57. The frequency of antibiotic resistance increases in human populations which is the result of:
(A) balancing selection.
(B) disruptive selection.
(C) directional selection.
(D) sexual selection.
(E) stabilizing selection.

53. A drug might act as a stimulant of the somatic nervous system if it (A) increases the sensitivity of the postsynaptic membrane to acetylcholine. (B) increases the release of substances that cause the hyperpolarization of the neurons. (C) stimulates the activity of acetylcholinesterase in the synaptic cleft. (D) makes the membrane permanently impermeable to sodium. (E) increases the sensitivity of the presynaptic membrane to acetylcholine.

54. Which of the following word pairs are MISMATCHED? (A) Random distribution: aggressive interaction. (B) Clumped distribution: attraction to a common source. (C) Regular distribution: antagonistic behaviors. (D) Large scale distribution: substantial environmental changes. (E) Small scale distribution: insignificant environmental changes.

55. Why would a scientist choose to use DNA analysis rather than isozyme analysis when investigating genetic variations? (A) Smaller sample size can be used for DNA analysis. (B) Repeat sampling over a period of time is possible. (C) Non-injurious to the organism. (D) Non-lethal. (E) All of the choices are correct.

56. Which of the following ecosystems has the highest net primary production (g/m2/yr): (A) Estuary. (B) Swamp and marsh. (C) Algal beds and reefs. (D) Tropical rain forest. (E) Temperate deciduous forest.

58. Bioinformatics is the application of computational methods to the storage and analysis of enormous volumes of biological data. What is the BLAST program in NCBI which has been described by many biologists as the single most important tool in bioinformatics? (A) It is the tool to find out ESTs (expressed sequence tags). (B) It is the tool to figure out the protein-protein interaction. (C) It is the tool to translate the coding sequence. (D) It is the tool to align the sequences. (E) It is the tool to look the protein 3D structure.

59. Which of the following enzyme(s) is/are involved in the human nucleotide excision repair of UV-induced pyrimidine dimers? 1. endonucleases 2. DNA ligase 3. DNA polymerase 4. photoreactivating enzyme (DNA photolyase) (A) 1. (B) 1 and 3. (C) 2 and 4. (D) 1, 2 and 3. (E) All of them. .

60. Which of the following statement regarding the transcription initiation and RNA Pol I is NOT true? (A) The regulatory sequences include a core element and an upstream element. (B) RNA Pol I is responsible for synthesizing tRNAs and 5S-rRNA. (C) An active Pol I initiation complex contains multi-protein complexes assembled in order. (D) RNA Pol I is responsible for synthesizing rRNA. (E) RNA Pol I itself is a multi-subunit complex.

61. Which of the following is NOT a characteristic of microRNAs? (A) MicroRNAs are found in eukaryotes including animals and plants. (B) MicroRNAs regulate gene expression by degradation of specific mRNAs. (C) MicroRNAs regulate gene expression by translational inhibition of specific mRNAs. (D) MicroRNAs usually act as negative regulator of gene expression. (E) MicroRNAs can function when they are short double-stranded RNA.

62. Stigmasterol, ergosterol, bile acids, vitamin D, cholesterol and share all the following common features EXCEPT (A) four-ring structure. (B) a carboxylic acid group. (C) contain asymmetric structure. (D) an extending carbon chain derived from the ring structure. (E) a hydroxyl group on first ring.

63. Meiosis is a special type of cell division. Which of the following mechanism(s) occur during meiosis guarantees that each haploid germ cell will have a unique combination of gene alleles that is distinct from each parent as well as every other haploid germ cell generated? (A) Recombination. (B) Reassortment. (C) Duplication. (D) A and B. (E) A, B and C.