資訊推薦

• 17. If there are 20 chromatids in a cell at metaphase, how many chromosomes are there in each daught
• 18. Which of the following occurs in meiosis but not in mitosis?(A) Chromosome replication(B) Synaps
• 19. Homologous chromosomes synapse and crossing over occurs(A) The statement is true for mitosis onl
• 20. Which of the following happens at the conclusion of meiosis I?(A) Homologous chromosomes are sep
• 21. In certain plants, tall is dominant to short. If a heterozygous plant is crossed with a homozygo
• 22. In a cross AaBbCc × AaBbCc, what is the probability of producing the genotype AABBCC?(A) 1/8(B)
• 23. Mendel was able to draw his ideas of segregation and independent assortment because of the influ
• 24. Skin color in a certain species of fish is inherited via a single gene with four different allel
• 25. Calico cats are female because(A) a male inherits only one of the two X-linked genes controlling
• 26. If a human interphase nucleus contains three Barr bodies, it can be assumed that the person(A) h
• 27. A cell that has 2n + 1 chromosomes is(A) trisomic(B) monosomic(C) euploid(D) polyploid
• 28. In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made us
• 29. Which enzyme catalyzes the elongation of a DNA strand in the 5' → 3' direction?(A) pri
• 30. Which component is not directly involved in translation?(A) mRNA(B) DNA(C) tRNA(D) ribosomes
• 31. Which of the following is not true of RNA processing?(A) Exons are cut out before mRNA leaves th
• 32. Sickle-cell disease is probably the result of which kind of mutation?(A) point(B) frameshift(C)
• 33. What are polyribosomes?(A) groups of ribosomes reading a single mRNA simultaneously(B) ribosomes
• 34. The role of a metabolite that controls a repressible operon is to(A) bind to the promoter region
• 35. Genomic imprinting, DNA methylation, and histone acetylation are all examples of(A) genetic muta
• 36. In both eukaryotes and prokaryotes, gene expression is primarily regulated at the level of(A) tr
• 37. The host range of a virus is determined by(A) the proteins on its surface and that of the host(B
• 38. What is the function of reverse transcriptase in retroviruses?(A) It hydrolyzes the host cell�
• 39. What are prions?(A) misfolded versions of normal brain protein(B) tiny molecules of RNA that inf
• 40. What is the name given to viruses that are single-stranded RNA that acts as a template for DNA s
• 41. What is the enzymatic function of restriction enzymes?(A) to add new nucleotides to the growing