-level phosphorylation during glycolysis? (A) 2 (B) 3 (C) 4 (D) 5 (E) 0
30. Uncoupling in mitochondria refers to: (A) Stopping electron flow but not stopping ATP synthesis. (B) Stopping ATP synthesis but not stopping electron flow. (C) Blocking the electrons ftom NADH from entering the electron transport system. (D) Interruption of electron flow. (E) None of the above.
31. Which of the following description of membrane potential is false? (A) Resting potential in neurons means when membrane potential became 0 mV. (B) Postsynaptic potentials are graded, and action potentials are all-or-none. (C) Hypetpolarization means membrane potential became more negative. (D) Under physiological condition, Na+ ions entering cells will cause depolarization. (E) Membrane potential is the result of differential ion concentration across plasma membrane of die cell.
32. Which of following is false for alternative RNA splicing? (A) removes different exon(s) to produce different mRNA (B) can allow the production of mRNA of different sizes from a single gene (C) is produced in nucleus (D) can allow the production of proteins of different sizes from a single gene (E) is processed by splicesome with just snRNA
33. Enzymes are proteins that can (A) change the specificity of reactants. (B) lower the energy barriers of reactions. (C) slow down the reactions. (D) not aHect the reactions. (E) None of the above.
34. During cell conununication, specificity is a key determinant for correct signaling. Which of the following deteimines the specificity ?(A) environment(B) ligand-receptor interaction(C) receptor activation(D) induction of effector proteins(E) None of the above
35. Which of the following demonstrates the charactoistics of a respiratory sur&ce? (A) a surfoce consisting of multiple layers of epithelial ceils (B) the exoskeleton of an insect (C) the nasal passages of a mammal (D) a thin surface consisting of a single layer of epithelial cells (E) the outer membrane of a mitochondrion
36. Which event will occur vdien food enters the stomach? (A) stomach release girelin (B) adipose tissue release leptin (C) stomach release gastrin (D) bicarbonate is released to reduce pH in the stomach (E) None of the above
37. Which muscle types are striated under the microscopic obsovation? (A) skeletal muscles only (B) cardiac muscles only (C) skeletal muscles and cardiac muscles (D) smooth muscles only (E) skeletal muscles and smootii muscles

38. Which of die following correctly dicpicts the blood velocity in humans as it flows from the aorta → arteries → arterioles → capillaries → venules → veins →venae cavae (y-axis； velocity x-axis: regions of blood vessels): (A)(B)(C)(D)(E)
39. The "hemoglobin O2 dissociation curve": (A) reflects about 50% saturation of hemoglobin in the alveoli. (B) shifts to the left when the pH decreases. (C) demonstrates that hemoglobin holds less O2when the pH is higher. (D) proves lack of dependence on CO2 levels. (E) explains how hemoglobin can bind O2 at high pH in the lungs and release it at lower pH in tissue.
40. Which of the following statement is correct in a resting skeletal muscle fiber? (A) Sarcomeres are regions between two H zones. (B) Discs ofM line proteins called the A band separate the thick filaments. (C) I bands are composed of the same thick filaments seen in the A bands. (D) Z lines are adjacent to H zones, which attach thick filaments. (E) Dark A bands contain overlapping thick and thin filaments with a central thin H zone composed only of thick filaments.
41. Which of the following reactions produces the highest amount of ATP? (A) glycolysis (B) oxidative phosphorylation (C) pyruvate oxidation (D) citric acid cycle (E) None of the above
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42. Which of the following gradient drives the ATP synthase for the production of ATP? (A) hydrogen (B) sodium (C) potassium (D) chloride (E) None of the above
43. Which of the following organelle contents has the lowest pH? (A) Golgi apparatus (B) mitochondrion (C) nucleus (D) endoplasmic reticulum (E) lysosome
44. Calcium is one of the critical ions required for the cellular functions. Which of the following is true regarding calcium? (A) Calcium can trigger cell death. (B) Calcium is critical for the activation of different proteins. (C) The free calcium concentration in the cytosol is very low. (D) The endoplasmic reticulum contains a high amount of calcium. (E) All of the above.
45. DNA subjective to genetic mutation or environmental lotion can have point mutations, but those mutations may not affect physiological functions by the proteins because: (A) the mutations do not change the amino acid encoded. (B) the mutations change lhe encoded amino acids that are not critical for the functions of proteins. (C) the mutations do affect the functions of proteins, but ofter proteins compensate for their functions. (D) None of the above. (E) All of the above.
46. How does the sensory neurons transmit stimulation strengtii to the central nervous system? (A) duration of the depolarization phase in the action potential. (B) the frequency of its action potentials. (C) the peak of the depolarization phase of an action potential. (D) how fast is neurotransmitter released from one action potential. (E) the lowest point of the hyperpolarization of an action potential.
47. Which of the following is not tfie mechanism that stops the action of neurotransmitters? (A) recycle by the pre-synaptic neuron (B) recycle by glia (C) digestion enzyme in the synaptic cleft (D) recycle by macrophages (E) All of the above are used to quickly stop neurotransmitter 's function
48. Which statement about the gut microbiota is false? (A) It can help digesting food. (B) It can increase risk of peptic ulcers. (C) It can generate specific metabolites such as short chain fetty acids. (D) It can influence neuronal development (E) It remains the same for each person through aging.
49. Which description about complement system is incorrect? (A) requires antibody to target pathogen (B) can attract phagocytic leukocyte (C) normal body cells continuously produce proteins that inactivate complement (D) activation of one complement protein can trigger the enzymatic cleavage of anotiier complement protein (E) is part of the innate immunity system
50. Lateral inhibition via amacrine cells in the mammalian retina: (A) recycles neurotransmitter molecules (B) prevents bleaching in bright light (C) is required for color vision to occur (D) enhances visual contrast (E) underlies habituation of vision
51. The enhancer is located distant from the transcriptional start site. How can an enhancer change transcription? (A) An enhancer cannot change transcription. (B) Activators bind to the enhancer and bring the bound activators closer to the promoter to trigger transcription. (C) An enhmicer can only change the transcription of another gene. (D) None of the above. (E) All of the above.
52. In vertebrate animals, spermatogenesis and oogenesis differ in that (A) oogenesis ends at menopause, whereas spermatogenesis is finished before birth. (B) oogenesis produces four haploid cells, whereas spermatogenesis produces only one sperm. (C) oogenesis begins at the onset of sexual maturity, whereas spermatogenesis begns during embryonic development. (D) cytokinesis is unequal in oogenesis, whereas it is equal in spermatogenesis. (E) spermatogenesis is not completed until after fertilization occurs, but oogenesis is completed after ovulation.
53. Calcium ion initiates skeletal muscle contraction by: (A) breaking the actin-myosin cross-bridges (B) transmitting action potentials across the neuromuscular junction (C) spreading action potentials through the T tubules (D) initiating ATP generation (E) binding to the troponin complex that subsequently displaces tropomyosin from the myosin binding sites
54. The equilibrium potential for the specific ion is corelated to the ion's polarity and (A) the voltage difference across the membrane. (B) the concentration ratio of this ion across the membrane. (C) how many ion channels are on the plasma membrane. (D) the direction of ion movement through the membrane. (E) All of the above.
55. The action potential depolarizes the cell membrane and transiently bring the membrane potential above 0 mV, then rapidly repolarizes with an undershoot, yet the membrane potential eventually returns to the resting membrane potential at ~ -70 mV. Which ion channel mediates the rapid repolarization? (A) Ca2+ channel (B)Na+channel (C) K+channel (D) ATP diannel (E) All of the above
56. Humans can smell many different kinds of odorant molecules via receptors on the olfactory neurons. These receptors belong to a class of recq)tors that can induce cAMP production to mediate the downstream responses. These odorant recqjtors are: (A) EGF receptor (B) TGF beta receptor (C) G-protein-coupled receptor (D) Tjrosine kinase receptor (E) AH of the above
57. Which of the following correctly describes a part of kidney function? (A) Collecting ducts dilute urine because they are permeable to salt but not water. (B) In tfie ascending loq)of Henle, Na+ and Cl- move into the tubules because the osmolarity of the filtrate is increased. (C) The descending loop of Henle receives filtrate from the ascending loop. (D) The distal convoluted tubule pumps water into the tubule by active transport. (E) The renal pelvis receives urine from the collecting ducts and carries it to Me ureters.
58. Which of the following exposure scheme of a foreign antigen to an animal will result in the highest titer of the induced antibody? (A) ri^ht after antigen introduction (B) a few days after antigen introduction (C) a few days after the second exposure to the same antigen (D) a few days after the exposure to anotiier antigen (E) None of the above
59. The generation of antibody diversity includes: (A) joining of V to C to J segments to make a functional light chan gene. (B) choice from several difier^it types of C segments to make a Junctional light chain gene. (C) deletion of the J segment to make a ftinctional light chain gene. (D) joining ofV to J to C segments to make a functional light chain gene. (E) initial generation of IgG followed later by IgM on a given ceil.
60. Which type of stem cel] has the widest potential to give rise to other cell types? (A) totipotent embryonic stem cells (B) pluripotent embryonic stem cells (C)unipotent stem cells (D) multipotent stem cells (E) hematopoietic stem cell
61. Nitric oxide (NO) is synthesized from: (A) lysine (B) citrulline (C) spermine (D) spermidine (E) aiginine
62. In the binding of oxygen to hemoglobin, the relationship between the concentration of oxygen and the fraction of binding sites occupied can be best described as: (A) hyperbolic (B) linear with a negative slope (C) linear with a positive slope (D) random (E) sigmoidal

63. Which one is the essential ingredient for biosynthesis of fatty acid?  (A) (B)(C) (D) (E)
64. The urea cycle and citric acid cycle are linked by (A) citrulline and fumarate. (B) citrulline and ornithine. (C) citrulline and argininosuccinate. (D) ornithine and arginine. (E) fumarate and aspartate.
65. Which one is not a derivative of cholesterol? (A) cortisol (B) testosterone (C) arachidonic acid (D) bile acid (E) vitamin D3
66.5-Fluorouracil (5-FU) is used to treat cancers. It is a mechanism-based inhibitor of______. (A) ribonucleotide reductase (B) Ihymidylate synthase (C) adenylosuccinate lyase (D) GMP synthetase (E) xanthine oxidase
67. In amino acid metabolism, threonine is converted into acetyi-CoA and pyruvate while proline is converted into a-ketoglutarate. Classify each of these amino acids. (A) Threonine and proline are ketogenic. (B) Threonine is ketogenic and glucogenic； proline is ketogenic. (C) Threonine is ketogenic； proline is glucogenic. (D) Threonine is ketogenic and glucogenic； proline is glucogenic. (E) None of the above.

68. Ketone bodies are produced by file β-oxidation of an excess of acetyl-CoA. Which of the followings are ketone bodies? (A) ①②③ (B) ①③④ (C) ②④ (D) ③④ (E) ②④⑤
69. Many biomolecules are derived from amino acid precursors. Serotonin and dopamine are synthesized from ____and____ , respectively. (A) histidine； tyrosine (B) phenylalanine； tryptophan (C) tryptophan； tyrosine (D) histidine； tryptophan (E) tryptophan； histidine
70. Several nucleotide bases undergo spontaneous loss of their exocyclic amino groups (deamination). Deamination of the nucleotide bases cytosine and 5-methylcytosine yields nucleotide bases: (A) hypoxanthine and xantitine, respectively. (B) uracil and thymine, respectively. (C) uracil only. (D) uracil and hypoxanthine, respectively. (E) thymine and uracil, respectively.
71. If a cell were unable to synthesize or obtain tetrahydrofblic acid (H4 folate), it would probably be deficient in the biosynthesis of: (A) isoleucine (B) leucine (C) lysine (D) methionine (E) serine
72. Which of the following statements explains why allopurinol is able to prevent gout? (A) It binds to uric acid thus preventing the fonnation of uric acid crystals. (B) It acts as a diuretic to increase the elimination of uric acid. (C) It inhibits tiie production of uric acid and allows for the more highly soluble xanthine and hypoxanthine to be excreted from the body. (D) It stimulates the purine salvage pathway, thus eliminating the need for production of uric acid. (E) None of the above.
73. In anaerobic circumstances, the re-oxidation ofNADH generated during glycolysis occurs through the following reaction: (A) fructose 1,6-bisphosphate → glyceraldehyde-3P + dihydroxyacetone-P (B) glyceraldehyde-3P → 1,3-DPG (C) pyruvate → lactate (D) dihydroxyacetone-P → glyceraldehyde-3P (E) malate → oxaloacetate
74. Asians and Native Americans may experience flushing and discomfort after consuming a small amount of ethanol in alcoholic beverages. This reaction is attributed to genetic variation in an enzyme responsible for metabolizing the liver metabolite of alcohol. What is this motabolite? (A) methanol (B)acetone (C) glycerol (D) acetaldehyde (E) pyruvate
75. Match the correct form of tetrahydrofolate with the corresponding reaction for Wiich it acts as a coenzyme. (A) 5,10-methenyl-THF: biosynthesis of purines (B) 5-methyl-THF: dUMP→ dTMP (C) 5,10-methylene-THF: glycine →serine (D) 5,10-mcthenyl-THF: methionine→homocysteine (E) All of the above
76. The percentage saturation of hemoglobin by oxygen is increased when one of the following is increased: (A) concentration of 2,3 bisphosphogiycerate (B) concentration of hydrogen ions (C) concentration of Hb (D) parUal pressure of CO2 (E) partial pressure of O2
77. Which of the following describes the coenzyme involved with thymidylate synthase? (A) 5-mefliyl-THF serves as the methyl donor. (B) 10-methyl-THF serves as the methyl donor. (C) 5,10-methylene-THF serves as both methylene donor and reducing agent. (D) 5,10-methenyl-THF serves as both methylene donor and reducing agent (E) S-adenosylmethionine serves as the methyl donor.
78. Which statement regarding allosteric regulation of enzyme activity is false? (A) Allosteric regulators can either activate or inhibit enzyme function. (B) Binding of allosteric effectors induces a confbimational change in the enzyme. (C) Homotropic allosteric effectors compete with substrate for binding sites. (D) Allosteric enzymes usually consist of multiple subunits. (E) Sigmoidal kinetic plots are indicative of tiw presence of allosteric binding sites.

79. Consider the enzyme kinetic model:

Which expression best describes die INITIAL rate of ES formation under the standard Michaelis- Menten quasi steady-state assumption? (A) k1[E][S] (B) k1[E][S]-k-1[ES] (C) k1[E][S]-(k-1+k2)[ES] (D) k2[ES] (E)k-1[ES]+k2[ES]
80. In bacteria, the biosynthetic routes for proline and arginine diverge when glutamate is N-acetylated for arginine synthesis. Which of the following explains why acetylation is required for arginine synthesis but not proline synthesis? (A) Acetylation alters the pKa of the amine group. (B) Acetylation prevents reduction of the amine group in N-acetylglutamate-δ-semialdehyde. (C) Acetylation activates tiie amine group for synthesis of the guanidine group of arginine. (D) Acetylation prevents the cyclization of N-acetylglutamate-δ-semialdehyde. (E) None of the above.
81. In skeletal muscle, PFK-2 is not subject to regulation by phosphorylation. However, in the liver, what is the effect of dephosphorylation of PFK-2? (A) Degradation of fructose-1,6-bisphosphate (B) lucreased transcription of PFK-2 (C) Increased turnover of PFK-2 (D) Reduced production of fh)ctose-2,6-bisphosphate (E) Enhanced production of fiructose-2,6-bisphosphate
82. A researcher wants to isotope label purines with 15N for future spectroscopic studies. Which substrates when labeled with the heavy nitrogen would result in the most1 15N-enriched purines through de novo synthesis? (A) Glutamine, aspartate, glycine (B) Glycine, glutamine, N10-fbrmyl-THF (C) Aspartate, glutamine, asparagine (D) Glycine, carbamoyl aspartate, glutamine (E) Aspartate, glycine, 5-phosphoribosyl»a-pyrophosphate
83. Different carbon positions of 14C-labeled glucose are tested within the crude tissue extract containing enzymes from the pentose phosphate pathway. Which specific carbon position will lead to the fastest generation of 14CO2： (A) C-6 (B) C-5 (C) C-4 (D) C-3 (E) C-1
84. Which of the following is true regarding the control of pyruvate dehydrogenase? (A) It is inhibited by succinyl-CoA. (B) It is activated by acetyl-CoA. (C) It is inhibited by ATP. (D) It is inhibited by NAD+. (E) None of the above.
85. Which of the following is an end product of glucooe metabolism via either aerobic or anaerobic means? (1) fructose (2) carbon dioxide (3) lactate (A)(1)and(2)(B)(2) and (3) (C) (1)only (D)(2)only (E) (3) only
86. Which is tiie order of compounds produced in the conversion of glucose to pyruvate?
(PEP = phosphoenolpyruvate) 
(1) fructose-6-phosphate
(2) 1,3-phosfdioglyceric acid
(3) fhictose-bisphosphate
(4) PEP
(5) 3-phosphoglyceric acid (A) (1),(2), (3), (4), (5) (B) (1), (3), (2), (5), (4) (C) (2), (3), (1),(4), (5) (D) (2), (3), (1),(5), (4) (E) (3), (1),(2), (5), (4)
87. What will occur when insulin is released? (A) Insulin binds to receptors on cell sur&ces. (B) A protein kinase cascading leads to glycogen synthesis. (C) Insulin stimulates the GLUT4 transport protein system in muscle cells. (D) Glucose transporters move glucose out of tiie blood and into the cell. (E) All of tiie above.
88. Which of tiie fbllowing is a regulatory enzyme in gluconeogenesis?
(1) pyruvate kinase.
(2) pyruvate carboxylase.
(3) phosphoenolpyruvate carboxykinase.
(4) glucose-6-phosphatase. (A)(1)，(2) and (3) (B) (1), (2) and (4) (C) (2),(3) and (4) (D) (2) and (3) (E) (1), (2), (3) and (4)
89. Which of the following statement is true about [ipoic acid? (A) It contains one disulfide group in its reduced form and two sulfhydryl groups in its oxidized form. (B) It contains one disulfide group in its oxidized form and two sulfhydryl groups in its reduced form. (C) It contains two disulfide groups in its reduced form and one sulfhydiyl group in its oxidized form. (D) It contains two disulfide groups in its oxidized fonn and one sulfliydiyl group in its reduced form. (E) None of the above.
90. Which of the following statement regarding electron transport and ATP synthesis is not true?
(1) The synthesis of ATP is directly linked to the oxidation ofNADH.
(2) The synthesis of ATP in mitochondria is driven by a proton or pH gradient.
(3)The reoxidation ofNADH and FADH2 indirectly creates a proton gradient that is involved in ATP synthesis. (A) (1)only (B) (2) only (C) (3)only (D) All are correct (E) None is correct.

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