Principles of Biology
Study Questions
Fall, 2006
CHAPTER 16: Molecular Basis of Inheritance
1.
Summarize the experiments performed by the following scientists that provided evidence that DNA
is the genetic material:
a. Frederick Griffith
b. Alfred Hershey and Martha Chase
c. Erwin Chargaff
2.
Explain how Watson and Crick deduced the structure of DNA and describe the evidence they used.
3.
Explain the significance of the research of Rosalind Franklin.
4.
Describe the structure of DNA.
5.
Explain the base-pairing rule and describe its significance.
5.
Describe the semiconservative model of replication.
6.
Describe the process of DNA replication, including the role of the origins of replication and
replication forks.
7.
Explain the role of DNA polymerases in replication.
9.
Define antiparallel and explain why continuous synthesis of both DNA strands is not possible.
10.
Distinguish between the leading strand and the lagging strand.
11. Explain how the lagging strand is synthesized even though DNA polymerase can add nucleotides only
to the 3’ end. Describe the significance of Okazaki fragments.
12. Explain the roles in replication of DNA ligase, primer, primase, helicase, topoisomerase, and singlestrand binding proteins.
13. Explain the significance of the DNA proofreading and repair.
14.Describe the structure and function of telomeres.
14) Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately, what
percentage of the nucleotides in this sample will be thymine?
A) 12
D) 38
B) 24
E) It cannot be determined from the
C) 31
information provided.
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15) Chargaff's analysis of the relative base composition of DNA was significant because he was able to
show that
A) the relative proportion of each of the four bases differs from species to species.
B) the human genome is more complex than that of other species.
C) the amount of A is always equivalent to T, and C to G.
D) both A and C
E) both B and C
16) All of the following can be determined directly from X-ray diffraction photographs of crystallized
DNA except the
A) diameter of the helix.
D) spacing of the nitrogenous bases along the
B) helical shape of DNA.
helix.
C) sequence of nucleotides.
E) number of strands in a helix.
17) The DNA double helix has a uniform diameter because ________, which have two rings, always pair
with ________, which have one ring.
A) purines; pyrimidines
D) ribose sugars; deoxyribose sugars
B) pyrimidines; purines
E) nucleotides; nucleoside triphosphates
C) deoxyribose sugars; ribose sugars
18) What kind of chemical bond is found between paired bases of the DNA double helix?
A) hydrogen
D) sulfhydryl
B) ionic
E) phosphate
C) covalent
19) Which of the following statements does not apply to the Watson and Crick model of DNA?
A) The two strands of the DNA form a double helix.
B) The distance between the strands of the helix is uniform.
C) The framework of the helix consists of sugar-phosphate units of the nucleotides.
D) The two strands of the helix are held together by covalent bonds.
E) The purines form hydrogen bonds with pyrimidines.
20) It became apparent to Watson and Crick after completion of their model that the DNA molecule
could carry a vast amount of hereditary information in its
A) sequence of bases.
D) side groups of nitrogenous bases.
B) phosphate-sugar backbones.
E) different five-carbon sugars.
C) complementary pairing of bases.
21) In an analysis of the nucleotide composition of DNA, which of the following is true?
A) A = C
D) G + A = T + C
B) A = G and C = T
E) both C and D
C) A + C = G + T
22) Which of the following statements is false when comparing prokaryotes with eukaryotes?
A) The prokaryotic chromosome is circular, whereas eukaryotic chromosomes are linear.
B) Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have
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many.
C) The rate of elongation during DNA replication is higher in prokaryotes than in eukaryotes.
D) Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not.
E) Eukaryotes have telomeres, and prokaryotes do not.
23) The strands that make up DNA are antiparallel. This means that
A) the twisting nature of DNA creates nonparallel strands.
B) the 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
C) base pairings create unequal spacing between the two DNA strands.
D) one strand is positively charged and the other is negatively charged.
E) one strand contains only purines and the other contains only pyrimidines.
24. Be able to label and state the function of the items in any of the figures on the lecture notes.
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