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
The PCR technique
A. can amplify only very small samples of DNA.
B. amplifies several random DNA sequences within a genome.
C. requires synthetic primers to flank the regions of interest.
D. is accomplished in three sequential steps: annealing, denaturation, and replication.
E. generates DNA molecules that all have variable sequences.
C
The characteristic of DNA that allows it to make an exact copy of itself is its
A. sugar-phosphate backbone.
B. complementary base pairing.
C. phosphodiester bonding of the belices.
D. twisting of the molecule to form an alpha helix.
E. antiparallel strands.
B
In the Hershey-Chase experiments, bacteriophage proteins were labeled by carrying out an infection of E. coli cells growing in ___ while nucleic acids were labeled by growing the bacteria in ___.
A.14C-labeled CO2; 3H-labeled water.
B. 3H-labeled water; 14C-labeled CO2.
C. 35S-labeled sulfate; 32P-labeled phosphate.
D. 32P-labeled phosphate; 35S-labeled sulfate.
E. 14C-labeled carbon; 32P-labeled phosphate.
C
During replication, the new DNA strand is synthesized
A. in the 3’-5’ direction.
B. in the 5’-3’ direction.
C. in both a and b directions from the replication fork.
D. from one end to the other, either in the a or b direction.
E. None of the above
B
The Meselson-Stahl experiment showed that DNA
A. replication is conservative.
B. is synthesized in only one direction.
C. replication is dispersive.
D. replication is semiconservative.
E. exists as a double helix.
D
The energy necessary for making a DNA molecules comes directly from
A. sugar.
B. ATP.
C. the release of phosphates.
D. NADPH.
E. NADH.
C
Double-stranded DNA looks a little likea ladder that had been twisted into a helix, or spiral. The side supports of the ladder are
A. individual nitrogenous bases.
B. alternating bases and sugars.
C. alternating bases and phosphate groups.
D. alternating sugars and phosphates.
E. alternating bases, sugars, and phosphates.
D
The rules formulated by Erwin Chargaff state that
A. A = T and G = C in any molecule of DNA.
B. A = C and G = T in any molecule of DNA.
C. A = G and C = T in any molecule of DNA.
D. A = U and G = C in any molecules of RNA.
E. DNA and RNA are made up of the same four nitrogenous bases.
A
thymine (T)
nitrogen-containing base found in DNA
pairs with adenine
DNA ligase
enzyme that unites broken DNA strands during replication and recombination
Okazaki fragments
pieces of newly-formed DNA that are complementary to lagging strand in DNA replication
transfection
insertion of recombinant DNA into animal cells
DNA helicase
enzyme that unwinds double helix in DNA
polymerase chain reaction
(abbreviation)
PCR
(long form)
polymerase chain reaction (PCR)
enzymatic technique for production of many copies of portion of DNA
usually, only small amt. of parent molecule is available
origin of replication
DNA sequence at which DNA helicase unwinds the double helix
ALSO, where DNA polymerase binds to begin DNA replication
5’ end
end of DNA/RNA strand that has a free phosphate group at one of the carbons of the sugar
DNA topoisomerase
enzyme that unwinds and winds coils of DNA that form during replication and transcription
telomere
repeated DNA sequence at end of eukaryotic chromosome
transforming principle
chemical substance responsible for bacterial transformation
base pair (bp)
pair of nucleotides formed by pairing of a purine and a pyrimidine
telomerase
enzyme that adds telomeric sequences that were lost to chromosomes during DNA replication
template
molecule/surface on which another molecule is synthesized in a complementary fashion
3’ end
end of DNA/RNA strant that has a free hydroxyl group at one of the sugar carbons
processive
describing an enzyme that catalyzes many reactions each time it is bound to its substrate
e.g. DNA polymerase during DNA replication
replication fork
point at which DNA molecule is replicating; formed by unwinding of parent molecule
genetic marker
DNA sequence whose presence is correlated with presence of other linked genes on a chromosome
or, gene with known phenotype that indicates presence of another gene, DNA segment, or chromosome fragment
excision repair
removal of damaged DNA, and subsequent replacing with appropirate nucleotide
semiconservative replication
method in which DNA is synthesized
two strands in DNA act as a template for a new partner strand; each new helix consists of an old strand and a new strand
sliding DNA clamp
protein complex that keeps DNA polymerase bound to DNA during DNA replication
cytosine (C)
nitrogen-containing base found in DNA & RNA
pairs with guanine
single-strand binding protein
protein that binds to single strands of DNA after they have separated to keep them separate for the replication process
replication process
association of several proteins operating in replication of DNA
DNA polymerase
enzymes that catalyze formation of DNA strands from a DNA template
guanine (G)
nitrogen-containing base found in DNA & RNA & GTP
pairs with cytosine
proofreading
correction of error in DNA replication just after an incorrectly paired base is added to the growing polynucleotide chain
mismatch repair
mechanism that scans DNA after it has replicated to correct any incorrect base-pairings
adenine (A)
nitrogen-containing base found in nucleic acids, ATP, and NAD
pairs with thymine
antiparallel
molecular orientation in which molecule or parts of molecule are oriented in opposite directions
e.g. 3’-5’ and 5’-3’
lagging strand
daughter strands that is synthesized in discontinuous streches in DNA replication
primer
strand of nucleic acid (usually RNA) that is the starting material for synthesis of new DNA strand
leading strand
daughter strand that is continuously synthesized
proliferating cell nuclear antigen
(abbreviation)
PCNA
(long form)
proliferating cell nuclear antigen (PCNA)
protein complex that ensures processivity of DNA replication in eukaryotes
primase
enzyme that catalyzes the synthesis of a primer for DNA replication
complementary base pairing
specific pairing of bases in double stranded DNA, transcription, and between tRNA and mRNA
