59. Which of the following best represents the path of a signal that causes muscle contraction?
(A) motor neuron→sarcoplasmic reticulum→sarcolemma→transverse tubules
(B) transverse tubules→sarcoplasmic reticulum→sarcolemma→motor neuron
(C) motor neuron→transverse tubules→sarcolemma→sarcoplasmic reticulum
(D) sarcoplasmic reticulum→transverse tubules→sarcolemma→motor neuron
(E) motor neuron→sarcolemma→transverse tubules→sarcoplasmic reticulum

55. The brain perceives the brightness of light by sensing (A) the voltage of action potentials in the optic nerve (B) the frequency of action potentials in the optic nerve (C) which specific rod cells are stimulated (D) how many hair cells are stimulated (E) action potentials from brightness-sensing neurons

56. In what symptoms may be resulted by damage to the corpus callosum? (A) loss of short-term memory (B) inability to integrate information from the two sides of the body (C) inability to form long-term memory (D) sleeplessness (E) loss of fine motor control

57. What does the Hardy-Weinberg expression 2pq represent? (A) the gene frequency of the dominant allele (B) the gene frequency of the recessive allele (C) the frequency of the dominant phenotype (D) the frequency of the recessive phenotype (E) the frequency of heterozygotes

58. Which developmental sequence is correct? (A) fertilization→gastrulation→blastula formation→morula formation→cleavage (B) cleavage→fertilization→blastula formation→momla formation→gastmlation (C) fertilization→cleavage→blastula formation→morula formation→gastralation (D) fertilization→cleavage→morula formation—blastula formation→gastrulation (E) fertilization→cleavage→momla formation→gastmlation→blastula formation .

60. What prevents an action potential from propagating in both directions along an axon? (A) During the refractory period, a patch of membrane cannot conduct another action potential. (B) The sodium channels allow the passage of ions in only one direction. (C) ATP stores are temporarily exhausted following an action potential. (D)The sodium-potassium pumps are temporarily disabled by an action potential. (E) All of the above

61. in the atmosphere, the partial pressure of oxygen is 0.21 atmosphere; of carbon dioxide, 0.0003. Which of the following statements is not true? (A)The partial pressure of oxygen in lung capillary is greater than 0.21. (B) In the pulmonary vein, the partial pressure of oxygen is greater than in the inferior vena cava. , (C) In the pulmonary artery, the partial pressure of carbon dioxide is greater than 0.0003. (D) The partial pressure of oxygen in muscle capillaries is less than 0.21. (E) In the renal artery, the partial pressure of oxygen is greater than in the renal vein.

62. The following sequence shows a “gene” encoding a small peptide. The three stop codons are UAA, UAG, and UGA. How many amino acids will be encoded by this “gene”？ The promoter region is underlined. 5' (ATGACGTATAA)TGACCGTACATGAGTAATACATAAATGAG3'(A) 4 (B)5 (C)7 (D)8 (E) 12

63. Which of the following statements regarding transposons is false? (A)Transposons have a specific target site within the genome. (B) Transponses are found in both prokaryotes and eukaryotes. ' (C) Transposons can move from a plasmid to the chromosome of the bacterium. (D) Transposons may replicate at the original site and insert the copy at another site. (E) Transposons may cany only the genes necessary for insertion.

64. Which of the following statements is correct about Gram-negative bacteria? (A) Penicillins are effective antibiotics against them. (B) They often possess an outer cell membrane containing toxic lipopolysaccharides. (C) On cell-to-cell basis, they possess more DNA than the cells of any taxonomically higher organism do. (D) Their chromosomes are composed of DNA tightly wrapped around hi stone protein. (E) Their cell walls are primarily composed of peptidoglycan.

65. Which of the following statements is true about arteries? (A) arteries always carry deoxygenated blood (B) arteries always carry oxygenated blood (C) arteries always carry blood toward the heart (D) arteries always carry blood away from the eart (E) B and D