49. When DNA is compacted by histones into 10 nm and 30 nm fibers, the DNA is unable to interact with proteins required for gene expression. Therefore, to allow for these proteins to act, the chromatin must constantly alter its structure. Which processes contribute to this dynamic activity?
(A) DNA supercoiling at or around Hl
(B) methylation and phosphorylation of histone tails
(C) hydrolysis of DNA molecules where they are wrapped around the nucleosome core
(D) accessibility of heterochromatin to phosphorylating enzymes
(E) nucleotide excision and reconstruction

45. In humans, ABO blood types refer to glycoproteins in the membranes of red blood cells. There are three alleles for this autosomal gene: IA, IB, and i. The LA allele codes for the A glycoprotein, The IB allele codes for the B glycoprotein, and the i allele doesn't code for any membrane glycoprotein. IA and IB are codominant, and i is recessive to both IA and IB. People with type A blood have the genotypes IAIA or IAi, people with type B blood are IBIB or IBi, people with type AB blood are IAIB, and people with type O blood are it. If a woman with type B blood marries a man with type A blood, which of the following blood types could their children possibly have? (A) A and B (B) AB and O (C) A, B, and AB (D) A, B, and O (E) A, B, AB, and O

46. How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes? (A) It adds numerous GC pairs, which resist hydrolysis and maintain chromosome integrity. (B) It catalyzes the shortening of telomeres, compensating for the elongation that could occur during replication without telomerase activity. (C) It adds a single 5' cap structure that resists degradation by nucleases. (D) It is a reverse transcriptase that carries its own RNA molecule that works as a template to lengthen telomeres. (E) It causes specific double-strand DNA breaks that result in blunt ends on both strands.

47. Which of the following enzymes is the most abundant protein in the chloroplast and incorporates CO2 molecules to ribulose diphosphate? (A) Aldolase (B) Rubisco (C) Phosphoglycerate kinase (D) Triose phosphate isomerase (E) Glyceraldehyde 3-phosphate dehydrogenase

48. Several adaptations that facilitate survival and reproduction on dry land emerged after plants diverged from algal. Which of the following traits is found in plants but not in charophyte algae? (A) Alternation of generations. (B) Chloroplasts with chlorophylls a and b. (C) Circular rings of cellulose-synthesizing proteins. (D) Flagellated sperm. (E) Sporopollenin in zygotes.

50.Some viruses can undergo latency, the ability to remain inactive for some period of time. Which of the following is an example? (A) influenza, a particular strain of which returns every 10-20 years (B) herpes simplex viruses (oral or genital) whose reproduction is triggered by physiological or emotional stress in the host (C) Kaposi's sarcoma, which causes a skin cancer in people with AIDS, but rarely in those not infected (D) the virus that causes a form of the common cold, which recurs in patients many times in their lives (E) myasthenia gravis, an autoimmune disease that blocks muscle contraction from time to time

複選題複選題 51.Which of the following regarding the human viral disease is false? (A)(B)(C)(D)(E)

52.What period of the malaria parasite (Plasmodium malariae) is not inside the human body? (A) schizont (B) trophozoite (C)oocyst (D) merozoite (E) sporozoite by HIV viruses

53.Which of the following statements regarding abscisic acid (ABA) is false? (A) ABA is a plant-specific hormone and does not found in human body. (B) It is a 15-carbon weak acid terpenoid hormone. (C) It is found in high concentrations in newly abscissed leaves. (D) ABA accumulates within seeds during fruit maturation thus preventing premature seed germination. (E) it is synthesized from carotenoids in a series of reactions in plastids and cytoplasm.

54. A pilus (plural: pili) is a hair like structure found on the surface of many bacteria. Which of the following statements regarding pilus is false? (A) It is made of pilin. (B) It participates in the process of bacterial conjugation. (C) Pili are responsible for virulence in many pathogenic strains of bacteria. (D) Pili can protect bacterial cells against bacteriophage. (E) Pili are antigenic.

55. The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including those in their original homeland. Which of the following mechanisms likely explains the genetic uniqueness of this population? (A) mutation and natural selection (B) founder effect and genetic drift (C) disassortative mating and divergent selection (D) population bottleneck and Hardy-Weinberg equilibrium (E) heterozygote advantage and stabilizing selection