44.In plants, the climacteric is a stage of fruit ripening associated with increased production of which plant hormone?
(A) auxin
(B) abscisic acid
(C) cytokinin
(D) ethylene
(E) Gibberellin

39 Which of the following would you expect to be a problem for someone with nonfunctional chloride channeling? (A) inadequate secretion of mucus (B) buildup of excessive secretions in organs such as lungs (C) buildup of excessive secretions in glands such as the pancreas (D) sweat that includes no NaCl (E) mental retardation due to low salt levels in brain tissue

40. Plants often use changes in day length (photoperiod) to trigger events such as dormancy and flowering. It is logical that plants have evolved this mechanism because photoperiod changes (A) are more predictable than air temperature changes. (B) alter the amount of energy available to the plant. (C) are modified by soil temperature changes. (D) can reset the biological clock. (E) are correlated with moisture availability.

41.Which description of the lateral line system is false? (A) The lateral line system is found in amphibian larvae and fishes. (B) The lateral line system in fish can reflect pressure waves and low-frequency vibrations. (C) The lateral line system consists of hair cells within a longitudinal canal in the fish's skin. (D) The hair cells in the lateral line system are innervated by motor neurons that transmit impulses to the brain. (E) The hair cells' surface processes project into a gelatinous membrane called a cupula.

43. Plant cells and animal cells both evolve specialized conduits that directly connect the cytoplasm of two cells. What are they? (A) plasmodesmata in plant cells, desmotubules in animal cells (B) desmotubules in plant cells, plasmodesmata in animal cells (C) gap junctions in plants cells, plasmodesmata in animal cells (D) plasmodesmata in plant cells, gap junctions in animal cells (E) gap junctions in plant cells, desmotubule in animal cells

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.

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

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