DNA TEST REVIEW

KEY TERMS

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  1. Antiparallel
  2. Bacteriophages
  3. Chargaff’s rules
  4. complementary
  5. DNA polymerase
  6. Double helix
  7. Excision repair
  8. Exonuclease
  9. Genes
  10. Helicase
  11. Lagging strand
  12. Leading strand
  13. Ligase
  14. Mutagen
  15. Nuclease
  16. Nucleic acid
  17. Nucleotide
  18. Okazaki fragments
  19. Phosphodiester bond
  20. Purine
  21. Pyrimidine
  22. Replication fork
  23. replisome
  24. Semiconservative
  25. Supercoiling
  26. Telomeres
  27. Thymine dimer
  28. Topoisomerase
  29. Transformation

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1. Describe the experiments of the following people and what they contributed to the understanding of DNA.

Frederick Griffith

Oswald Avery

Hershey and Chase

Rosalind Franklin

Erwin Chargaff

Watson and Crick

2. Summarize the evidence and techniques Watson and Crick used to deduce the double helix structure of DNA.

3. Review your understanding of DNA replication by describing the key enzymes and proteins (in order of their functioning) that direct replication.

4. Transformation involves

a. the uptake of external genetic material.

b. the creation of a strand of RNA from a DNA molecule.

c. infection of bacterial cells by a phage

d. the type of semiconservative replication shown by DNA.

5. The DNA of an organism has thymine as 20% of its bases. What percentage would be guanine?

6. Which of the following most closely represents Chargaff’s rule?

a. A pairs with T and C pairs with G

b. %A +%T = %C+%G

c. %A +%G = %C+%T

d. Strands in a DNA double helix are antiparallel.

7. DNA polymerase is not able to bind copying a DNA strand on its own. How is the replication of DNA initiated?

a. a coenzyme joins to the polymerase to allow it to begin synthesizing DNA.

b. Short sing-stranded DNA molecules called primers exist in the nucleus, and they bind to the DNA to allow synthesis to begin.

c. An enzyme called primase creates a short RNA primer that can be extended by DNA polymerase.

d. Telomerase extends the DNA strand to create a starting point.

8. During DNA replication, replacement of RNA primers and connection of the Okazaki fragments are carried out by

a. primase and telomerase, respectively.

b. ligase and telomerase, respectively

c. DNA polymerase I and ligase, respectively

d. helicase and ligase, respectively

9. In a DNA double helix, the nucleotides in a single strand are held together by ______bonds, and the two strands are held together by ______bonds.

a. hydrogen, covalent

b. hydrogen, ionic

c. ionic, hydrogen

d. covalent, hydrogen

10. How does DNA synthesis along the lagging strand differ from that on the leading strand?

a. Nucleotides are added to the 5’ end instead of the 3’ end.

b. Ligase is the enzyme that polymerizes DNA on the lagging strand.

c. An RNA primer is needed on the lagging strand but not the leading strand.

d. Okazaki fragments, which each grow 5’ to 3’, must be joined along the lagging strand.

11. Which of the following is least related to the others in the list, in terms of function?

a. primase

b. DNA polymerase

c. ligase

d. RNA polyermase

12. Which of the following statement about telomeres is correct?

a. They are ever-shortening tips of chromosomes that may signal cells to stop dividing at maturity.

b. They are highly repetitive sequences at the tips of chromosomes that protect the leading strand during replication

c. They are enzymes in germ cells that allow these cells to undergo repeated cell divisions.

d. All of the above are correct.

13. In what ways does RNA differ from DNA?

14. Fill in the following sequence in the flow of genetic information, often called the central dogma. Above each arrow, write the name of the process involved.

______

15. Determine the amino acid sequence for a polypeptide coded for by the following mRNA transcript:

AUGCCUGACUUUAAGUAG

16. Describe the key steps of transcription as they occur in eukaryotes:

a.

b.

c.

17. How does the mRNA that leaves the nucleus differ from the pre-mRNA?

18. Define the following terms and explain what type of small scale mutation could cause each of these types of mutations.

a. silent mutation

b. missense mutation

c. nonsense mutation

d. frameshift mutation

19. Transcription involves the transfer of information from

a. DNA to RNA

b. mRNA to an amino acid sequence.

c. DNA to an amino acid sequence.

d. the nucleus to the cytoplasm.

20. A gene that is 600 nucleotides long can code at most for a polypeptide of how many amino acids?

a. 200b. 600

c. 300d. 1,800

21. Which enzyme synthesizes tRNA?

a. DNA polymerase

b. RNA polymerase

c. aminoacyl – tRNAsynthetase

d. ribosomal RNA

22. Which of the following is not involved in the formation of eukaryotic transcription initiation complex?

a. TATA box in a promoter

b. transcription factors

c. small RNA molecules

d. RNA polymerase II

23. Which of the following is true of RNA processing?

a. Exons are excised before the mRNA is translated.

b. signal peptides are added to the 5; end of thr transcript.

c. Assemblies of protein and small RNAs, called spliceosomes, may catalyze splicing.

d. Large quantities of rRNAare assembled into ribosomes.

24. Prokaryotes, but not eukaryotes, are capable of

a. simultaneous transcription and translation

b. alternative splicing of introns

c. transcription using RNA polymerase

d. 5’ capping of mRNA

25. Some mutations have little effect on protein function. Since gene sequence controls protein structure, how is this possible?

a. Some mutations change a triplet coding for an amino acid into another triplet code for the same amino acid.

b. some mutations substitute a chemically similar amino acid so that the function of the protein is preserved.

c. Some substituted amino acids are in nonessential regions of the protein.

d. All of a, b, and c would minimize the effect of mutations on the protein function.

26. A ribozyme is an

a. exception to the one gene-one RNA molecule axiom.

b. enzyme that adds the 5’ cap and poly-A tail to mRNA

c. RNA molecule that functions as an enzyme.

d. enzyme that produces both small and large ribosomal subunits.

27. Changes in a polypeptide following translation may involve the

a. addition of sugars or lipids to certain amino acids.

b. enzymatic addition of amino acids at the beginning of the chain.

c. removal of poly-A from the end of the chain.

d. addition of a 5’ cap of a modified guanosine.

28. In the Avery experiments, removing nearly all of the protein from the dead S Streptococcus did not reduce the transforming activity. What properties of the transforming substance suggested that it was DNA?

29. How did Hershey and Chase conclude that the Genetic information that bacteriophages use to infect bacteria is DNA, not protein?

30. Watson and Crick deduced the structure of DNA based on what was known from Chargaff’s, and Franklin and Wilkins experiments. What did these scientists discover and how was this interpreted in the Watson-Crick model?

31. When deoxyribose molecules bind in DNA Formation, (a) what kind of reaction takes place? (b) what kind of bond is formed? (c) which carbons Are involved in the respective molecules?

32. What is the evidence for the conclusion that DNA replication is semiconservative?

33. What is the role of the RNA primer in DNA replication?

34. Why does replication on the lagging strand occur away from the replication fork instead of toward it as in the leading strand?

35. Why are the single-stranded binding protein needed in DNA replication?

36. What is the purpose of DNA topoisomerase in DNA replication?

37. DNA polymerase I, unlike the other DNA polyermases has 5’ to 2’ exonuclease activity that is essential during lagging strand replication to
a. removed damaged Okazaki fragments.
b. repair damaged template DNA.
c. degrade template DNA.
d. remove RNA primers
e. remove overlapping segments of Okazaki fragments.

38. The two strands of DNA found in a double helix are ______.
a. semidiscontinuous
b. antiparralel
c. identical
d. linked by a phosphodiester bond

39. Griffith infected mice with different strains of bacteria to demonstrate the presence of genetic material in bacteria. Which of the following best describes Griffith’s explanation for on eof his observations?

a. Dead bacteria are less lethal than live ones.
b. Genetic material transferred from dead type s bacteria into live type r bacteria transform them into bacteria capable of killing a mouse.
c. Genetic material in type s bacteria allowed them to evade the immune system.
d. Genetic material in type r bacteria transferred to dead type s bacteria restored their life and allowed them to kill mice again.
e. High levels of the heat killed type s bacteria localized to the lungs killing the mice.

40. The fact that some viruses use DNA to direct their heredity was demonstrated by finding
a. radioactive sulfur from a bacteriophage in a bacterium.
b. radioactive phosphorous from a bacterium in a bacteriophage.
c. that radioactive phosphorous from a bacteriophage had mutated a bacterium.
d. radioactive phosphorous from a bacteriophage in a bacterium.
e. radioactive sulfur from a bacterium in a bacteriophage.

41. What functional group is found at the 5’ end of a DNA strand?
a. a phosphate group
b. a hydroxyl group
c. a carbonyl group
d. a deoxyribose sugar
e. a carboxyl group

42. ______is a ______that forms ______H-bonds with ______.
a. Guanine, purine, 3, cytosine
b. Thymine, purine, 2, adenine
c. Adenine, purine, 3, thymine
d. Cytosine, pyrimidine, 2, guanine

43. Which of the following is true of standard Watson-Crick base pairing in a molecule of DNA?
a. Purines base pair with purines
b. Pyrimidines base pair with pyrimidines
c. Purines base pair with pyrimidines
d. All bases can potentially base pair
e. More than one of the above are correct.

44. Which of the following statements best describes why synthesis of the lagging strand is discontinuous?a. DNA polymerase can synthesize DNA only in the 3’ to 5’ direction.
b. DNA polymerase requires a primer to initiate synthesis.
c. DNA polymerase can synthesize DNA only in the 5’ to 3’ direction.
d. DNA polymerase is not a processive enzyme.

45. Since the first nucleotide cannot be linked in a newly synthesized srand in DNA replication, ____ is required.
a. a DNA primer
b. DNA polymerase
c. ligase
d. an RNA primer
e. helicase

Ch. 17 Terms

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  1. Central dogma
  2. Codon
  3. Start codon
  4. Stop Codon
  5. Transcription
  6. translation
  7. template strand
  8. coding strand
  9. mRNA
  10. tRNA
  11. promoter
  12. terminator
  13. transcription bubble
  14. operon
  15. transcription factors
  16. TATA box
  17. pre-mRNA
  18. 5’ cap
  19. poly A tail
  20. introns
  21. exons
  22. spliceosome
  23. snRNPs
  24. alternative splicing
  25. ribosome
  26. wobble
  27. A site
  28. P site
  29. E site
  30. point mutation
  31. nonsense mutation
  32. missense mutation
  33. frameshift mutation

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46. What are the roles of the three forms of RNA?

47. Why are the terms transcription and translation appropriate for their respective processes?

48. What is the function of the 5’ caps and the poly A tail?

49. In the initiation of transcription, what does RNA polyermase do?

50. How are introns dealt with before translation?

51. The function of tRNA is to
a. provide a place for polypeptide synthesis.
b. transport amino acids to the ribosome.
c. travel to the ribosome to direct the assembly of polypeptides.
d. transcribe DNA.
e. translate DNA.

52. Which of the following must take place in a eukaryote before a pre-mRNA transcript can be translated?
a. 5’ capping
b. poly A tail addition
c. mRNA transport to the cytoplasm
d. pre-mRNA splicing
e. all of the above

53. In eukaryotes, ___ codons specify amino acids
a. 21b. 24c. 61d. 64e. 60

54. A mutation that changes a thymine to a guanine is what type of mutation?
a. translocation mutationb. point mutation
c. inversiond. frameshift

55. In the process of translation,
a. a strand of mRNAis formed with nucleotide sequences complementary to those of DNA.
b. nucleotide sequences of tRNA are established.
c. a polypeptide is formed in response to the rRNA nucleotide sequence.
d. rRNA is synthesized with sequences complementary to those of tRNA.
e. a polypeptide is formed as dictated by the nucleotide sequences in mRNA.

56. As polypeptide are formed at the ribosome, elongation continues until ______is exposed.
a. a release factor
b. an intron
c. a stop codon
d. an exon
e. polypeptidase.

57. A spliceosome is formed from a cluster of
a. spRNAs.
b .smRNAs.
c. ribosomes.
d. nucleosomes.
e. snRNPs.

58. Replicate this strand of DNA:
ATGCAGTCGATG

TACGTCAGCTAC

59. If a DNA strand were to replicate, would they be the same or different? Why?

60. How does the structure of a DNA molecule help account for the great variety of life that exists on earth?

61. If a DNA strand read AAC GTC GCG TAC, what would the mRNA strand be?

62. Does the mRNA model more closely resemble the DNA strand from which it was transcribed or the complementary strand that wasn’t used? Explain

63. Explain how the structure of DNA enables the molecule to be easily transcribed. Why is this important for genetic information?

64. Why is RNA important to the cell? How does an mRNA molecule carry information from DNA?

65. Write the Amino Acid Sequence for the following mRNA

UUG CAG CGC AUG

66. Would you make a complete protein? Explain.

67. Transcribe and translate the following DNA sequence. Draw a line separating each codon:

A T C G T C C A A

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