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107年 - 107 高雄醫學大學_學士後醫學系招生考試：普通生物學及生化概論#118860

科目：學士後西醫-普通生物及生化概論 | 年份：107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._________ are membrane protrusions that facilitate the absorption of nutrients. What is the name of these protrusions and what cytoskeletal element forms their internal skeleton? (A) Microvilli, microtubules (B) Microvilli, actin filaments (C) Microvilli, intermediate filaments (D) Villi, microtubules (E) Villi, actin filaments
2. What causes a differentiating B cell to become committed to producing only one species of antibody molecule? (A) DNA rearrangements in the genome (B) RNA rearrangements in the genome (C) protein rearrangements in the genome (D) DNA rearrangements in the mitochondria (E) RNA rearrangements in the mitochondria
3. Which of the following about neuron is incorrect? (A) It is a polarized cell. (B) Peripheral nervous system includes autonomic and somatic nervous systems. (C) The generation of action potential is related to the electrochemical gradient across the plasma membrane. (D) Myelin sheath is a protein-rich substance that surrounds the axon of some neurons, forming an electrically insulating layer. (E) Neurofilaments are intermediate filaments found in neurons.
4. In the life cycle of an angiosperm, which of the following cells or tissues are diploids? (A) generative cells (B) microsporocyte (C) antipodal cells (D) tube cells (E) polar nuclei of the embryo sac
5. The black dots that cover strawberries are actually individual fruits from a flower with multiple carpels. The fleshy and tasty portion of a strawberry derives from the receptacle of the flower. Therefore, a strawberry is ________. (A) both an aggregate fruit and an accessory fruit (B) both a multiple fruit and an accessory fruit (C) both a multiple fruit and an aggregate fruit (D) both a simple fruit and an aggregate fruit (E) both a simple fruit and an accessory fruit
6. During splicing, which major molecular component of the spliceosome catalyzes the excision reaction? (A) protein (B) DNA (C) RNA (D) lipid (E) sugar
7. Which of the following statements regarding the body plans of animal is correct? (A) Cnidarian are bilateral symmetry. (B) Nematodes are acoelomate. (C) Platyhelminthes are radial symmetry. (D) Annelids are psudocoelomate. (E) Chordates are deuterostomia.
8. In a phylogenetic tree, a group is composed of some species but not their most recent common ancestor. This is an example of ________. (A) monophyletic group (B) paraphyletic group (C) polyphyletic group (D) polytomy (E) dicotomy
9. Bioluminescence is an important strategy for attracting preys in which of the following marine zone? (A) benthic zone (B) intertidal zone (C) oceanic zone (D) aphotic zone (E) photic zone
10. Which of the following descriptions regarding sensory receptors is correct? (A) Sense of smell is generated through mechanoreceptors. (B) Vision is generated through chemoreceptors. (C) Thermoreceptors detect change of pressures. (D) Nocireceptors detect pain feelings. (E) Photoreceptors detect sense of taste.
11. Which statement is incorrect concerning protein translation? (A) Ribosomes in prokaryotic and eukaryotic cells have two subunits of unequal size. (B) Sequences exist in prokaryotic and eukaryotic rRNA that are so similar, that they likely derive from a common ancestor. (C) Initiator tRNA recognizes AUG codons during initiation at the P site of ribosome. (D) The 30S and 50S ribosomal subunits of E. coli combine to generate an 80S subunit. (E) Polysomes are rich in cells active in protein synthesis.
12. Testosterone is synthesized primarily by the ________. (A) Leydig cells (B) hypothalamus (C) sperm cells (D) anterior pituitary gland (E) seminiferous tubules
13. Which of the following orders regarding mammalian embryogenesis is correct?
1. cleavage
2. gastrula
3. blastula
4. cortical reaction
5. neurulation
6. acrosomal reaction (A) 132645 (B) 231546 (C) 461523 (D) 641325 (E) 654132
14. Which of the following descriptions regarding the embryonic germ layers is correct? (A) Pituitary gland is derived from mesoderm. (B) Thymus is derived from mesoderm. (C) Teeth are derived from mesoderm. (D) Adrenal cortex is derived from mesoderm. (E) Adrenal medulla is derived from mesoderm.
15. Which of the following about chloroplasts and mitochondria is incorrect? (A) They are of the appropriate size to be the descendants of bacteria. (B) They contain circular DNA not associated with histones. (C) They contain their own genome and produce all proteins they need. (D) Their ribosomes are more similar to those of bacteria than to those of eukaryotes. (E) Their membranes have enzymes and transport systems that resemble those in the plasma membrane of prokaryotes.
16. ________ are commonly referred to, respectively, as the 21st and 22nd amino acids. (A) Selenocysteine and pyrrolysine (B) Adenine and guanine (C) Thymine and uracil (D) Hydroxyproline and hydroxylysine (E) β-Alanine and D-alanine
17. Which of the following sequences is not found in an E. coli vector (such as pET21)? (A) replication origin (ori) (B) multiple cloning sites (MCS) (C) antibiotic resistance gene (AmpR ) (D) Shine-Dalgarno sequence (E) CMV promoter
18. Which of the following metabolic pathways is strictly anabolic? (A) glycolysis (B) gluconeogenesis (C) citric acid cycle (D) pentose phosphate cycle (E) β-oxidation of fatty acids
19. Dihydrouracil and pseudouridine are found predominantly in ________. (A) mRNA (B) rRNA (C) tRNA (D) Z form DNA (E) siRNA
20. Which oil listed below contains more than 60% unsaturated fatty acids? (A) beef (B) milk (C) coconut (D) palm (E) olive
21. In order to perform PCR, the following reagents must be included ________. (A) DNA fragment, primers flanking the region of interest, dNTPs, ddNTPS, DNA Polymerase (B) DNA fragment, primers flanking the region of interest, dNTPs, DNA Polymerase (C) DNA fragment, one primer, dNTPs, DNA Polymerase, DNA ligase (D) DNA fragment, primers flanking the region of interest, dNTPs, DNA Ligase (E) none of the above
22. The coding sequence of DNA is 5’-CGCTATAGCGTTT-3’. Which of the following sequences is its RNA transcript (mRNA)? (A) 3’-CGCTATAGCGTTT-5’ (B) 5’-CGCUAUAGCGUUU-3’ (C) 3’-GCGATATCGCAAA-5’ (D) 5’-UUUCGCUAUAGCG-3’ (E) 5’-CGCTATAGCGTTT-3’
23. Gout is caused by ___ over degradation results in accumulation of uric acid. (A) purine (B) pyrimidine (C) fatty acid (D) glucose (E) amino acid
24. Which of the following peptides has the largest molar extinction coefficient for UV absorption at 280 nm? (A) Tyr-Glu-Gly-Lys (B) Phe-Arg-His-Phe (C) Gln-His-Cys-Ala (D) Val-Asp-Met-Trp (E) Ile-Lys-Asn-Ser
25. What main compound is transported from the cytosol to the mitochondria via malate-aspartate shuttle? (A) NADH (B) NH4 + (C) FADH2 (D) O2 (E) oxaloacetate
26. What enzyme can generate citrulline? (A) NO synthase (B) citrate dehydrogenase (C) citrate oxidase (D) citrulline synthetase (E) citrate peroxidase
27. The Tang Prize in Biopharmaceutical Science was awarded to Dr. Feng Zhang for ________. (A) cancer immunotherapy (B) vesicular transport (C) mitochondrial fusion and fission (D) discovery of nerve growth factor (E) the development of CRISPR/Cas9 as a genome editing platform
28. What amino acid residue is required for the protein region to interact with Src homology 3 (SH3) domain? (A) serine (B) proline (C) lysine (D) arginine (E) leucine
29. Molecular chaperones assist proteins in the formation of ________. (A) aggregates (B) 3° structure (C) amide bonds (D) 1° structure (E) none of the above
30. Supercoiled DNA can be relaxed by ________. (A) catenation (B) intercalation (C) nicking one strand (D) hybridization (E) denaturation 
31. Which of the following statements about transporters is incorrect? (A) Proton pump is an electro-genic pump. (B) Transport of sodium ions and potassium ions through sodium-potassium pump is an active transport. (C) The membrane potential acts as an energy source that affects the traffic of charged substances across the membrane. (D) Facilitated diffusion is a diffusion of solutes against their gradients. (E) The transport of glucose via glucose transporter is affected by the temperature.
32. The following compounds function as neurotransmitters except ________. (A) acetylcholine (B) creatine (C) γ-aminobutyrate (D) 3,4-dihydroxyphenylalanine (DOPA) (E) glutamic acid
33. Which of the following about endocrine system is incorrect? (A) Testis is a part of endocrine system. (B) T3 and T4 are hormones derived from tyrosine. (C) The alpha cells of pancreas produce glucagon to increase the blood glucose level. (D) The heart is an endocrine organ because the cardiac cells produce atrial natriuretic peptide in response to high blood pressure. (E) Estrogen is a water-soluble hormone that regulates the female reproductive system and sex characteristics.
34. When electrons flow along the electron transport chain of mitochondria, which of the following changes occurs? (A) NAD+ is oxidized. (B) The pH of the matrix is increased. (C) ATP synthase pumps protons by active transport. (D) The cytochrome c of the electron transport chain phosphorylates ADP to ATP. (E) The electron donor of complex I in the chain is FADH2.
35. Which of the following is a true distinction between cellular respiration and lactate fermentation? (A) NADH is oxidized by the electron transport chain only in respiration. (B) Substrate-level phosphorylation is unique to lactate fermentation. (C) Only respiration oxidized glucose. (D) Respiration, but not lactate fermentation, is a catabolic pathway. (E) NAD+ functions as an oxidizing agent only in respiration.
36. Which of the following about cardiac muscle is correct? (A) They contract only when stimulated by neurons. (B) They lack an orderly arranged actin and myosin. (C) They lack the striations of skeletal muscle. (D) They have less sacroplasmic reticulum and thus contract more slowly than smooth muscle. (E) They are connected by intercalated discs, through which action potentials spread to all cells in the heart.
37. Which of the following short-distance transport routes in plants goes through plasmodesmata? (A) symplastic route (B) transmembrane route (C) apoplastic route (D) apoptosis route (E) aquaporin route
38. In the process of photosynthesis, which of the following is not involved in the creation of H+ gradient thylakoid lumen and stroma that generates ATP? (A) reduction of NADP+ (B) splitting of water in the thylakoid lumen (C) PQ cycle of the electron transport chain and its reaction to cytochrome b6f complex (D) regeneration of RuBP (E) electron transport
39. X chromosome inactivation is an epigenetic mechanism that silences the majority of genes on one X chromosome. The inactivation appears to involve regions of _________. (A) mutated genes (B) intense transcription (C) hyper-methylated DNA (D) hypo-methylated DNA (E) inverted genes
40. According to the intermediate disturbance hypothesis, species richness is higher in areas of intermediate levels of disturbance. Why would species richness be lower at low levels of disturbance? (A) A high nutrient level poisons lots of species. (B) Competitive exclusion results in the extinction of species. (C) Ecological niches are less partitioned in places with high levels of disturbance. (D) Lack of disturbance slows down the evolution of new species. (E) Low level of disturbance results in low soil fertility.
41. Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Specifically, Taxol must affect _________ . (A) the formation of the mitotic spindle (B) anaphase (C) formation of the centrioles (D) chromatid assembly (E) the S phase of the cell cycle
42. Which of the following about transposable elements is correct? (A) occurs only in bacteria (B) occurs only in plants (C) moves genes between homologous regions of DNA (D) scatters genes to a new loci in the genome (E) plays little role in evolution
43. The difference between pinocytosis and receptor-mediated endocytosis is that _________ . (A) pinocytosis brings only water molecules into the cell, but receptor-mediated endocytosis brings in other molecules as well (B) pinocytosis increases the surface area of the plasma membrane whereas receptor-mediated endocytosis decreases the plasma membrane surface area (C) pinocytosis requires cellular energy, but receptor-mediated endocytosis does not (D) pinocytosis is nonselective in the molecules it brings into the cell, whereas receptor-mediated endocytosis offers more selectivity (E) pinocytosis can concentrate substances from the extracellular fluid, but receptor-mediated endocytosis cannot
44. How does extracellular glucose inhibit transcription of the lac operon? (A) by strengthening the binding of the repressor to the operator (B) by weakening the binding of the repressor to the operator (C) by degrading the lac operon gene (D) by inhibiting RNA polymerase from opening the strands of DNA to initiate transcription (E) by reducing the levels of intracellular cAMP
45. Which of the following traits do archaeans and bacteria share?
 1. composition of the cell wall
2. presence of plasma membrane
3. lack of a nuclear envelope
4. identical rRNA sequences (A) 1 and 2 (B) 1 and 3 (C) 1 and 4 (D) 2 and 3 (E) 2 and 4
46. Asbestos is a material that was once used extensively in construction. One risk from working in a building that contains asbestos is the development of asbestosis caused by the inhalation of asbestos fibers. Cells will take up asbestos by phagocytosis, but are not able to degrade it. As a result, asbestos fibers accumulate in ________. (A) rough ER (B) lysosomes (C) Golgi apparatus (D) nuclear (E) peroxisomes
47. Which of the following is more likely an application of the concept of molecular clock? (A) estimate the origin time of HIV virus (B) estimate the vertical migration pattern of benthic diatoms (C) estimate the rhythmic behaviors of intertidal species in the lab (D) estimate the genetic diversity of a population (E) estimate the reason for dinosaur extinction
48. Stem cell transplants may someday be used to treat Parkinson's disease. Researchers are hopeful that these cells would alleviate the symptoms of Parkinson's disease by ________. (A) preventing temporal lobe seizures (B) repairing sites of traumatic brain injury (C) replenishing missing ion channels (D) secreting the neurotransmitter dopamine (E) changing in myelination of axons
49. Prezygotic isolating mechanisms act to limit hybridization and maintain the genetic identity of closely-related species. For sympatric corals that do synchronized spawning, what is the most likely isolation mechanism? (A) behavioral isolation (B) temporal isolation (C) habitat isolation (D) gametic isolation (E) hybrid breakdown
50. How does a noncompetitive inhibitor decrease the rate of an enzyme reaction? (A) by binding to the active site of the enzyme, thus preventing binding of the normal substrate (B) by binding to an allosteric site, thus changing the shape of the active site of the enzyme (C) by decreasing the free-energy change of the reaction catalyzed by the enzyme (D) by acting as a coenzyme for the reaction (E) by binding to the substrate, thus changing its shape so that it no longer binds to the active site of the enzyme
51. Which of the following statements regarding insects is correct? (A) Incomplete metamorphosis have a pupal stage. (B) Metamorphosis from the larval stages to the adult occurs during pupal stage. (C) Insects are analids. (D) Book lung is a special organ in insects. (E) Insects are lophotrochozoa.
52. Which of the following correctly describes the relationships between gross primary production (GPP), net primary production (NPP), autotrophic respiration (Ra), net ecosystem production (NEP) and total respiration of all organisms in the ecosystem (Rt)? (A) NPP = GPP - Rt (B) GPP = NPP - NEP (C) Rt + Ra + NPP = GPP (D) NPP = GPP - Ra (E) GPP = NEP + Rh
53. Which of the following statements regarding vertebrates is correct? (A) Chondrichthyans have operculum. (B) Amphibians are amniotes. (C) Marsupials have fully developed placenta. (D) Osteichthyans have swim bladders. (E) None of the above.
54. Which of the following descriptions regarding appetite control of animal is correct? (A) Ghrelin is produced by small intestine. (B) Leptin triggers the feelings of hunger. (C) Insulin suppresses appetite by acting on intestine directly. (D) PYY acts as appetite suppressant. (E) None of the above.
55. Which of the following statements regarding John Gurdon's experiments for nucleus transfer is correct? (A) Frog eggs were enucleated by laser treatment. (B) Donor nucleus from frog intestine cells cannot be developed into a tadpole. (C) Donor nucleus from less differentiated cells are less likely to be developed into a tadpole. (D) He concluded that the more differentiated cells may generate changes in the nucleus. (E) None of the above.
56. In bird, the sex chromosome presented in egg, rather than sperm, determines the gender of the offspring. Therefore, females are ZW while males are ZZ. Which of the following statements is correct? (A) W linked recessive mutation will never cause disease in males. (B) Z linked recessive mutation will only affect female offspring. (C) Unfertilized egg cells only carry Z chromosome. (D) Some sperm cells carry W chromosome. (E) None of the above.
57. Which of the following descriptions regarding circulatory system is correct? (A) The circulatory fluid in closed circulatory system is called hemolymph. (B) Blood in right ventricle will first deliver to aorta. (C) Sinoatrial node is located in left atrium. (D) Erythropoietin is produced from kidney. (E) Mammals employ positive pressure breathing.
58. Which of the following descriptions regarding neuronal disorders is correct? (A) Amyloid plaques are always observed in schizophrenia. (B) Additive substances such as alcohol affect the dopamine regulation in brain. (C) Dopamine can be used to treat Alzheimer patients. (D) Parkinson's patients lost their ability to recognize people. (E) Depression is a rare nervous system disorder.
59. Which of the following descriptions regarding muscle is correct? (A) The length of thick filament will change in fully muscle contraction. (B) A motor unit consists of multiple motor neurons and muscle fibers. (C) Myoglobin binds oxygen tighter than hemoglobin does. (D) Ca2+ binds with tropomyosin to initiate muscle contraction. (E) Insect's skeletal muscles are grossly different from those of vertebrates.
60. Radiolabelled isotope dating is an important method to determine the age of a fossil. A14C content analysis of an animal fossil showed that its content is 0.01562 fold as much 14C as the atmosphere. The half-life of 14C is 5730 years. The age of the fossil is close to which of the following? (A) 1000 years (B) 5730 years (C) 35000 years (D) 70000 years (E) 100000 years
61. Which of the following descriptions about the Michaelis-Menten equation is false? (A) KM measures the substrate concentration at which the reaction rate is 1/2Vmax. (B) An enzyme with a low KM means that it has low affinity for its substrate. (C) An enzyme with a low kcat means that it has a low catalytic rate. (D) The turnover number, kcat, measures the rate of the catalytic process. (E) The ratio kcat/KM is a convenient measure of enzyme efficiency.
62. Which description about Hb (hemoglobin) is false? (A) HbF has an α2γ2 structure. (B) HbA has an α2β2 structure. (C) HbF has a much higher affinity for 2,3-BPG than HbA does. (D) 2,3-BPG lowers the O2 affinity of HbA. (E) 2,3-BPG is found inside red blood cells.
63. The carbon skeleton produced by transamination of aspartate enters the citric acid cycle as ______. (A) acetyl-CoA (B) pyruvate (C) fumurate (D) oxaloacetate (E) α-ketoglutarate
64. 5-phosphoribosyl-1-pyrophosphate (PRPP) is a precursor in the synthesis of all of the following products except ________. (A) histidine (B) tryptophan (C) arginine (D) UMP (E) AMP
65. In eukaryotic cells, mRNA modification includes __________. (A) splicing out exons and join introns (B) add a cap at 3’ end to protect the 3’ end (C) add a phosphate group at 5’ end to increase stability (D) remove nucleotides at 3’ end before addition of a poly A tail (E) remove 3’UU and attach CCA
66. What is the appropriate order for oxidation of glucose to CO2, H2O and ATP?
 1.convert pyruvate to acetyl CoA 
 2.electron-transport chain
3.citric acid cycle
4.oxidative-phosphorylation
5.glycolysis (A) 3→5→1→4→2 (B) 5→1→3→2→4 (C) 1→4→5→2→3 (D) 3→1→4→2→5 (E) 4→1→3→5→2
67. Cooperative binding of a ligand to a protein is a form of allosteric binding. Which of the following statements is false? (A) It is usually associated with proteins with multiple subunits. (B) The binding of one ligand affects the affinities of other unfilled binding sites. (C) The Hill plot results in a hyperbolic curve. (D) It results in a sigmoidal binding curve. (E) Hill coefficient (nH) is a measure of the degree of cooperativity.
68. Ubiquitin is a small protein which is covalently linked to proteins designated for destruction via ____. (A) ATP-dependent proteases in lysosomes (B) ATP-dependent proteases in proteasomes (C) ATP-dependent proteases in ribosomes (D) ATP-independent proteases in endosomes (E) ATP-independent proteases in peroxisomes
69. What of type reaction promotes the conversion of phosphatidylserine to phosphatidylethanolamine? (A) transamination (B) acetylation (C) dehydrogenation (D) methylation (E) decarboxylation
70. What compound does not exist in the glyoxylate cycle? (A) citrate (B) α-ketoglutarate (C) isocitrate (D) malate (E) oxaloacetate
71. Which compound is not one-carbon carrier in metabolism? (A) tetrahydrobiopterin (B) formyl-tetrahydrofolate (C) methyl-tetrahydrofolate (D) biotin (E) S-adenosylmethionine
72. Which of the following statements regarding yeast two-hybrid analysis is false? (A) The goal is to bring together the DNA-binding domain and the activation domain of the yeast Gal4 protein. (B) Gal4 protein has two domains: one that binds a specific DNA sequence domain, the other activates RNA polymerase to synthesize tRNA from an adjacent gene (reporter gene). (C) A library can be set up to fuse to the Gal4 protein DNA-binding domain. (D) The interacting protein can be quickly identified by DNA sequencing of the fusion protein′s gene. (E) Some false positive results occur, due to the formation of multiprotein complexes.
73. What amino acid residues in some membrane-associated proteins are covalently linked to myristoyl or farnesyl groups? (A) asparagine and lysine (B) cysteine and glycine (C) serine and tyrosine (D) asparagine and serine (E) proline and lysine
74. What main component in plasma membrane has the oligosaccharide head groups to determine human blood types (O, A, B, and AB)? (A) caveolin in lipid raft (B) clathrin in apical surface (C) sphingolipid (D) phospholipid (E) cholesterol
75. What enzyme is frequently used for the measurement of the concentrations of glucose in blood? (A) glucokinase (B) glucose epimerase (C) glucose dehydrogenase (D) glucose dehydration (E) glucose oxidase
76. What two classes of enzymes play an important role in generating and propagating a recombinant DNA molecule in DNA cloning? (A) recombinases and DNA polymerase α (B) recombinases and DNA polymerase γ (C) restriction endonucleases and DNA ligases (D) restriction endonucleases and recombinases (E) restriction endonucleases and reverse transcriptase
77. Insulin exerts its action through plasma membrane receptors to regulate the level of blood glucose. An elevated insulin level in the blood _______. (A) results from a below-normal blood glucose level (B) inhibits glycogen synthesis in liver and muscle (C) stimulates synthesis of fatty acids in liver and triacylglycerols in adipose tissue (D) inhibits glucose uptake by liver (E) stimulates glycogen breakdown in liver
78. Which of the following statements regarding polysaccharide is correct? (A) The glucose residues are linked by (β1→4) glycosidic bonds in cellulose. (B) In bacteria, dextrans are made up of (α1→4)-linked poly-D-glucose. (C) Chitin is a linear heteropolysaccharide composed of N-acetylglucosamine. (D) Glycogen is a polymer of glucoses with (α1→4)-linked branches. (E) Amylose is a branched glucose polymer.
79. Which of the following amino acids belong to ketogenic and glucogenic?
(a) Trp (b) Phe (c) Tyr (d) Arg (e) Met (A) (a) (c) (e) (B) (a) (b) (c) (C) (b) (c) (e) (D) (b) (d) (e) (E) (a) (d) (e)
80. Which of the following statements regarding biosynthesis of fatty acids is correct? (A) NADH is required in the biosynthesis of fatty acids. (B) Fatty acids synthase I in vertebrates consists of 4 polypeptide chains. (C) Fatty acids synthase I is not a homodimer molecule. (D) HCO3 - is involved in biosynthesis of fatty acids. (E) There are 8 active sites in fatty acids synthase I.

81. Which of the following statements about Klenow fragment is false? (A) Klenow fragment is derived from E. coli DNA polymerase I. (B) It contains DNA polymerase activity. (C) It contains 3’→5’ exonuclease activity. (D) Klenow fragment is derived from large fragment of E. coli RNA polymerase I. (E) It is lack of 5’→3’ exonuclease activity.
82. Which of the following statements regarding β-oxidation of fatty acids is correct? (A) 16 acetyl-CoA molecules are produced by β-oxidation of palmitate. (B) One acetyl group is removed in one turn of β-oxidation. (C) In β-oxidation, ATP can be produced. (D) CO2 is generated by β-oxidation of palmitate. (E) The β-oxidation of unsaturated fatty acids has 4 basic steps.
83. Chartgraff's rules for DNA state that: (A) G+C = 39-46% in mammals (B) A=T and G=C (C) the sense strand is a right-handed helix (D) A=U and G=C (E) the minor groove is shallower than the major groove
84. Which of the following is a ribonucleoprotein required for the delivery of membrane and secretory proteins to the endoplasmic reticulum? (A) small ubiquitin-related modifier (SUMO) (B) signal recognition particles (SRP) (C) trigger factor (D) protein-conducting channel (PCC) (E) calnexin
85. Transcriptional activators that have variable positions and orientations are called _______. (A) enhancers (B) operators (C) introns (D) polycistrons (E) promoters
86. The peptide QYDG has a N-terminal _______ residue. (A) glutamic acid (B) glycine (C) glutamine (D) aspartic acid (E) alanine

87. The reaction below is catalyzed by yeast alcohol dehydrogenase. Which of the following corresponds to X and Y? (A) X = NAD + H+  Y = NADH+ (B) X = NADH + H+   Y = NAD+ (C) X = NADPH + H+  Y = NADP+ (D) X = NAD+   Y = NADH + H+ (E) X = NADH+   Y =NAD + H+
88. In E. coli, base-pairing between a mRNA's ______ and the 3' end of the 16S rRNA permits the ribosome to select the proper initiation codon. (A) 5' cap (B) Shine–Dalgarno sequence (C) poly( A ) tail (D) start codon (E) initiation factor
89. Chymotrypsin, a serine protease, preferentially cleaves a peptide bond adjoining a bulky non-polar side chain. This is because chymotrypsin's specificity pocket _______. (A) is mostly filled with large side chains (B) contains a negative charge (C) contains a positive charge (D) contains a sulfhydryl group that forms a disulfide bond with the substrate (E) is lined with small hydrophobic side chains, leaving considerable room in the nonpolar pocket
90. Oseltamivir (marketed as Tamiflu) has a structure mimicking ______, and thus is a strong inhibitor of neuraminidase of H1N1 influenza virus. (A) sialic acid (B) hyaluronic acid (C) sucrose (D) chondroitin sulfate (E) lactose

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