33. Which of the following characteristics best describes the urea cycle?
(A) All of the enzymes are localized in the cytosol of hepatocytes.
(B) The enzymes are present in high concentration in the perivenous hepatocytes.
(C) Arginine is the end product of the urea cycle.
(D) The cleavage of argininosuccinate releases fumarate.
(E) Asparagine is a substrate in the urea cycle.

29. A Taiwan ecologist monitoring the number of Formosan macaque in a wildlife refuge over a 10-year period is studying ecology at which level? (A) population (B) ecosystem (C) organism (D) community (E) biosphere

30. Which of the following characteristics best describes specialized cell junction? (A) Adherens junctions but not desmosomes are the main types of anchoring junctions. (B) Gap junctions prevent the movement of molecules across cell layers. (C) Tight junctions allow direct electrical and chemical communication between cells. (D) Plasmodesmata permit direct cell-cell communication between plant cells. (E) Tight junctions are the main types of communicating junctions between cardiac muscle cells.

31. Which of the following sources of reducing equivalents is most important for steroid hormone synthesis? (A) glycolysis (B) tricarboxylic acid (TCA) cycle (C) malate shuttle (D) fatty acid oxidation (E) pentose phosphate pathway

32. Which of the following statements about gout is true? (A) It results from the overproduction of orotic acid. (B) It can result from a deficiency in phosphoribosylpyrophosphate (PRPP) synthetase. (C) It can be treated with inhibitors of xanthine oxidase. (D) It occurs more frequently in women than men. (E) The symptoms appear in early adolescence. 

34. Which of the following vitamins involves primarily in transamination reactions of amino acid metabolism? (A) Vitamin C (B) Vitamin E (C) Vitamin B6 (D) Vitamin B12 (E) Vitamin A

35. Martin and Mary have free earlobes, but their son Mark does not. If Martin and Mary have two more children, what is the probability that both will have attached earlobes? (A) 1/4 (B) 3/4 (C) 1/16 (D) 9/16 (E) 3/16

36. Which of these statements best describes stem cells? (A) Adult stem cells but not embryonic stem cells are immortal in lab culture. (B) Only embryonic stem cells are found in every tissue of the adult body. (C) Embryonic stem cells and induced pluripotent stem cells give rise to all the different types of cells in the organism. (D) Stem cells can be isolated from the inner cell mass of blastocytes, bone marrow, and amniotic fluid, but not from adipose tissues. (E) Cancer stem cells possess characteristics associated with normal stem cells.

37. Which order is correct according to the number of genes from big to small in the following organisms? 1. E. coli 2. Rice 3. Human sperm 4. D. melanogaster (Fruit fly) 5. Saccharomyces cerevisiae (yeast) (A) 23451 (B) 24351 (C) 34251 (D) 32415 (E) 34521

38. Phenylketonuria (PKU) is due to a recessive allele. Given 1 PKU occurrence per 25 births, what is the frequency of individuals with the heterozygous phenotype if the population is in Hardy-Weinberg equilibrium? (A) 0.2 (B) 0.32 (C) 0.64 (D) 0.8 (E) 0.96

39. Which of these statements best describes speciation? (A) Populations separated by a geographic barrier are known as sympatric populations. (B) Geographic isolation necessarily leads to new species. (C) For allopatric speciation to occur, changes in the gene pool must produce reproductive isolation. (D) In allopatric speciation, reproductive isolation develops and new species arises without geographic separation. (E) A small population is less likely to have its gene pool changed by genetic drift and natural selection.