45. Fermentation is essentially glycolysis plus an extra step in which pyruvic acid is reduced to form lactic acid or alcohol ; and carbon dioxide. This last step 養
(A) removes poisonous oxygen from the environment
(B) extracts a bit more energy from glucose [
(C) enables the cell to recycle NAD+
(D) inactivates toxic pyruvic acid
(E) enables the cell to make pyruvic acid 奪 into substances it can use [

41. A graduate student growing plant cells in a laboratory dish wanted to cause them to _, so the graduate student j treated them with cytokinins. I (A) enlarge (B) become dormant (C) grow roots (D) produce auxins (E) divide 量

42. Which of the following structures is incorrectly paired with its function? (A) epididymis - maturation and storage of sperm  (B) uterus — fertilization of an egg (C) seminal vesicles — add sugar and mucus to semen  (D) placenta - matemal/fetal exchange organ; progesterone producing (E) prostate gland — adds alkaline substances to semen

43. An area of habitat where a population's reproductive success exceeds mortality is (A) the results of edge effect (B) going to occur speciation very soon (C) a source habitat to the population (D) going to decrease population size (E) the effective size of the population

44. Which of the following is an INCORRECT statement about fungi? (A) they are heterotrophs (B) most of their bodies are constructed of hyphae : (C) their cell walls mainly consist of cellulose (D) they are more closely related to animals than plants (E) they serve as decomposers in communities £

46. A biologist isolated a gene from a human cell, attached it to a plasmid, and inserted the plasmid into a bacterium. The I； bacterium made a new protein, but it was nothing like the protein normally produced in a human cell. Why? ; (A) the bacterium had undergone transformation (B) the gene did not have sticky ends 誓 (C) the gene contained introns (D) the gene did not come from a genomic library ; (E) the biologist should have cloned the gene first ^

47. During kidney dialysis, blood and a dialyzing solution are separated by a semipermeable membrane. For kidney dialysis to work properly, the dialyzing solution should contain  (A) a lower solute concentration than blood (B) a higher concentration of urea than blood  (C) a lower glucose concentration than blood (D) a lower concentration of urea than blood  (E) a much smaller volume of fluid than the blood passing through it 

48. It takes much longer for sex hormones and other steroids to produce their effects than it takes for nonsteroid hormones. ; Why? | (A) steroids are bigger, slower molecules (B) steroids usually must be carried longer distances by the blood ^ (C) steroids cause target cells to make new proteins, which takes time (D) steroids must relay their message via a ; second messenger (E) it takes longer for endocrine cells to make and secrete steroids ^

49. A peak in_triggers ovulation on about the_day of the monthly cycle. [ (A) progesterone ... fourteenth (B) LH ... seventh (C) FSH ... second (D) LH .. .fourteenth | (E) estrogen ... twentieth

50. Mitosis and cytokinesis result in the formation of_, meiosis and cytokinesis result in the formation of_. (A) 4 diploid cells ... 4 haploid cells (B) 2 diploid cells …2 hap]oid cells (C) 2 diploid cells ... 4 haploid cells | (D) 2 diploid cells ...2 diploid cells (E) 4 haploid cells ...2 diploid cells |：

51. During the early development of a human embryo the_________eventually forms_________. (A) blastocoel ... arch enter on (B) epiblast...ectodermal, mesodermal, and endodermal tissues (C) epiblast... placenta (D) trophoblast... embryo proper (E) hypoblast ... amniotic cavity