資訊推薦

• 41. The two main stages of the eukaryote cell cycle, in which the cell spends most of its time and m
• 42. The structure that organizes the protein subunits of the mitotic spindle is the__? (A) centrosom
• 43. How does the space between our fingers arise? (A) Mitosis of the cells is blocked；(B) The cells
• 44. In order for a cell to become cancerous, oncogenes must be ___, or tumor suppressors are ___. (A
• 45. Diploid means having__? (A) the somatic cells have all chromosomes except the sex chromosomes；(B
• 46. In a cell dividing by meiosis, DNA is replicated__? (A) between meiosis I and again before meios
• 47. In meiosis, homologous chromosomes align next to one another during__? (A) prophase I；(B) propha
• 48. If the heterozygous phenotype is intermediate between those of the two different homozygotes, th
• 49. Linked genes, by definition, are genes that__? (A) have no alleles；(B) have more alleles than us
• 50. A single chromosome has__? (A) a single gene with multiple alleles；(B) a single gene with a sing
• 51. The method used to produce the cloned sheep, Dolly, was__? (A) embryonic stem cell transplantati
• 52. Darwin concluded from his observations of nature and readings that__? (A) population growth is u
• 53. Natural selection acts on__? (A) genotypes；(B) populations；(C) individuals；(D) communities.
• 54. If similarities between two structures in different organisms reflect independent evolution, the
• 55. The observation that most aquatic vertebrates (e.g. fish, penguins, and whales) have streamlined
• 56. The enzyme that HIV uses to copy its RNA into DNA is__? (A) Reverse transcriptase；(B) RNA polyme
• 57. A vaccine against the influenza virus would result in production of antibodies against which of
• 58. Viruses always lack which of the following? (A)an envelope；(B) organelles；(C) genetic material；(
• 59. A microbiologist Gram stains a bacterium and finds the bacterium to be pink to red in color, thi
• 60. Escherichia coli and Salmonella can live in our intestines in the presence or absence of oxygen.
• 61. A gaseous hormone produced by plants that helps control fruit ripening is__? (A) dextrose；(B) ca
• 62. If a plant exhibits determinate growth, the plant__? (A) produces auxiliary roots to help stabil
• 63. The _____ transports water and dissolved minerals from the roots of the plant to the shoots of t
• 64. The _____ and _____ of a plant's leaf help conserve water in a plant. (A) root hairs； stoma
• 65. If water is abundant, a plant's guard cells will____ and the stomata will_____. (A) swell；