34. Why do RNA viruses appear to have higher rates of mutation?
(A) RNA viruses are more sensitive to mutagens.
(B) RNA viruses can incorporate a variety of nonstandard bases.
(C) RNA viruses replicate faster.
(D) Replication of their genomes does not involve the proofreading steps of DNA replication.
(E) RNA nucleotides are more unstable than DNA nucleotides.

30. Which statement is TRUE? (A) A higher Km value indicates a higher substrate specificity. (B) A higher Km value indicates a higher substrate affinity. (C) The unit for Km is M-1 s -1 . (D) kcat is the specificity constant. (E) kcat/Km is a measure of enzyme efficiency.

31. Which description about interaction between species is NOT true? (A) Predation: An individual of one species, the predator, kills and eats an individual of the other, the prey. (B) Parasitism: The parasite obtains its nourishment from a second organism, its host. (C) Competition: Indivisuals of different species each use a limited resourse, reducing the survival or reproductin of both individuals. (D) Commensalism: Members of both species benefit from the interaction. (E) Herbivory: An herbivore eats part of a plant or alga.

32. Fungal cells can reproduce asexually by undergoing mitosis, followed by cytokinesis. Many fungi can also reproduce sexually by undergoing ______. (A) cytokinesis followed by karyokinesis (B) binary fission followed by cytokinesis (C) plasmolysis followed by karyotyping (D) plasmogamy followed by karyogamy (E) sporogenesis followed by gametogenesis

33. Which is a TRUE statement concerning genetic variation? (A) It is created by the direct action of natural selection. (B) It arises in response to changes in the environment. (C) It must be present in a population before natural selection can act upon the population. (D) It tends to be reduced by the processes involved when diploid organisms produce gametes. (E) A population that has a higher average heterozygosity has less genetic variation than one with a larger average heterozygosity.

35. To prevent irreversible tragedies, the CDC urges the public not to use blood donation as a means of Human immunodeficiency virus (HIV) testing, as there is a period for HIV infection. (A) prophase (B) infectious (C) latency (D) anaphase (E) telophase

36. Which of the following characters is NOT a terrestrial adaptation of plants? (A) Waxy stomata to reduce water loss (B) Vascular tissue in most plants to transport water/sugar within the plant (C) Specialization within the plant with root/shoot (D) Spore/seed for dispersal (E) Flagellated sperm

37. Which of the following genetic changes of K-Ras is detected in over 90% of human pancreatic cancers? (A) Translocation (B) Mutation (C) Promoter methylation (D) Amplification (E) Transposition

38. In the process of human gametogenesis, which cell is haploid? (A) Spermatogonium (B) Primary spermatocyte (C) Primary oocyte (D) Early spermatid (E) Oogonium

39. In humans, the phenylalanine hydroxylase gene is 90,000 bases (90 kb) long, yet the mRNA is only 2,400 bases (2.4 kb). What explains this difference? (A) RNA editing (B) Code for poly A tail that is removed in mRNA (C) Loss of stability without a 5’ cap (D) Removal of exons in the final mRNA (E) Presence of introns in DNA

40. Which of the following organelles CANNOT be found in animal cells? (A) Lysosome (B) Central vacuole (C) Mitochondrion (D) Peroxisome (E) Centriole