48. In the formation of a blood clot, damaged cells and platelets release substances which catalyze the conversion of
(A) fibrinogen to fibrin
(B) fibrin to fibrinogen
(C) prothrombin to thrombin
(D) thrombin to prothrombin
(E) thrombin to fibrin

44. Breathing rate increases because of (A) insufficient oxygen in the blood (B) excess carbon dioxide in the blood (C) the accumulation of metabolites in the blood (D) both A and B (E) all of A, B, and C

45. Which of the following vitamins is incorrectly associated with its use? (A) vitamin B2: component of coenzymes NAD+ and NADP+ (B) folic acid: coenzyme in nucleic acid and amino acid metabolism (C) vitamin C: used in collagen synthesis (D) vitamin A: component of visual pigments (E) vitamin K: important in blood clotting

46. Which of the following areas of study examines energy flow and chemical cycling between organisms and the environment? (A) population ecology (B) community ecology (C) ecosystem ecology (D) landscape ecology (E) global ecology

47. What is the target organ for thyrotropin-releasing hormone? (A) hypothalamus (B) anterior pituitary (C) posterior pituitary (D) thyroid (E) liver

49. Phosphatidylinositol 4,5-bisphosphate (PIP2) is cleaved by phospholipase C into (A) 1,2-diacylglycerol (DAG) (B) phosphatidylinositol (PI) (C) inositol 1,4,5-trisphosphate (IP3) (D) A and C (E) B and C

50. The correct sequence, from the most to the least comprehensive, of the taxonomic levels listed here is (A) kingdom, domain, phylum, class, order, and family (B) domain, kingdom, phylum, class, order, and family (C) kingdom, domain, phylum, class, family, and order (D) kingdom, phylum, domain, class, family, and order (E) kingdom, phylum, domain, class, family, and order 

51. Which of the following statement about plant flower is correct? (A) A flower is the vegetative organ of a plant. (B) A flower lacking any of sepal, petal, stamen or carpel is an imperfect flower. (C) Most grasses have imperfect flowers. (D) Floral parts in all angiosperm are arranged as four whorls. (E) Floral parts are sequentially initiated at the floral meristem.

52. A larvae of certain fly lives on body surface of a dog feeding on host’s skin. What will be the ecological position of this creature? (A) primary consumer (B) secondary consumer (C) tertiary consumer (D) producer (E) decomposer

53. When we refer to a plant as a “short-day plant”, we mean that _____. (A) the plant flowers in winter (B) the plant flowers when day is shorter than 12 hours (C) the plant flowers only in the equator area (D) the plant flowers when the night is longer than its own critical night length (E) both A and D 

54. Which of the following statements regarding photosynthesis is FALSE? (A) The principal electron carrier in photosynthesis is NADPH; the principal electron carrier in respiration is NADH. (B) The light reactions occur in the stroma, while the Calvin cycle occurs in the thylakoid membranes. (C) The light reactions of photosynthesis can produce ATP, NADPH and O2. (D) Sunlight is a type of electromagnetic energy. (E) Chlorophyll a reflects green light.