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.

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

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

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 

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.

55. Which of the following statements about gas exchange is FALSE? (A) Breathing control centers are located in parts of the brain called the cerebellum and medulla oblongata. (B) The control center regulates breathing rate in response to changes in the CO2 level of the blood. (C) Gills are unsuitable for animals living on land because the large surface area of gills would allow dehydration of the animal. (D) Unlike the tracheal system of insects, vertebrate lungs are restricted to one location in the body. (E) Medullary breathing centers directly sense and respond to blood pH and CO2 concentration.

56. Which of the following statements is FALSE? (A) Speciation, or the formation of new species, is the bridge between microevolution and macroevolution. (B) The likelihood of allopatric speciation increases when a splinter population is small and isolated from the broader range of the species. (C) Speciation without geographic isolation is called allopatric speciation. (D) Organisms carry more than two complete sets of chromosomes in are called as polyploid. (E) Most polyploid species arise from the hybridization of two parent species and subsequent chromosome duplications.

57. Mammalian Toll-like receptors (TLRs) recognize macromolecules present on certain groups of pathogens. Which of the following is most likely to be recognized by TLR that defends against certain viruses? (A) lipopolysaccharides (B) double-stranded peptide (C) double-stranded RNA (D) gylcoproteins (E) phosphopeptides