Deck 14: Dna Structure, Replication, and Organization

Question 1

The T2 bacteriophages used in the Hershey and Chase experiment contain ____.

A) DNA only
B) RNA and protein
C) protein, phospholipid, and DNA
D) DNA and protein
E) protein, phospholipid, DNA, and RNA

Answer 1

D

Question 2

The genome of an organism contains 30% adenine. Based on this, you would predict that this organism's genome also contains 30% ____.

A) thymine
B) cytosine
C) each of cytosine and guanine
D) each of thymine and guanine
E) guanine

Answer 2

A

Question 3

The genetic material of all living organisms is ____.

A) protein
B) deoxyribonucleic acid
C) ribonucleic acid
D) glycoprotein
E) polypeptide

Answer 3

B

Question 4

In the Hershey and Chase experiment,³²P was used to label ____ and³⁵S was used to label ____.

A) RNA; protein
B) protein; DNA
C) phospholipids; protein
D) protein; phospholipids
E) DNA; protein

Question 5

If a stretch of human double-stranded DNA contains 47% G and C bases, then ____.

A) it contains 47% A and T bases
B) there are more pyrimidines than purines
C) there are more purines than pyrimidines
D) it contains 53% A and T bases
E) there are no genes in this stretch of DNA

Question 6

The transforming principle described by Griffith in his work with Streptococcus pneumoniae was later shown by Avery, MacLeod, and McCarty to be ____.

A) a polysaccharide capsule
B) a phospholipid
C) protein
D) RNA
E) DNA

Question 7

James Watson, Francis Crick, Rosalind Franklin, and Maurice Wilkins are recognized for their contributions to the discovery of the ____.

A) presence of nuclein (DNA) in white blood cells
B) role of DNA in cells
C) chemical components of DNA
D) three-dimensional structure of DNA
E) location of DNA in cells

Question 8

What happens when living R strain Streptococcus pneumoniae bacteria are mixed with heat-killed S strain Streptococcus pneumoniae bacteria?

A) The S strain bacteria come back to life.
B) The R strain bacteria are killed, and the S strain bacteria remain dead.
C) The R strain bacteria are transformed into S strain bacteria.
D) The S strain bacteria are transformed into R strain bacteria.
E) The R strain bacteria are killed, and the S strain bacteria come back to life.

Question 9

Adjacent nucleotides on a strand of DNA are connected to each other by a(n) ____.

A) hydrophobic interaction
B) phosphodiester bond
C) hydrogen bond
D) peptide bond
E) ionic bond

Question 10

In the Hershey and Chase experiment, phage-infected bacteria and viral progeny were radioactive following bacterial infection with³²P-labeled viruses. Why?

A) Bacteria had incorporated radioactive proteins into their DNA.
B) Phage DNA labeled with³²P had entered the bacteria and appeared in progeny phages.
C) Viral progeny had used the³²P to build new viral proteins.
D) Bacteria had incorporated radioactive proteins into their cell membranes.
E)³²P was left outside the cell during viral infection.

Question 11

Avery, MacLeod, and McCarty continued Griffith's work with S. pneumoniae and concluded that DNA was the hereditary material. If protein were the hereditary material instead of DNA, what would happen to mice after injection of heat-killed virulent bacteria mixed with live non-virulent bacteria after treatment with protease?

A) The mice would live.
B) The mice would die.
C) The mice would get sick, but recover.
D) The mice would grow tumors.
E) The mice would degrade the protein.

Question 12

Prior to the 1940s, many biologists believed ____, which is composed of 20 different types of ____, was most likely the genetic material.

A) protein; amino acids
B) DNA; amino acids
C) protein; nucleotides
D) DNA; nucleotides
E) RNA; nucleotides

Question 13

Nucleic acids are long chains of ____.

A) amino acids
B) lipids
C) nucleotides
D) sugars
E) peptides

Question 14

The genome of an organism contains 14% guanine; therefore, its genome also contains ____% thymine and ____% cytosine.

A) 86; 14
B) 14; 36
C) 36; 36
D) 14; 86
E) 36; 14

Question 15

When Hershey and Chase labeled viruses with radioactive phosphorus, they concluded that the virus injects DNA and not protein into its host because ____.

A) most of the radioactive protein was inside the bacteria
B) most of the radioactive DNA, but little protein ,was inside the bacteria
C) both radioactive DNA and protein were inside the bacteria
D) neither radioactive DNA nor protein was inside the bacteria
E) entire viruses were inside the bacteria

Question 16

Each DNA nucleotide is composed of ____.

A) a six-carbon sugar, a phosphate group, and one of twenty amino acids
B) a five-carbon sugar, a nitrogenous base, and one of twenty amino acids
C) a five-carbon sugar, a phosphate group, and one of four nitrogenous bases
D) a six-carbon sugar, a nitrogenous base, and one of four amino acids
E) a five-carbon sugar, a phosphate group, and one of four amino acids

Question 17

The alteration of a cell's hereditary type by the uptake of DNA released by the breakdown of another cell is called ____.

A) replication
B) transformation
C) crossing-over
D) excision repair
E) ligation

Question 18

Suppose that you performed a version of the Hershey and Chase experiment, this time using³²P-labeled viruses that insert their double-stranded DNA into the DNA of the cells that they infect. The viral DNA is then treated as part of the cell's own DNA and is replicated during DNA replication and passed onto daughter cells when the cell divides. You infect a population of cells with the³²P-labeled viruses, and then let the infected cells go through two generations of cell divisions. If you then examine the cells, you should find³²P-labeled DNA in ____ of the cells.

A) none
B)  about 1/4
C) about 1/2
D) about 3/4
E) all

Question 19

In their experiments to identify the transforming principle, Avery, MacLeod, and McCarty used enzymes that break down ____.

A) protein, DNA, and RNA
B) protein and RNA only
C) DNA only
D) protein, lipids, and RNA
E) lipids and DNA only

Question 20

Purines and pyrimidines are ____.

A) Okazaki fragments
B) pentose-phosphate backbones
C) nucleic acids
D) phosphate bases
E) nitrogenous bases

Question 21

The width of a DNA double helix ____.

A) is constant
B) is narrower where adenine is present than where cytosine is present
C) is wider where purines are present than where pyrimidines are present
D) varies randomly
E) is wider where pyrimidines are present than where purines are present

Question 22

The active site of DNA polymerase is similar in ____.

A) archaea and bacteria only
B) archaea, bacteria, and eukaryotes
C) archaea and eukaryotes only
D) none of these groups
E) bacteria and eukaryotes only

Question 23

In DNA, the pyrimidines are ____.

A) thymine and cytosine
B) adenine and cytosine
C) adenine and guanine
D) thymine and adenine
E) guanine and thymine

Question 24

Why is DNA ligase most active on the lagging strand during DNA replication?

A) The lagging strands contain more short DNA segments, which are joined together by DNA ligase, than the leading strand.
B) The lagging strand is synthesized more slowly, and DNA ligase speeds up the DNA polymerase.
C) The lagging strand synthesizes DNA in the 3' ->5' direction.
D) The lagging strand requires DNA ligase to couple the RNA primer to the Okazaki fragments.
E) DNA ligase performs the function of RNA primase on the lagging strand.

Question 25

The polynucleotide chain of DNA has polarity: the 5' end has a bound ____, while the 3' end has a bound ____.

A) deoxyribose sugar, ribose sugar
B) adenine, thymine
C) cytosine, guanine
D) hydroxyl group, phosphate group
E) phosphate group, hydroxyl group

Question 26

DNA polymerase ____.

A) synthesizes a short RNA segment to begin DNA replication
B) adds nucleotides to the 5' end of an existing strand to synthesize a new DNA strand
C) adds nucleotides to the 3' end of an existing strand to synthesize a new DNA strand
D) seals nicks between adjacent segments of DNA
E) unwinds the DNA double helix at the origin of replication

Question 27

How are purines distinguished from pyrimidines?

A) Purines are derived from a pair of fused C-N rings, while pyrimidines are derived from a single C-N ring.
B) Pyrimidines are derived from a pair of fused C-N rings, while purines are derived from a single C-N ring.
C) Purines have a carbon-containing ring, while pyrimidines have a nitrogenous ring.
D) Pyrimidines have a carbon-containing ring, while purines have a nitrogenous ring.
E) Purines are found only in DNA, while pyrimidines are found only in RNA.

Question 28

Topoisomerase functions by ____.

A) creating cuts in the DNA to relieve over-twisting and strain ahead of the replication fork
B) binding DNA polymerase to hold it tightly to the template DNA
C) unwinding the DNA double helix to expose the template strands for replication
D) binding the newly synthesized DNA to re-twist it into a double helix after replication
E) reading the DNA template and synthesizing a complementary strand of DNA

Question 29

Figure 14.1
The accompanying figure depicts the result of an experiment to determine how DNA replication occurs. Based on these results, it appears that after replication, each new DNA molecule contains ____.

A) either entirely old DNA strands or entirely new DNA strands
B) one old DNA strand and one new DNA strand
C) entirely new DNA
D) some DNA helix regions from old DNA alternating with some DNA regions from new DNA
E) two strands that are each a mix of old and new DNA

Question 30

Helicase ____.

A) proofreads the newly synthesized DNA
B) relieves over-twisting ahead of the DNA replication fork
C) rewinds the newly synthesized DNA strands into a double-stranded helix
D) unwinds the double-stranded DNA helix
E) binds DNA polymerase to the template strand

Question 31

A DNA double helix has two strands that are held together by ____.

A) hydrogen bonds
B) ionic bonds
C) hydrophobic interactions
D) phosphodiester bonds
E) covalent bonds

Question 32

DNA replication is said to be semiconservative because ____.

A) the number of nucleotides within genes remains constant
B) half of the DNA in a cell comes from one parent, and the other half from the other parent.
C) the same process of DNA replication is used by all organisms
D) the total amount of DNA within an individual remains the same
E) each new DNA molecule is composed of one old strand and one new strand

Question 33

Which nucleotide sequence is complementary to the DNA sequence 5'-GACGTT-3'?

A) 5'-TCATGG-3'
B) 3'-TCATGG-5'
C) 3'-CTGCAA-5'
D) 3'-AGTACC-5'
E) 5'-TTGCAG-3'

Question 34

DNA ligase closes nicks between ____ by forming ____ bonds.

A) nitrogenous bases; hydrogen
B) RNA fragments; noncovalent
C) DNA and RNA fragments; covalent
D) DNA fragments; peptide
E) DNA fragments; covalent

Question 35

In the Meselson-Stahl experiment, bacterial DNA was labeled completely with heavy nitrogen (¹⁵N) and then grown in the presence of light nitrogen (¹⁴N). When only mixed DNA was observed after ONE generation of growth in¹⁴N, what was the conclusion?

A) DNA replication is semiconservative
B) DNA replication is conservative
C) DNA replication is dispersive
D) DNA replication is either semiconservative or dispersive
E) DNA replication is either semiconservative or conservative

Question 36

The two strands of a DNA double helix are said to be antiparallel. This means that ____.

A) the 5' end of one strand is directly paired with the 5' end of the other strand
B) since the double helix twists, it is not perfectly parallel
C) one strand has a negative charge, and the other strand has a positive charge
D) the 5' end of one strand is directly paired with the 3' end of the other strand
E) both strands have a negative charge

Question 37

A short RNA chain is synthesized as the first nucleotides in a new DNA strand by the enzyme ____ to provide a ____ for DNA elongation.

A) topoisomerase; 3' hydroxyl group
B) primase; 3' hydroxyl group
C) primase; 5' hydroxyl group
D) DNA polymerase; 5' phosphate group
E) DNA polymerase; 3' hydroxyl group

Question 38

Which statement correctly describes DNA base pairing?

A) Two hydrogen bonds bind A and T; three hydrogen bonds bind G and C.
B) Two hydrogen bonds bind A and C; three hydrogen bonds bind T and G.
C) Two hydrogen bonds bind G and C; three hydrogen bonds bind A and T.
D) Two hydrogen bonds bind A and T, and two hydrogen bonds bind G and C.
E) Three hydrogen bonds bind A and C, and three hydrogen bonds bind T and G.

Question 39

In DNA, the purines are ____.

A) thymine and cytosine
B) adenine and cytosine
C) adenine and guanine
D) thymine and adenine
E) guanine and thymine

Question 40

Wilkins and Franklin studied the structure of DNA using ____.

A) molecular scale models of nucleotides
B) X-ray diffraction
C) computer-assisted graphics
D) electron microscopy
E) light microscopy

Question 41

During DNA replication, nucleosomes must ____ ahead of the replication fork and ____ after DNA is replicated.

A) disassemble; reassemble
B) reassemble; disassemble
C) unwind DNA; disassociate
D) synthesize primers; proofread
E) cut DNA; ligate DNA

Question 42

In humans, telomerase ____.

A) adds telomere repeats in some human cells
B) removes telomere repeats in all human cells
C) adds telomere repeats in all human cells
D) removes telomere repeats in some human cells
E) transcribes telomere repeats in some human cells

Question 43

During normal DNA replication, part of the sequence at the ends of linear chromosomes is not copied into the new DNA strands because ____.

A) DNA ligase cannot join pieces at the end of a chromosome
B) RNA primers at the beginning of a new strand cannot be replaced with DNA
C) those ends are Okazaki fragments that are lost
D) cells do not need the DNA at the ends of chromosomes
E) the ends of chromosomes are made of protein, not DNA

Question 44

Reiji Okazaki discovered what are now called "Okazaki fragments" produced during DNA replication. These fragments are ____.

A) short lengths of new DNA on the leading strand
B) RNA primers on the lagging strand
C) RNA primers on both the lagging and leading strand
D) short lengths of new DNA on the lagging strand
E) RNA primers on the leading strand

Question 45

Proofreading by ____ corrects errors that occur during DNA replication.

A) DNA polymerase
B) primase
C) telomerase
D) DNA ligase
E) helicase

Question 46

The nucleosome core particle consists of ____.

A) two chromosomes linked together
B) RNA wrapped around an eight-protein histone complex
C) DNA wrapped around an eight-protein histone complex
D) DNA associated with the nuclear envelope
E) DNA replication enzymes associating to form the replisome

Question 47

Individuals with xeroderma pigmentosum inherit a faulty DNA repair mechanism. As a consequence, ____.

A) they are sterile
B) their cells have no proofreading abilities during DNA replication
C) Okazaki fragments produced during DNA replication cannot be joined
D) they easily develop skin cancer when exposed to sunlight
E) their telomeres are shorter than average

Question 48

The energy to form the new bonds between nucleotides in a growing DNA strand is provided primarily by ____.

A) unwinding of the DNA double helix
B) hydrolysis of pyrophosphate
C) breaking hydrogen bonds between base pairs
D) DNA helicase
E) forming hydrogen bonds between base pairs

Question 49

Imagine that a cell contains a genetic mutation in the gene encoding the primase enzyme, rendering it unable to synthesize RNA strands. Assuming that all of the other enzymes directly involved in DNA replication are still functional in these cells, how much of the DNA replication process would you expect to see in these cells?

A) The leading strand would be synthesized, but not the lagging strand.
B) No part of the DNA replication process could occur.
C) The DNA helix would be unwound by helicase, but no new strands will be produced.
D) Both the leading and lagging strand would be synthesized, but pieces of discontinuous strands would not be joined together.
E) DNA replication would still proceed completely since RNA strands are not part of the final product of DNA replication.

Question 50

Telomeres are found ____.

A) in the middle of chromosomes
B) at replication origins
C) where DNA strands are joined together
D) within genes
E) at the ends of chromosomes

Question 51

Adding nucleotides onto a growing DNA strand during DNA replication in cells occurs in ____.

A) the 5' ->3' direction for the leading strand and the 3' ->5' direction on the lagging strand
B) either the 5' ->3' direction or the 3' ->5' direction on both strands, depending on where replication begins
C) the 5' ->3' direction only
D) the 3' ->5' direction for the leading strand and the 5' ->3' direction on the lagging strand
E) the 3' ->5' direction only

Question 52

Nucleosomes are best described as ____.

A) prokaryotic DNA associated with nonhistone proteins
B) eukaryotic DNA associated with histone proteins
C) prokaryotic DNA associated with histone proteins
D) eukaryotic DNA associated with nonhistone proteins
E) associated histone and nonhistone proteins

Question 53

When DNA is replicated, ____.

A) parental histones are degraded and entirely replaced by new histones
B) DNA is permanently freed from histone binding
C) new histone proteins are also produced
D) new histone proteins are not needed
E) the number of histones that bind to each DNA molecule is halved

Question 54

In eukaryotes, the DNA molecule that comprises a chromosome is ____ and has ____ replication origin.

A) circular, one
B) circular, more than one
C) linear, more than one
D) linear, one
E) linear, no

Question 55

The components of nucleosomes is(are) ____.

A) DNA only
B) DNA, RNA, and protein
C) DNA and RNA
D) RNA and protein
E) DNA and protein

Question 56

Without proofreading, the rate of DNA replication errors in bacteria and eukaryotes is as high as one for every ____ nucleotides assembled.

A) 10 to 100
B) 100,000 to 1,000,000
C) 1,000 to 10,000
D) 10,000,000 to 100,000,000
E) 100,000,000 to 1,000,000,000

Question 57

After DNA repair enzymes remove an incorrect nucleotide resulting from a replication error, ____ is/are needed to complete the repair.

A) primase, DNA polymerase, and DNA ligase
B) DNA polymerase
C) DNA polymerase and DNA ligase
D) primase and DNA ligase
E) primase and DNA polymerase

Question 58

In prokaryotes, the DNA molecule that makes up a chromosome is ____ and has ____ replication origin.

A) circular; one
B) circular; more than one
C) linear; more than one
D) linear; one
E) linear; no

Question 59

Suppose you take a cell from an adult cow and attempt to use it to produce a clone of that cow. If telomerase is not functioning in that cell or in any of the cell's progeny, what would you expect to happen to your clone?

A) The clone will be unable to grow.
B) When the clone matures, it will most likely have cancer.
C) The clone's cells may divide, but after a certain number of generations, cell division will stop.
D) The lack of telomerase should have no effect on the clone.
E) When the clone matures, it will most likely be sterile.

Question 60

During DNA replication, the ____ strand is assembled in the ____ direction as helix unwinding and is synthesized by ____ replication.

A) leading; opposite; continuous
B) lagging; same; discontinuous
C) leading; same; discontinuous
D) lagging; opposite; continuous
E) leading; same; continuous

Question 65

Although Watson and Crick are credited with the discovery of the structure of DNA, they based this discovery on the bench work of many other scientists of the time. Name at least three different pieces of knowledge that Watson and Crick used in their discovery that was based on work from other scientists.

Question 66

Cancer treatments may specifically target rapidly dividing cells by using drugs or chemicals that ____.

A) promote DNA replication only
B) inhibit DNA repair enzymes only
C) inhibit DNA replication only
D) promote DNA replication or inhibit DNA repair enzymes
E) inhibit DNA replication or DNA repair enzymes

Question 67

Variability in offspring is largely a result of ____.

A) mutations
B) nucleosomes
C) Okazaki fragments
D) DNA repairs
E) RNA primers

Question 68

The steps of DNA replication and the enzymes involved are largely conserved amongst bacteria, archaea, and eukaryotes. How can this evolutionary conservation be explained?

Question 69

Avery, MacLeod, and McCarty showed that DNA was the transforming principle by demonstrating that mice survived when injected with a mixture of dead virulent bacteria and live nonvirulent bacteria that were treated with a DNA degrading enzyme. If RNA was the genetic material, what would have been the effect on the mice? Why?

Question 70

In many cancers, the cancerous cells have fully active telomerase enzymes. Explain how this might play a role in enabling cancer cells to keep rapidly dividing.

Question 71

In Hershey and Chase's experiment, why would it not have been suitable to use radioactive nitrogen to label DNA?

Question 72

Describe what happens to the nucleosome during DNA replication.

Question 73

Some research has indicated that increased exercise is linked to increased telomere length in renewable tissues, like blood. Assuming that telomerase levels are not increased by exercise, what might explain the increase in telomere length?

A) DNA replication occurred more frequently in individuals who exercised.
B) Cell division occurred more rapidly in individuals who exercised.
C) Telomerase activity was higher in individuals who exercised.
D) Telomerase activity was lower in individuals who exercised.
E) Fewer DNA replication errors occurred in individuals who exercised.

Question 74

Describe the roles of the following enzymes during DNA replication: ligase, single-stranded binding proteins (SSBs), DNA polymerase III, primase, DNA helicase.

Question 75

Suppose a DNA replication error is not corrected. After two cell divisions, how many of the four daughter cells contain this mutation (assuming that the mistake was never corrected)?

A) none
B) one
C) two
D) three
E) four

Question 76

Cancer cells ____.

A) maintain telomerase function
B) have longer telomeres than normal cells
C) eventually die due to shortening chromosomes
D) have circular chromosomes
E) cannot replicate their DNA

Question 77

What are two main reasons why DNA mutations are so rare?

Question 78

What is the function of the sliding clamp in DNA replication?

A) unwind DNA ahead of the replication fork
B) anchor DNA polymerase to the template strand
C) remove DNA polymerase from the template strand
D) anchor primase to the template strand
E) bind to single stranded DNA to stabilize it before it is replicated

Question 79

What is unlikely to happen if the sliding clamp is nonfunctional?

A) The overall rate of DNA synthesis is low.
B) The DNA polymerase and the template strand of DNA are not properly anchored together.
C) The DNA polymerase detaches from the DNA after only a few polymerizations.
D) Many thousands of polymerizations occur before the DNA polymerase detaches.
E) The rate of DNA replication is low.