Deck 13: Dna and Its Role in Heredity

Question 1

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.

Answer 1

A

Question 2

The Hershey-Chase experiment persuaded most scientists that

A) bacteria can be transformed.
B) DNA is indeed the carrier of hereditary information.
C) DNA replication is semiconservative.
D) the transforming principle requires host factors.
E) All of the above

Answer 2

B

Question 3

In the 1920s, circumstantial evidence indicated that DNA was the genetic material. Which of the following experiments led to the acceptance of 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

Answer 3

E

Question 4

In Griffith's experiments, when heat-killed S strain pneumococci were injected into a mouse along with live R strain pneumococci,

A) DNA from the live R was taken up by the heat-killed S, converting the latter to R and killing the mouse.
B) DNA from the heat-killed S was taken up by the live R, converting the latter to S and killing the mouse.
C) proteins released from the heat-killed S killed the mouse.
D) RNA from the heat-killed S was translated into proteins that killed the mouse.
E) there was no result.

Question 5

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.

Question 6

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.

Question 7

In the 1920s a dye was developed that bound to DNA and stained nuclei in direct proportion to the amount of DNA present in cells. The resulting experiments

A) provided circumstantial evidence that DNA is the genetic material.
B) proved DNA is the genetic material.
C) demonstrated that all species had the same amount of nuclear DNA.
D) demonstrated that diploid and haploid cells could not have differing amounts of DNA.
E) confirmed that DNA was an important component of mitochondria and chloroplasts.

Question 8

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.

Question 9

Griffith was able to distinguish the two strains of pneumococcus by means of

A) the appearance of the colonies in culture.
B) differences in their lethality in mice.
C) their sizes.
D) their odors.
E) Both a and b

Question 10

To show that DNA is the "transforming principle," Avery, MacLeod, and McCarty showed that DNA could transform nonvirulent strains of pneumococcus. Their hypothesis was strengthened by their demonstration that

A) enzymes that destroy proteins also destroy transforming activity.
B) enzymes that destroy nucleic acids also destroy transforming activity.
C) enzymes that destroy complex carbohydrates also destroy transforming activity.
D) the transforming activity is destroyed by boiling.
E) other strains of bacteria also can be transformed successfully.

Question 11

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

Question 12

Before the discovery of DNA, the hereditary material was thought to be made of proteins and not nucleic acids because

A) nucleic acids are made up of 20 different bases, whereas proteins are made up of only five amino acids.
B) protein subunits can combine to form larger proteins.
C) proteins seemed to be much more chemically diverse.
D) proteins can be enzymes.
E) None of the above

Question 13

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

Question 14

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´

Question 15

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.

Question 16

The Hershey-Chase experiment

A) proved that DNA replication is semiconservative.
B) used ³²P to label protein.
C) used ³⁵S to label DNA.
D) helped prove that DNA is the genetic molecule.
E) Both b and c

Question 17

Experiments designed to identify the "transforming principle" were based on

A) purifying each of the macromolecule types from a cell-free extract.
B) removing each of the macromolecules from a cell, then testing its type.
C) selectively destroying the different macromolecules in a cell-free extract.
D) Both a and b
E) Both a and c

Question 18

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.

Question 19

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.

Question 20

Griffith's experiment with pneumococcus demonstrated that

A) smooth bacteria can survive heating.
B) DNA, not protein, is the genetic molecule.
C) materials from dead organisms can affect and change living organisms.
D) nonliving viruses can change living cells.
E) None of the above

Question 21

The nitrogenous bases (and the two strands of the DNA double helix) are held together by

A) weak van der Waals forces.
B) covalent bonds.
C) hydrogen bonds.
D) Both a and b
E) Both a and c

Question 22

Which of the following molecules functions to transfer information from one generation to the next in eukaryotes?

A) DNA
B) mRNA
C) tRNA
D) Proteins
E) Lipids

Question 23

Which of the following molecular models describes the structure of the DNA molecule?

A) Single-stranded
B) Antiparallel
C) Triple-stranded
D) Helical
E) Helical, double-stranded, and antiparallel

Question 24

The DNA isolated from a newly discovered virus is found to be 32 percent A, 18 percent C, 18 percent G, and 32 percent T. The base composition of the complementary DNA would be _______ percent A, _______ percent C, _______ percent G, and _______ percent T.

A) 32; 17; 32; 19
B) 19; 32; 17; 32
C) 17; 32; 32; 19
D) 25; 25; 25; 25
E) 32; 18; 18; 32

Question 25

An alien DNA-like molecule is isolated from the frozen remains of a life-form found beneath the Martian polar ice caps. In this sample, for every base designated Q, there is twice that amount of base R; for every base Z, there is twice that amount of base S. If the molecule contains 33.33 percent R, what percentage of Z would you expect?

A) 6
B) 12
C) 24
D) 16.67
E) 54.66

Question 26

The structure of DNA is characterized by a

A) right- or left-handed double helix and antiparallel strands.
B) right-handed double helix and antiparallel strands.
C) right-handed single helix.
D) right-handed single helix and parallel strands.
E) All of the above

Question 27

Information sources used by Watson and Crick to determine the structure of DNA included

A) electron micrographs of individual DNA molecules.
B) light micrographs of bacteriophage particles.
C) light micrographs of individual bacterial chromosomes.
D) nuclear magnetic resonance analysis of DNA.
E) X-ray crystallography of double-stranded DNA.

Question 28

The structure of the DNA molecule was determined by the experiments of

A) Wilkins.
B) Franklin.
C) Watson.
D) Crick.
E) All of the above

Question 29

During infection of E. coli cells by bacteriophage T2,

A) proteins are the only phage components that enter the infected cell.
B) both proteins and nucleic acids enter the cell.
C) only protein from the infecting phage can also be detected in progeny phage.
D) only nucleic acids enter the cell.
E) more than one infecting phage particle is required to produce infection.

Question 30

Which of the following statements about the molecular architecture of DNA is true?

A) The two strands run in opposite directions.
B) The molecule's twist is right-handed.
C) The molecule is a double-stranded helix.
D) It has a uniform diameter.
E) All of the above

Question 31

In one Hershey-Chase experiment, bacteriophage nucleic acids were labeled by carrying out an infection of E. coli cells growing in

A) ¹⁴C-labeled CO₂.
B) ³H-labeled water.
C) ³²P-labeled phosphate.
D) ³⁵S-labeled sulfate.
E) ¹⁸O-labeled water.

Question 32

Double-stranded DNA looks a little like a ladder that has 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.

Question 33

If Hershey and Chase had found ³⁵S in both the pellet and the supernatant, what would have been their likely conclusion about the nature of DNA replication?

A) A protein must be the information molecule.
B) No conclusion would have been possible from these results.
C) DNA is the genetic information molecule.
D) Phage must have stuck to the bacteria.
E) Phosphorus was in the information molecule.

Question 34

A deoxyribose nucleotide is a

A) deoxyribose plus a nitrogenous base.
B) sugar and a phosphate.
C) deoxyribose plus a nitrogenous base and a phosphate.
D) ribose plus a nitrogenous base.
E) nitrogenous base bonded at the 5' end to a sugar-phosphate backbone.

Question 35

The rungs of the DNA ladder are

A) individual nitrogenous bases.
B) pairs of bases.
C) alternating bases and phosphate groups.
D) alternating sugars and bases.
E) alternating bases, sugars, and phosphates.

Question 36

The Hershey-Chase experiment determined that

A) protein and DNA are the hereditary materials of viruses.
B) protein, not DNA, is the hereditary material of viruses.
C) viruses do not contain hereditary material.
D) DNA, not protein, is the hereditary material of viruses.
E) None of the above

Question 37

Chargaff's rule states that

A) DNA must be replicated before a cell can divide.
B) viruses enter cells without their protein coat.
C) only protein from the infecting phage can also be detected in progeny phage.
D) only nucleic acids enter the cell during infection.
E) the amount of cytosine equals the amount of guanine.

Question 38

If a double-stranded DNA molecule contains 30 percent T, it must contain _______ percent G.

A) 20
B) 30
C) 40
D) 50
E) 60

Question 39

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 molecule of RNA.
E) DNA and RNA are made up of the same four nitrogenous bases.

Question 40

Purines include

A) cytosine, uracil, and thymine.
B) adenine and cytosine.
C) adenine and thymine.
D) cytosine and thymine.
E) adenine and guanine.

Question 41

A deoxyribonucleoside is a

A) deoxyribose plus a nitrogenous base.
B) sugar and a phosphate.
C) deoxyribose plus a nitrogenous base and a phosphate.
D) ribose plus a nitrogenous base.
E) nitrogenous base bonded at the 5´ end to a sugar-phosphate backbone.

Question 42

Which feature of the Watson-Crick model of DNA structure explains its ability to function in replication and gene expression?

A) Each strand contains all the information present in the double helix.
B) There are structural and functional similarities between DNA and RNA.
C) The double helix is right-handed, not left-handed.
D) DNA replication does not require enzyme catalysts.
E) Bases are exposed in the major groove of the double helix.

Question 43

During DNA replication

A) one template strand must be degraded to allow the other strand to be copied.
B) the template strands must separate so that both can be copied.
C) the template strands come back together after the passage of the replication fork.
D) origins of replication always give rise to single replication forks.
E) two replication forks diverge from each origin but one always lags behind the other.

Question 44

Semiconservative replication of DNA involves

A) each of the original strands acting as a template for a new strand.
B) only one of the original strands acting as a template for a new strand.
C) the complete separation of the original strands, the synthesis of new strands, and the reassembly of double-stranded molecules.
D) the use of the intact double-stranded molecule as a template.
E) None of the above

Question 45

The antiparallel relationship of the two strands of DNA refers to the

A) twisted configuration of the strands.
B) alternative branching pattern of the strands.
C) alignment of the strands, such that one strand starts with a 3´ carbon and the other starts with a 5´ carbon.
D) view at one end of the molecule-one strand has an A wherever the other has a T, and one has a G wherever the other has a C.
E) All of the above

Question 46

Mutations are

A) heritable changes in the sequence of DNA bases that produce an observable phenotype.
B) heritable changes in the sequence of DNA bases.
C) mistakes in the incorporation of amino acids into proteins.
D) heritable changes in the mRNA of an organism.
E) None of the above

Question 47

Which of the following is not found in DNA?

A) Carbon
B) Oxygen
C) Nitrogen
D) Hydrogen
E) Sulfur

Question 48

What accounts for the uniform diameter of the DNA molecule?

A) The two sides of the DNA molecule are held together by hydrogen bonds.
B) A purine always bonds with a pyrimidine.
C) One side of the DNA molecule has an unconnected 5´ phosphate group, and the opposite end has an unconnected 3´ hydroxyl group.
D) The 3´ carbon of one deoxyribose and the 5´ carbon of another deoxyribose bond together.
E) The alternating sugar and phosphate backbone coils around the outside of the helix.

Question 49

The force of _______ holds DNA together in a double helix.

A) the twist
B) covalent bonds
C) ionic bonds
D) ionic interactions
E) hydrogen bonds

Question 50

At the end of DNA replication, two DNA molecules are produced, each one consisting of a parental DNA strand and a new DNA strand. This process is known as

A) semiconservative replication.
B) conservative replication.
C) dispersive replication.
D) fission.
E) the transforming principle.

Question 51

Pyrophosphate is a

A) building block for DNA synthesis.
B) by-product of DNA synthesis.
C) precursor to DNA synthesis.
D) fire phosphate used in nucleic acid metabolism.
E) All of the above

Question 52

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 helices.
D) twisting of the molecule to form an $\alpha$ helix.
E) antiparallel strands.

Question 53

The energy necessary for making a DNA molecule comes directly from

A) sugar.
B) ATP.
C) the release of phosphates.
D) NADPH.
E) NADH.

Question 54

In the Meselson-Stahl experiment, the conservative model of DNA replication was ruled out by which of the following observations?

A) No completely "heavy" DNA was observed after the first round of replication.
B) No completely "light" DNA ever appeared, even after several replications.
C) The product that accumulated after two rounds of replication was completely "heavy."
D) Completely "heavy" DNA was observed throughout the experiment.
E) Three different DNA densities were observed after a single round of replication.

Question 55

If Meselson and Stahl had observed one intermediate, slightly smeared band after growing bacteria for one generation, and then after two generations again had found one slightly smeared band, they would most likely have concluded that DNA replicates

A) semiconservatively.
B) conservatively.
C) semidiscontinuously.
D) dispersively.
E) semicontinuously.

Question 56

The structure of DNA explains which three major properties of genes?

A) They contain information, direct the synthesis of proteins, and are contained in the cell nucleus.
B) They contain nitrogenous bases, direct the synthesis of RNA, and are contained in the cell nucleus.
C) They replicate exactly, are contained in the cell nucleus, and direct the synthesis of cellular proteins.
D) They encode the organism's phenotype, are passed on from one generation to the next, and contain nitrogenous bases.
E) They contain information, replicate exactly, and can change to produce a mutation.

Question 57

Although DNA is made up of only four different bases, it can encode the information necessary to specify the workings of an entire organism because DNA

A) molecules are extremely long.
B) molecules are found in the nucleus.
C) is transcribed into RNA and then into proteins with specific functions.
D) is eventually translated into proteins, which are made up of 20 different amino acids.
E) None of the above

Question 58

The strands that make up DNA are antiparallel. This means that

A) one strand is positively charged, and the other is negatively charged.
B) the base pairings create unequal spacing between the two DNA strands.
C) the 5´-to-3´ direction of one strand is counter to the 5´-to-3´ direction of the other strand.
D) the twisting of the DNA molecule has shifted the two strands.
E) purines bond with purines and pyrimidines bond with pyrimidines.

Question 59

Kornberg showed that new DNA molecules can be synthesized in a test tube containing deoxyribose

A) nucleoside monophosphates.
B) nucleoside diphosphates.
C) nucleoside triphosphates.
D) nucleotide diphosphates.
E) nucleotide triphosphates.

Question 60

The first scientist(s) to suggest a mode of replication for DNA was (were)

A) Linus and Pauling.
B) Hershey and Chase.
C) Rosalind Franklin.
D) Watson and Crick.
E) Meselson and Stahl.

Question 61

Which of the following is not a function of the proliferating cell nuclear antigen (PCNA)?

A) Orients polymerase to bind to substrates
B) Has binding sites for DNA ligase
C) Ensures that replication only occurs once per cell cycle
D) Binds with enzymes for DNA repairs
E) Prevents DNA polymerase from bonding to DNA

Question 62

During replication, the new DNA strand is synthesized

A) in the 3´-to-5´ direction.
B) in the 5´-to-3´ direction.
C) in both the 3´-to-5´ and 5´-to-3´ directions from the replication fork.
D) from one end to the other, in the 3´-to-5´ or the 5´-to-3´ direction.
E) None of the above

Question 63

In DNA replication, each newly made strand is

A) identical in DNA sequence to the strand from which it was copied.
B) complementary in sequence to the strand from which it was copied.
C) oriented in the same 3´-to-5´ direction as the strand from which it was copied.
D) an incomplete copy of one of the parental strands.
E) a hybrid molecule consisting of both ribo- and deoxyribonucleotides.

Question 64

Fragments like those now called Okazaki fragments might have been hypothesized even before they were discovered by Reiji Okazaki because

A) DNA replicates in the 3´-to-5´ direction.
B) single-stranded DNA was appearing behind DNA polymerase.
C) DNA nucleotides were being added to the 5´ end of the primer on the lagging strand.
D) RNA primase places short RNA primer sequences along the DNA molecule.
E) DNA polymerase I can connect short segments.

Question 65

DNA polymerase lengthens a polynucleotide strand by

A) building short DNA fragments and linking them together.
B) adding lost DNA sequences to the 3´ end.
C) linking purines with pyrimidines.
D) covalently linking new nucleotides to a previously existing strand.
E) threading the existing DNA through a replication complex.

Question 66

The enzyme that unwinds the DNA prior to replication is called

A) DNA polymerase III.
B) DNA ligase.
C) single-stranded DNA binding protein.
D) primase.
E) helicase.

Question 67

The enzyme that restores the phosphodiester linkage between adjacent fragments in the lagging strand during DNA replication is

A) DNA ligase.
B) primase.
C) reverse transcriptase.
D) helicase.
E) DNA polymerase I.

Question 68

Why is a sliding DNA clamp important in DNA replication?

A) It increases the number of nucleotides polymerized.
B) It holds open the two sides of the DNA molecule.
C) It slides forward separating additional strands of the DNA molecule.
D) It temporarily holds the nucleotides together until phosphodiester bonds can form.
E) It unwinds the double helix.

Question 69

In eukaryotic cells, each chromosome has

A) one origin of replication.
B) two origins of replication.
C) many origins of replication.
D) only one origin of replication per nucleus.
E) None of the above

Question 70

Fifteen human DNA polymerases have been identified. Which of the following statements about them is true?

A) They all are involved in DNA replication.
B) One of the DNA polymerases opens the replication fork, one forms the primer, another removes the primer, and the rest are involved in protein synthesis.
C) The functions of DNA polymerase, helicase, and primase are known; the functions of the others are unknown.
D) Each DNA polymerase requires a specific primer to function.
E) Most replications are catalyzed by delta and epsilon DNA polymerases; the others are involved in primer removal and DNA repair.

Question 71

DNA replication in eukaryotes differs from replication in bacteria because

A) synthesis of the new DNA strand is from 3´ to 5´ in eukaryotes and from 5´ to 3´ in bacteria.
B) synthesis of the new DNA strand is from 5´ to 3´ in eukaryotes and from 3´ to 5´ in bacteria.
C) there are many replication forks in each eukaryotic chromosome and only one in bacterial DNA.
D) synthesis of the new DNA strand is from 5´ to 3´ in eukaryotes and is random in prokaryotes.
E) Okazaki fragments are produced in eukaryotic DNA replication but not in prokaryotic DNA replication.

Question 72

Why don't cells last the entire lifetime of an organism?

A) The removal of the RNA primer following DNA replication leads to a shortening of the chromosome and eventual cell death.
B) The enzyme telomerase is readily destroyed by the environment, resulting in cell death.
C) DNA replication is subject to errors, causing premature cell death.
D) Okazaki fragments disrupt protein synthesis, resulting in premature cell death.
E) The repeating telomeric sequence of TTAGGG interferes with normal DNA replication and leads to cell death.

Question 73

The molecules that function to replicate DNA in the cell are

A) DNA nucleoside triphosphates.
B) DNA polymerases.
C) nucleoside polymerases.
D) DNAses.
E) ribonucleases.

Question 74

Which of the following is the correct order of events for synthesis of the lagging strand?

A) Primase adds RNA primer, DNA polymerase III creates a stretch, DNA polymerase I removes the primer, and ligase seals the gaps.
B) Primase adds primer, DNA polymerase I removes the primer, DNA polymerase III extends the segment, and ligase seals the gap.
C) Ligase adds bases to the primase, the primase generates polymerase I, polymerase III adds to the stretch, helicase winds the DNA.
D) Helicase unwinds the DNA, primase creates a primer, DNA polymerase I elongates the stretch, DNA polymerase III removes the primer, and ligase seals the gaps in the DNA.
E) None of the above

Question 75

In eukaryotes, Okazaki fragments are about _______ base pairs long.

A) 50
B) 100-200
C) 1,500
D) 150,000
E) 15,000,000

Question 76

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´

Question 77

In the cells of prokaryotes, methylated adenine contributes to

A) an increased rate of DNA replication.
B) a slowed rate of DNA replication.
C) the correct separation of DNA strands.
D) proofreading of replicated strands.
E) correcting of mismatched pairs of bases.

Question 78

In bacteria, the enzyme that removes the RNA primers is called

A) DNA ligase.
B) primase.
C) reverse transcriptase.
D) helicase.
E) DNA polymerase I.

Question 79

Why is RNA incorporated into the DNA molecule during DNA replication?

A) RNA primase adds bases that act as primers.
B) RNA primase is able to use DNA as a template.
C) RNA primase must be incorporated into the holoenzyme complex.
D) DNA polymerases can only add on to an existing strand.
E) All of the above

Question 80

The enzyme DNA ligase is required continuously during DNA replication because

A) fragments of the leading strand must be joined together.
B) fragments of the lagging strand must be joined together.
C) the parental strands must be joined back together.
D) 3'-deoxynucleoside triphosphates must be converted to 5'-deoxynucleoside triphosphates.
E) the complex of proteins that work together at the replication fork must be kept from falling apart.