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Chapter 21 (10E).Pdf Chapter 21 Student: ___________________________________________________________________________ 1. The genetic material that is found principally in the chromosomes is called: A.DNA B.RNA C.ADA D.NADH 2. Choose the following that is NOT accurate concerning deoxyribonucleic acid. A.It constitutes the major portion of chromosomes. B.It is found within the nucleus of eukaryotes. C.It can be found within mitochondria. D.It specifies the sequence of amino acids for protein synthesis. E.It contains a ribose sugar. 3. The bases in DNA are joined by hydrogen bonds and this association of complementary bases is called: A.nondisjunction B.pair bonding C.complementary base pairing D.replication 4. The process of making a copy of DNA is called: A.duplication B.replication C.isomerization D.transcription E.translation 1 5. DNA bases include all of the following except: A.adenine B.thymine C.cytosine D.uracil E.guanine 6. In complementary base pairing of the DNA molecule, adenine always combines with: A.adenine B.thymine C.cytosine D.uracil E.guanine 7. In complementary base pairing of the DNA molecule, cytosine always combines with: A.adenine B.thymine C.cytosine D.uracil E.guanine 8. Nucleotides are composed of: A.phosphate, base, protein B.sugar, protein, sulfur C.phosphate, sugar, base D.sugar, sulfur, phosphate 9. The best description for the overall shape (double helix) of the DNA molecule is: A.folded sheet B.twisted ladder C.stack of books D.string of beads 2 10. The enzyme which links nucleotides during DNA replication is: A.ACHase B.DNA polymerase C.nuclease D.protease 11. Mutations can be caused by: A.errors in the replication process B.exposure to environmental substances C.base substitutions D.All of the choices are correct. 12. Mutations are: A.changes in the base sequence within a gene B.always beneficial C.always harmful 13. In DNA function, the term "template" refers to: A.complementary RNA B.strand of DNA nucleotides which carries the information for amino acid order in a specific protein C.a chain of amino acids being transcribed from DNA 14. Which type of RNA forms the individual subunits of ribosomes? A.rRNA B.mRNA C.tRNA 15. Which type of RNA functions to bring in amino acids in the process of translation? A.rRNA B.mRNA C.tRNA 3 16. Which type of RNA carries the instructions from a template strand of DNA in the nucleus out to the ribosomes in the cytoplasm? A.rRNA B.mRNA C.tRNA 17. Choose the following base that is NOT associated with RNA. A.adenine B.thymine C.cytosine D.uracil E.guanine 18. Which of the following are paired bases in DNA? A.adenine—guanine; thymine—cytosine B.adenine—uracil; guanine—cytosine C.adenine—thymine; guanine—cytosine D.adenine—adenine; guanine—guanine E.adenine—cytosine; guanine—thymine 19. In DNA, the amount of adenine is always equal to the amount of: A.cytosine B.uracil C.guanine D.thymine E.ATP 20. A nucleotide contains: A.DNA and RNA B.a sugar, a phosphate, and a base C.RNA, protein, and lipids D.a sugar, a phosphate, and an amino acid 4 21. In the model of DNA, the "rungs" of the ladder are composed of: A.sugars B.paired bases C.phosphates D.a sugar and a phosphate molecule 22. If 30% of an organism's DNA is thymine, then: A.70% is deoxyribose B.20% is guanine C.20% is adenine D.40% is guanine 23. In a DNA molecule, the: A.backbone is composed of covalently bonded bases B.sugars are composed of 8 carbon rings C.bases are hydrogen bonded to one another D.adenine and cytosine base pair to each other 24. Which of the following contains thymine? A.DNA B.mRNA C.rRNA D.protein E.tRNA 25. In DNA, what makes up the "sides" of the ladder? A.sugar-phosphate backbone B.adenine-phosphate backbone C.base-phosphate backbone D.sugar-sugar backbone 5 26. Which of the following is NOT true about DNA? A.It forms a double helix. B.Bases are held together by hydrogen bonds. C.Bases form complementary pairs. D.It has a deoxyribose sugar. E.It contains adenine, guanine, cytosine, and uracil. 27. Which of the following is NOT true about mRNA? A.It is found in the cytoplasm. B.It contains the sugar ribose. C.It contains adenine, guanine, uracil, cytosine. D.It is single-stranded. E.It forms a double-stranded helix. 28. During DNA replication: A.each base forms hydrogen bonds with a complementary base B.each base forms hydrogen bonds with the same type of base C.bases do not form hydrogen bonds D.ribose is incorporated into the double helix 29. In normal transcription DNA serves as a template for the synthesis of: A.more DNA B.messenger RNA C.enzymes D.DNA polymerase 30. In replication DNA serves as a template for the synthesis of: A.more DNA B.messenger RNA C.enzymes D.DNA polymerase 6 31. The enzyme that joins DNA complementary nucleotides together is: A.DNA polymerase B.RNA polymerase C.helicase D.ribozyme E.lipase 32. DNA is: A.transcribed B.translated 33. Which of the following carries a copy of DNA's blueprint into the cytoplasm? A.tRNA B.rRNA C.mRNA D.cDNA 34. The site of protein synthesis in eukaryotes is: A.the nucleus B.the plasma membrane C.the ribosome D.the mitochondria 35. Every three base code on DNA (a triplet) codes for a single: A.carbohydrate monomer B.lipid polymer C.amino acid D.nucleic acid 36. A three letter (base) code on the DNA is called: A.triplet B.codon C.anticodon D.triumvirate 7 37. The universal genetic code describes the fact that: A.all complementary base pairs align the same way B.the same codons always stand for the same amino acids C.transcription always follows translation D.many organisms have the same proteins 38. A section of DNA that codes for a protein is, by definition, a: A.a mutation B.a base pair C.a gene D.a chromatid 39. 39.The bases of DNA form what we can think of as "code words" representing the different amino acids. Each "code word" is composed of: A.a triplet of nitrogen bases B.a triplet of amino acids C.2 nitrogen bases D.a single nitrogen base 40. Bases of mRNA that are complementary to a triplet of bases of template DNA are called: A.an anticodon B.a codon C.a counter codon 41. The three exposed unpaired bases on a tRNA molecule are called: A.an anticodon B.a codon C.a counter codon 42. Transcribed segments of DNA which contain coded information are called: A.introns B.exons 8 43. The synthesis of a polypeptide chain under the direction of the mRNA molecule is called: A.transcription B.translation C.transduction D.transformation 44. If the codon (on the mRNA) is ACC, then the anticodon (on the tRNA) is: A.UGA B.UGG C.TGG D.CAA E.None of the choices are correct. 45. In translation, termination of synthesis occurs at: A.the codon for the amino acid valine B.the codon for 'stop' which does not code for an amino acid C.a special 4-base codon D.the special 4-base codon for valine 46. Synthesis of polypeptides requires: A.initiation B.elongation C.termination D.All of the choices are correct. 47. Several ribosomes, collectively, are called: A.multisomes B.polyribosomes C.oligosomes D.deuterosomes 9 48. The primary level of control for gene expression that functions to turn on only selected genes within the nucleus is called: A.transcriptional control B.posttranscriptional control C.translational control D.posttranslational control 49. During cell division, the genetic material: A.stores new information B.is replicated C.undergoes rare mutations D.is sequestered in the cytoplasm 50. If one strand of DNA has the base sequence ATCGTA, what will the complementary strand have? A.TAGCAT B.ATCGTA C.CAGTCT D.ATGCTA 51. Before protein synthesis, DNA: A.attracts tRNAs with appropriate amino acids B.serves as a template for the production of mRNA C.adheres to ribosomes for protein synthesis D.contains anticodons that become codons E.All of the choices are correct. 52. The triplet code consists of ___ bases that designate one amino acid. A.2 B.3 C.4 D.8 E.20 10 53. Transcription of part of a DNA molecule with a nucleotide sequence of AAACAACTT results in an mRNA molecule with which complementary sequence? A.GGGAACC B.UUUGUUGAA C.TTTGAAGCC D.CCCACCTCC 54. Transcription takes place: A.in the nucleus B.in the cytoplasm C.on free ribosomes D.in the rough endoplasmic reticulum 55. Translation takes place: A.in the nucleus B.outside the cell C.on ribosomes D.in the mitochondria 56. The function of transfer RNA is to: A.carry amino acids to ribosomal sites B.transfer nucleotides to the nucleus C.transmit coded information to the cytoplasm D.turn the DNA on and off E.All of the choices are correct. 57. A primary mRNA molecule becomes a mature mRNA molecule following: A.capping one end with an altered guanine nucleotide B.poly-A tail is added to one end C.introns are removed D.All of the choices are correct. 11 58. The term "triplet code" is a code for a(n): A.nucleotide unit B.nucleic acid C.amino acid D.fatty acid 59. Which of the following carries amino acids to ribosomal sites? A.DNA B.mRNA C.rRNA D.protein E.tRNA 60.
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