Chapter 13 Flashcards
Griffith’s studies of Streptococcus pneumoniae
A. showed that DNA is the genetic material of bacteria.
B. showed that DNA is the genetic material of bacteriophage.
C. demonstrated the phenomenon of bacterial transformation.
D. proved that prokaryotes reproduce sexually.
E. proved that protein is not the genetic material.
C
In the Hershey–Chase experiment,
A. DNA from parent bacteriophage appeared in progeny bacteriophage.
B. most of the phage DNA never entered the bacteria.
C. more than three-fourths of the phage protein appeared in progeny phage.
D. DNA was labeled with radioactive sulfur.
E. DNA formed the coat of the bacteriophage.
A
Which statement about complementary base pairing is not true?
A. Complementary base pairing plays a role in DNA replication.
B. In DNA, T pairs with A.
C. Purines pair with purines, and pyrimidines pair with pyrimidines.
D. In DNA, C pairs with G.
E. The base pairs are of equal length.
C
In semiconservative replication of DNA,
A. the original double helix remains intact and a new double helix forms.
B. the strands of the double helix separate and act as templates for new strands.
C. polymerization is catalyzed by RNA polymerase.
D. polymerization is catalyzed by a double-helical enzyme.
E. DNA is synthesized from amino acids.
B
Which of the following does not occur during DNA replication?
A. Unwinding of the parent double helix
B. Formation of short pieces that are connected by DNA ligase
C. Complementary base pairing
D. Use of a primer
E. Polymerization in the 3′-to-5′ direction
E
The primer used for DNA replication
A. is a short strand of RNA added to the 3′ end.
B. is needed only once on a leading strand.
C. remains on the DNA after replication.
D. ensures that there will be a free 5′ end to which nucleotides can be added.
E. is added to only one of the two template strands.
B
One strand of DNA has the sequence 5′-ATTCCG-3′ The complementary strand for this is
A. 5′-TAAGGC-3′
B. 5′-ATTCCG-3′
C. 5′-ACCTTA-3′
D. 5′-CGGAAT-3′
E. 5′-GCCTTA-3′
D
The role of DNA ligase in DNA replication is to
A. add more nucleotides to the growing strand one at a time.
B. open up the two DNA strands to expose template strands.
C. ligate base to sugar to phosphate in a nucleotide.
D. bond Okazaki fragments to one another.
E. remove incorrectly paired bases.
D
The polymerase chain reaction
A. is a method for sequencing DNA.
B. is used to transcribe specific genes.
C. amplifies specific DNA sequences.
D. does not require DNA replication primers.
E. uses a DNA polymerase that denatures at 55°C.
C
What is the correct order for the following events in excision repair of DNA? (1) DNA polymerase I adds correct bases by 5′ to 3′ replication; (2) damaged bases are recognized; (3) DNA ligase seals the new strand to existing DNA; (4) part of a single strand is excised.
A. 1, 2, 3, 4
B. 2, 1, 3, 4
C. 2, 4, 1, 3
D. 3, 4, 2, 1
E. 4, 2, 3, 1
C
Which of the following statements about the work of Griffith (below) and then Avery, MacLeod, and McCarty on Streptococcus pneumoniae is false?
A. Only the S strain has a cell wall-like capsule.
B. The mouse in Griffith’s experiments would not have died if injected with living S strain and heat-killed R strain.
C. The transforming principle is associated with the S strains capsule.
D. Transformation of living R strain into S strain could also occur in a test tube without involving a mouse.
E. The transforming principle carried heritable information.
B
Which of the following was not important evidence that helped advance the idea that DNA is the genetic material?
A. DNA is present in the head of the T2 bacteriophage, but protein is only in its coat.
B. The amount of DNA staining is constant in the cells of a species, except that gametes have one-half as much as somatic cells.
C. Heat-killed S strain pneumococcus could transform living R strain into virulent S strain.
D. Avery, MacLeod, and McCarty demonstrated that the transforming principle is DNA.
E. In the Hershey–Chase blender experiment, only 32P ended up in the bacteria.
A
Which of the following statements about the Hershey–Chase experiment (shown) is false?
A. Sulfur is present in protein, but not in DNA; phosphorus is present in DNA, but not in protein.
B. After infection of the bacterium with 35S-labeled T2 phage and centrifugation, the pellet would be highly radioactive.
C. The purpose of the blender is to detach viruses from the bacteria.
D. Progeny generations of T2 bacteriophage contained 32P, but no 35S.
E. A conclusion of the Hershey–Chase experiment was that T2 transfers DNA, and not protein, to the bacterium.
B
The cytosine content of DNA from a mouse cell was estimated to be 30 percent of the total pyrimidine content. Using Chargaff’s rules (shown), the percentage of total nucleotides in the DNA represented by adenine is
A. unknown; insufficient information is given to calculate the adenine content.
B. 70 percent.
C. 35 percent.
D. 30 percent.
E. 15 percent.
C
Which of the following statements about the structure of DNA shown in the accompanying figure is false?
A. The DNA double helix has a uniform diameter.
B. The DNA molecule is “right-handed.”
C. The two strands of DNA are not parallel.
D. The two strands of DNA in the double helix are held together by covalent bonds.
E. The DNA double helix exhibits “complementary base pairing.”
D
A bacterial culture was grown for many generations in the presence of 14NH4Cl (“light” nitrogen) and then switched to media that contained 15NH4Cl (“heavy” ntirogen). DNA was isolated from cells before, and one generation after, the switch, and subjected to density gradient centrifugation. Which of the following results would hold true if DNA replication were conservative?
A. Equal amounts of heavy and light DNA
B. DNA of intermediate density
C. Heavy DNA
D. Light DNA
E. A, C, and D
E
Which of the following choices does not correctly identify a labeled DNA component in the double helix shown here?
A. 1 = phosphate
B. 2 = deoxyribose sugar
C. 3 = purine base
D. 4 = hydrogen bond
E. 5 = 5′ end
E
Complete the following sentence about the figure shown here: The template strand is on the _______, and _______ will be added next to the _______ end of the growing strand.
A. right; dGTP; 3′
B. right; dGTP; 5′
C. right; dCTP; 3′
D. left; dCTP; 5′
E. left; dTTP; 3′
C
Which of the following statements regarding DNA replication origins (shown) is false?
A. DNA helicase is required to unwind the double helix at each replication origin.
B. At the end of replication, circular DNAs require DNA topoisomerase to separate the interlocking molecules produced.
C. Separated DNA strands are bound by single-stranded binding proteins to inhibit reassociation.
D. Linear chromosomes have multiple origins of replication, but only one replication fork.
E. In circular DNA molecules, the replication complex binds to the “origin” or ori.
D
Which of the following statements about DNA replication is false?
A. There are multiple DNA polymerases in eukaryotes.
B. In many organisms DNA replication requires ribonucleoside triphosphates.
C. Replication proceeds from 5′ to 3′ in the leading strand and 3′ to 5′ in the lagging strand.
D. DNA ligase is needed to complete the synthesis of the lagging strand.
E. DNA polymerase I removes the primers.
C
Below is a list of five steps that occur during the formation of a replication fork and the initiation of replication (shown here). From this list, which would be the fifth step in the process?
A. Attachment of DNA polymerase III
B. Attachment of single-stranded DNA-binding proteins
C. Unwinding of DNA by helicase
D. Synthesis of leading and lagging strands
E. Formation of RNA primer by RNA primase
D
The following figure shows two steps in the processing of Okazaki fragments in replication of the lagging strand. Choose the description that best describes what happens between these two steps.
A. DNA ligase replaces the Okazaki fragments with DNA.
B. DNA ligase catalyzes the formation of phosphodiester linkages.
C. DNA polymerase I replaces the RNA primer with DNA.
D. DNA polymerase I replaces the Okazaki fragments with DNA.
E. DNA polymerase III synthesizes Okazaki fragments.
C
Which of the following statements regarding telomeres (shown) present at the end of eukaryotic chromosomes is false?
A. Telomerase is an enzyme specialized at catalyzing the addition of lost telomeric sequences.
B. Telomerase contains an RNA sequence that acts as a template for the addition of the telomeric sequence (TTAGGG) to the ends of chromosomes.
C. Telomeres consist of a repeated sequence of nucleotides (TTAGGG in humans).
D. Telomerase is expressed in all human tissues.
E. Telomere length is correlated with the age of a cell.
D
Which of the following statements about DNA proofreading and repair (shown) is false?
A. The type of repair mechanism shown here is called mismatch repair.
B. In eukaryotes, mismatch repair replaces mismatched bases in the chemically modified strand containing methyl (—CH3) groups.
C. Excision repair corrects DNA that has become damaged by chemicals or high energy radiation.
D. Proofreading repair occurs concurrently with replication.
E. In all DNA repair mechanisms, only DNA polymerase replaces the removed bases.
B
Which of the following statements regarding the polymerase chain reaction (PCR, shown), is false?
A. Short regions of DNA are copied many times in a test tube by DNA polymerase.
B. PCR requires the separation of template DNA strands prior to synthesis.
C. PCR requires prior knowledge of the DNA sequence for the segment to be amplified.
D. Each cycle of PCR essentially doubles the number of DNA molecules in the test tube.
E. The DNA polymerase used in PCR is easily denatured by heat.
E
In PCR, ___ creates single-stranded DNA template molecules.
A. heat
B. high salt concentration
C. DNA polymerase
D. exonuclease
E. a primer
A
The first repair of mistakes during DNA replication is made by
A. the mismatch repair system.
B. DNA polymerase.
C. excision repair.
D. SOS repair.
E. postreplication repair.
B
Griffith was able to distinguish the two strains of pneumococcus by means of
A. the appearance of the colonies of the culture.
B. differences in their lethality in mice.
C. their sizes.
D. their odors.
E. Both a and b
E
In a growing DNA strand, each monomer is added to which carbon of the deoxyribose?
A. 1’
B. 2’
C. 3’
D. 4’
E. 5’
C
In the 1920s, circumstantial evidence indicated that DNA was the genetic material. Which of the following experiments led to the acceptance fo this hypothesis?
A. Griffith’s experiments with Streptococcus pneumoniae
B. Avery, MacLeod, and McCarty’s work with isolating the transforming principle
C. Hershey and Chase’s experiments with viruses and radioisotopes
D. Franklin’s X-ray crystallography
E. a, b, and c
E
