Deck 12: DNA: The Carrier of Genetic Information

Question 1

Which of the following nucleotide sequences represents the complement to the DNA strand, 5′-AGATCCG-3′?

A) 5′-AGATCCG-3′
B) 3′-AGATCCG-5′
C) 5′-CTCGAAT-3′
D) 3′-CTCGAAT-5′
E) 3′-TCTAGGC-5′

Answer 1

E

Question 2

X-ray diffraction studies are used to determine the

A) sequence of amino acids in protein molecules.
B) sequence of nucleotides in nucleic acid molecules.
C) distances between atoms of molecules.
D) identity of an unknown chemical.
E) wavelength of X-rays.

Answer 2

C

Question 3

According to Chargaff's rules,

A) the number of A-T base pairs is always equal to the number of G-C base pairs in all DNA molecules.
B) the adenine content in any DNA molecule is always equal to the thymine content.
C) the adenine content in any DNA molecule is always greater than the thymine content.
D) the guanine content in any DNA molecule is always less than the cytosine content.
E) there is no relationship between the ratio of purine and pyrimidine content in any DNA molecule.

Answer 3

B

Question 4

From the DNA X-ray crystallography data, Franklin and Wilkins inferred that ____, while Watson and Crick determined that ____.

A) purines and pyrimidines exist in a 1:1 ratio; DNA is helical
B) phosphates are stacked liked rungs on a ladder; DNA is helical
C) DNA is helical; DNA is the genetic material
D) DNA is helical; the flat nucleotide bases are stacked upon each other
E) the flat nucleotide bases are stacked upon each other; DNA is helical.

Question 5

How many different kinds of amino acids are known?

A) Less than 5
B) More than 5 but not more than 8
C) More than 8 but not more than 15
D) More than 70
E) More than 20

Question 6

Which of the following statements concerning DNA is FALSE?

A) The structure of DNA can be described as a double helix.
B) DNA is a polymer of nucleotides.
C) Purines and pyrimidines are complementary.
D) The sugar present in DNA is ribose.
E) The two chains of DNA are antiparallel.

Question 7

Alfred Hershey's and Martha Chase's experiments with bacteriophages showed that

A) DNA was injected into bacteria.
B) DNA and protein were injected into bacteria.
C) DNA remained on the outer coat of bacteria.
D) proteins were injected into bacteria.
E) proteins were responsible for the production of new viruses within the bacteria.

Question 8

_____ bonds link the sugar and phosphate groups in the backbone of DNA molecules.

A) Covalent phosphodiester
B) Hydrogen
C) Weak
D) Ionic
E) Weak covalent

Question 9

In the experiments of Griffith, the conversion of nonlethal R-strain bacteria to lethal S-strain bacteria

A) was due to genetic mutation.
B) was due to transformation.
C) proved that proteins are the genetic material.
D) could not be reproduced by other researchers.
E) was similar to experiments performed by Watson and Crick.

Question 10

To fit X-ray crystallographic data, the two DNA strands in Watson and Crick's model must be ____ to each other.

A) conservative
B) uncomplementary
C) parallel
D) antiparallel
E) semiconservative

Question 11

Viruses that infect bacteria are known as?

A) Bacteriophages
B) Agrobacterium
C) Mycobacterium
D) Parainfluenza virus
E) Monobacterium

Question 12

X-ray diffraction images produced by ____ were used by Watson and Crick to infer the structure of DNA.

A) Wilkins
B) Griffith
C) Franklin
D) Hershey
E) Watson and Wilkins

Question 13

The first scientists to use Griffith's transformation assay to identify genetic material were

A) Meselson and Stahl.
B) Watson and Crick.
C) Franklin and Wilkins.
D) Avery, MacLeod, and McCarty.
E) Hershey and Chase.

Question 14

Why is DNA able to store large amounts of information?

A) It is composed of 20 different nucleotides.
B) Its nucleotides can be arranged in many possible sequences.
C) It is capable of assuming a wide variety of shapes.
D) Its sugars and phosphates can be arranged in many different sequences.
E) Its bases can be altered from purines to pyrimidines.

Question 15

Hydrogen bonds can form between guanine and ____, and between adenine and ____.

A) phosphate; sugar
B) thymine; cytosine
C) cytosine; thymine
D) sugar; phosphate
E) adenine; guanine

Question 16

The information encoded by the DNA is specified by the

A) sugar-phosphate backbone of the DNA molecule.
B) number of separate DNA strands.
C) size of a particular chromosome.
D) nucleotide sequence of the DNA molecule.
E) number of bases in a DNA molecule.

Question 17

Which is a powerful method for determining the 3D structure of a molecule?

A) NMR spectroscopy
B) 3D electron microscopy
C) Infrared spectroscopy
D) Ultraviolet spectroscopy
E) X-ray diffraction

Question 18

A nucleotide is made up of a phosphate group, a five-carbon sugar molecule, and

A) two of five nitrogeneous bases.
B) one of five nitrogeneous bases.
C) one of four nitrogeneous bases.
D) two of four nitrogeneous bases.
E) three of six nitrogeneous bases.

Question 19

What are the small circular DNA molecules that carry genes separate from those on a bacterial chromosome?

A) Plasmids
B) Telomerase
C) Helicase
D) DNA ligase
E) Apoptosis

Question 20

The two molecules that alternate to form the backbone of a polynucleotide chain are

A) adenine and thymine.
B) cytosine and guanine.
C) sugar and phosphate.
D) base and sugar.
E) base and phosphate.

Question 21

Enzymes called ____ form breaks in the DNA molecules to prevent the formation of knots in the DNA helix during replication.

A) topoisomerases
B) single-strand binding proteins
C) DNA polymerases
D) RNA polymerases
E) DNA ligases

Question 22

Which of the following statements is FALSE with regard to DNA replication?

A) DNA synthesis proceeds in the 5¢->3¢ direction.
B) The strand being copied is read in the 5¢->3¢ direction.
C) Both strands are replicated at the same time.
D) The position of the replication fork is constantly moving.
E) Two identical DNA polymerase molecules catalyze replication.

Question 23

What allows each strand of DNA to serve as a template for a new DNA strand during replication?

A) Covalent bonding between nucleotide bases
B) Hydrogen bonds between the deoxyribose and the phosphate groups
C) Complementary base pairing between purines and purines on opposite strands
D) Complementary base pairing between pyrimidines and pyrimidines on opposite strands
E) Complementary base pairing between purines and pyrimidines on opposite strands

Question 24

Unlike normal cells, cancerous cells

A) have reduced levels of telomerase.
B) divide only a few times before succumbing to apoptosis.
C) have unusually short telomeres.
D) can maintain telomere length as they divide.
E) lack telomeres.

Question 25

Errors in DNA replication can come from

A) DNA polymerase.
B) DNA ligase.
C) complementary base pairing.
D) the sun's UV radiation.
E) Okazaki fragments.

Question 26

Because a newly synthesized DNA molecule contains ____, the replication process is said to be semiconservative.

A) two new strands
B) one parental strand and one new strand
C) two parental strands
D) half purines and half pyrimidines
E) nucleotides

Question 27

The ends of eukaryotic chromosomes can be lengthened by

A) apoptosis.
B) mismatch repair enzymes.
C) primase.
D) telomerase.
E) DNA polymerase.

Question 28

Which of the following consists of short, noncoding, guanine-rich DNA sequences that repeat many times?

A) DNA ligase
B) Helicase
C) Telomere
D) Plasmid
E) Apoptosis

Question 29

What are special enzymes that recognize and remove the incorrectly paired nucleotides in DNA?

A) Mismatch repair
B) Telomerase
C) Nucleotide excision repair
D) Apoptosis
E) Plasmids

Question 30

If DNA replication rejoined the two parental strands, it would be described as

A) dispersive.
B) gradient.
C) semiconservative.
D) parental.
E) conservative.

Question 31

When a mutation occurs during DNA replication, ____ replaces the incorrect nucleotide with the correct one after the mismatched nucleotide has been removed.

A) mismatch repair enzymes
B) DNA ligase
C) DNA polymerase
D) telomerase
E) helicase

Question 32

Individuals with mutations in excision repair enzymes may suffer from ____ due to unrepaired DNA damage caused by ____.

A) skin cancer; mutations inherited from their parents
B) colon cancer; the passing of DNA mutations to daughter cells
C) prostate cancer; telomerase
D) skin cancer; the sun's UV rays
E) skin cancer; complementary base pairing

Question 33

Why does DNA synthesis proceed in a 5′ to 3′ direction?

A) DNA polymerases can only add nucleotides to the 3′ end of a polynucleotide strand.
B) The 3′ end of the polynucleotide molecule contains more phosphates than the 5′ end.
C) DNA unzips in the 5¢ to 3¢ direction.
D) DNA strands are parallel to each other.
E) Chromosomes are aligned in the 5′ to 3′ direction in the nucleus.

Question 34

DNA synthesis

A) is unidirectional.
B) is facilitated by a phosphodiester linkage.
C) occurs only once during each cell generation.
D) has few mechanisms for fixing errors.
E) is proofread by DNA ligase.

Question 35

Primase is the enzyme responsible for

A) unwinding the DNA double strand to allow DNA polymerase access to the template DNA.
B) introducing nicks into the DNA double strand in order to prevent the formation of knots.
C) hydrolyzing ATP to facilitate DNA unwinding.
D) making short strands of RNA at the site of replication initiation.
E) forming a replication fork in the DNA double helix.

Question 36

The DNA strand that is replicated smoothly and continuously is called the

A) primary strand.
B) template strand.
C) leading strand.
D) Okazaki fragment.
E) lagging strand.

Question 37

Which of the following causes the unwinding of the DNA double helix?

A) DNA polymerase
B) DNA helicase
C) RNA primer
D) Primosome
E) RNA polymerase

Question 38

In replication, once the DNA strands have been separated, reformation of the double helix is prevented by

A) DNA helicase enzyme.
B) single-strand binding proteins.
C) DNA polymerases.
D) ATP.
E) DNA primase.

Question 39

Who first confirmed that the replication of DNA was semiconservative?

A) Chargaff and Hershey
B) Watson and Crick
C) Avery and Griffith
D) Meselson and Stahl
E) Watson, Crick, and Wilkins

Question 40

____, the ends of eukaryotic chromosomes, shorten with every cell division.

A) Centromeres
B) Telomeres
C) Kinetochores
D) Primosomes
E) Nucleosomes

Question 41

What happened in an experiment where normal cultured human cells were infected with a virus that carried DNA encoding for the telomerase catalytic subunit?

A) The cells underwent more cell divisions than normal.
B) The cells underwent fewer cell divisions than normal.
C) The cells died almost immediately.
D) The cells did not express the foreign telomerase gene.
E) The cell cycle shortened.

Question 42

Compare DNA synthesis in prokaryotes and eukaryotes.

Question 43

DNA Pol III catalyzes the addition of successive nucleotides to the 5' end of a growing polynucleotide chain.
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Question 44

What happens during nucleotide excision repair?

A) A mismatch mutation is repaired.
B) A nuclease removes the damaged DNA.
C) DNA polymerase joins the repaired DNA together.
D) DNA ligase adds new nucleotides to the repaired DNA strand.
E) DNA is damaged.

Question 45

One of the pyrimidine bases in a DNA molecule is adenine.

Question 46

In one strand of a DNA molecule, adjacent nucleotides are joined by a phosphodiester linkage.

Question 47

Adenine and thymine are held together by two hydrogen bonds in a double stranded DNA molecule.

Question 48

List the steps and components involved in the process of nucleotide excision repair.

Question 49

How are eukaryotic chromosomes replicated?

A) The linear DNA molecules are replicated from multiple origins of replication bidirectionally.
B) The linear DNA molecules are replicated from one origin of replication bidirectionally.
C) The circular DNA molecules are replicated from multiple origins of replication bidirectionally.
D) The circular DNA molecules are replicated from one origin of replication bidirectionally.
E) The linear DNA molecules are replicated from one origin of replication unidirectionally.

Question 50

If you consider a DNA molecule to resemble a twisted ladder, the rungs of the ladder are paired nitrogen bases.

Question 51

An RNA primer is synthesized by RNA primase.

Question 52

Okazaki fragments are joined together by

A) RNA polymerase.
B) DNA ligase.
C) DNA polymerase.
D) RNA ligase.
E) primase.

Question 53

Briefly explain why apoptosis protects the body against cancerous cells. Include why cell age is a factor in cells becoming cancerous.

Question 54

How is a bacterial chromosome replicated?

A) The linear DNA molecule is replicated from multiple origins of replication bidirectionally.
B) The linear DNA molecule is replicated from one origin of replication bidirectionally.
C) The circular DNA molecule is replicated from multiple origins of replication bidirectionally.
D) The circular DNA molecule is replicated from one origin of replication bidirectionally.
E) The circular DNA molecule is replicated from one origin of replication unidirectionally.

Question 55

In DNA replication, the lagging strand

A) is synthesized as a series of Okazaki fragments.
B) is synthesized as a complementary copy of the leading strand.
C) pairs with the leading strand by complementary base pairing.
D) is made up entirely of RNA primers.
E) is not synthesized until the synthesis of the leading strand is completed.

Question 56

Replication typically occurs at a single origin of replication in eukaryotic chromosomes.

Question 57

Single-strand binding proteins prevent the hydrolysis of single-strand regions of DNA by nucleases.

Question 58

The process of DNA replication is conservative.

Question 59

The two strands of a DNA double helix can be described as running parallel to each other.

Question 60

Explain why proteins were initially hypothesized to be the genetic material instead of DNA.

Question 63

Explain what is meant by the "directionality" of DNA strands. Also, briefly discuss how this directionality is ultimately responsible for Okazaki fragments.

Question 69

Briefly explain the experiments of Avery and his colleagues and those of Hershey and Chase. What did those experiments support?

Question 71

Briefly discuss why the degradation of telomeres result in cellular aging. Conversely, propose why telomere lengthening could result in cells becoming cancerous.

Question 78

In mismatch repair, enzymes remove incorrectly-paired nucleotides.

Question 79

Short, noncoding, guanine-rich DNA sequences found at the ends of chromosomes are called telomeres.

Question 80

Okazaki fragments are complementary to the leading strand of DNA.