chapter 13

Hershey and Chase used _____ to radioactively label the T2 phage's proteins. - 222Ra - 35S - 92U - 14C - 32P

- 35S

The radioactive isotope 32P labels the T2 phage's _____. - protein coat - base plate - head - tail - DNA

- DNA

Which of these is a difference between a DNA and an RNA molecule? - DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars. - DNA contains nitrogenous bases, whereas RNA contains phosphate groups. - DNA is usually double-stranded, whereas RNA is usually single-stranded. - DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids. - DNA contains uracil, whereas RNA contains thymine.

- DNA is usually double-stranded, whereas RNA is usually single-stranded.

Who demonstrated that DNA is the genetic material of the T2 phage? - Darwin and Wallace - Watson and Crick - Franklin - Meselson and Stahl - Hershey and Chase

- Hershey and Chase

Griffith's experiments with S. pneumoniae were significant because they showed that traits could be transferred from one organism to another. What else did he find that was significant? - Heat kills bacteria. - DNA was the genetic material. - The transferred traits were heritable. - A virus made the bacteria pathogenic. - Protein could not be the genetic material.

- The transferred traits were heritable.

During mitosis, centromeres separate and chromatids become individual chromosomes during which phase? - prometaphase - telophase - anaphase - metaphase

- anaphase

The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. - disulfide (S−S) bonds - hydrogen bonds - covalent bonds - ionic bonds

- hydrogen bonds

During _____, the cell grows and replicates both its organelles and its chromosomes. - interfase - mitosis - cytokinesis - prophase

- interfase

The letter A indicates a__ - sugar - nucleotide - nitrogenous base - phosphate group - none of the above

- phosphate group

In his work with pneumonia-causing bacteria and mice, Griffith found that __________. - some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic - the protein coat from pathogenic cells was able to transform nonpathogenic cells - the polysaccharide coat of bacteria caused pneumonia - heat-killed pathogenic cells caused pneumonia

- some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. - uracil ... cytosine - cytosine ... uracil - guanine ... adenine - cytosine ... thymine - thymine ... cytosine

- thymine ... cytosine

In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon. - 2' ... 3' - 1' ... 5' - 2' ... 1' - 1' ... 2' - 1' ... 3'

1' ... 5'

Nucleic acids are assembled in the _____ direction. - 1' to 5' - 5' to 3' - 2' to 3' - 4' to 5' - 5' to 1'

5' to 3'

Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine? 31% 42% 16% 8%

8%

In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules? A = G A = C A + T = G + C A + G = C + T

A + G = C + T

In this activity, you will demonstrate your understanding of antiparallel elongation at the replication forks. Keep in mind that the two strands in a double helix are oriented in opposite directions, that is, they are antiparallel. Drag the arrows onto the diagram below to indicate the direction that DNA polymerase III moves along the parental (template) DNA strands at each of the two replication forks. Arrows can be used once, more than once, or not at all. --> <--

A. --> B. --> C. <-- D. <--

The DNA double helix is composed of two strands of DNA; each strand is a polymer of DNA nucleotides. Each nucleotide consists of a sugar, a phosphate group, and one of four nitrogenous bases. The structure and orientation of the two strands are important to understanding DNA replication. Drag the labels to their appropriate locations on the diagram below. Targets of Group 1 can be used more than once. pink labels: 5' end 3' end blue labels: deoxyribose sugar phosphate group nitrogenous base hydrogen bond

A. 5' end B. hydrogen bond C. 3' end D. deoxyribose sugar E. nitrogenous base F. phosphate group G. 3' end H. 5' end

Comparing the leading and the lagging strands of D N A synthesis, how do they differ? A. The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction. B. The leading strand is synthesized at twice the rate of the lagging strand. C. The leading strand is synthesized in short fragments that are ultimately stitched together, whereas the lagging strand is synthesized continuously. D. The leading strand is synthesized by adding nucleotides to the 3′ end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5′ end.

A. The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

Arrange the following terms in order, from smallest to largest size: nucleosome, metaphase chromosome, histone, 30-nm fiber. A. histone, nucleosome, 30-nm fiber, metaphase chromosome B. nucleosome, histone, 30-nm fiber, metaphase chromosome C. histone, nucleosome, metaphase chromosome, 30-nm fiber D. 30-nm fiber, histone, nucleosome, metaphase chromosome

A. histone, nucleosome, 30-nm fiber, metaphase chromosome

For a science fair project, two students decided to repeat the Hershey and Chase experiment, with modifications. They decided to label the nitrogen of the DNA rather than the phosphate. They reasoned that each nucleotide has only one phosphate and two to five nitrogens. Thus, labeling the nitrogens would provide a stronger radioactive signal than labeling the phosphates. Why won't this experiment work? - Although there are more nitrogens in a nucleotide, labeled phosphates actually have 16 extra neutrons; therefore, they are more radioactive. - There is no radioactive isotope of nitrogen. - Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins. - The phosphate in normal DNA is naturally radioactive.

Amino acids (and thus proteins) also have nitrogen atoms; thus, the radioactivity would not distinguish between DNA and proteins.

you can use Chargaff's rules to predict the percentage of one or more bases in the DNA of a species if at least one value is known. What is the %T in wheat DNA? - Approximately 22% - Approximately 23% - Approximately 28% - Approximately 45%

Approximately 23%

In the accompanying image, a nucleotide is indicated by the letter _____. B A C D

B

Suppose a double-stranded DNA molecule was shown to have 15% adenine bases. What would be the expected percentage of guanine bases in that molecule? A. 15% B. 35% C. 85% D. not enough information

B. 35%

Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA? A. Griffith B. Franklin C. Meselson and Stahl D. Chargaff E. McClintock

B. Franklin

To "sequence" D N A means to A. arrange molecules by their relative sizes B. determine the order of bases in a molecule C. allow two strands to base pair with each other D. replicate D N A as accurately as possible

B. determine the order of bases in a molecule

In Meselson and Stahl's experiment proving semi-conservative DNA replication, they showed that after switching bacteria from heavy to light nitrogen and allowing one round of replication, their DNA consisted of only hybrid DNA. What did they observe after the second round of replication? A. only hybrid DNA B. equal amounts of light and hybrid DNA C. equal amounts of light, hybrid and heavy DNA D. three times as much light as hybrid DNA

B. equal amounts of light and hybrid DNA

Which of the following would typically not be used to clone D N A? A. plasmid vector B. telomerase C. restriction enzyme D. PCR

B. telomerase

In DNA replication in bacteria, the enzyme DNA polymerase III (abbreviated DNA pol III) adds nucleotides to a template strand of DNA. But DNA pol III cannot start a new strand from scratch. Instead, a primer must pair with the template strand, and DNA pol III then adds nucleotides to the primer, complementary to the template strand. Each of the four images below shows a strand of template DNA (dark blue) with an RNA primer (red) to which DNA pol III will add nucleotides. in which image will adenine (A) be the next nucleotide to be added to the primer? A B C D

C

a nitrogenous base is indicated by the letter__ - A - D - B - C

C

Which of these is(are) pyrimidines? - A and B - B and C - B, C, and D - A, B, and C - C, D, and E

C, D, and E

Suppose a 100-base-pair DNA molecule consists of 20% cytosine bases. How many total hydrogen bonds are there holding the two strands together? A. 20 B. 60 C. 120 D. 240

C. 120

D N A replication overall has very high fidelity, but it is not perfect. What is the biological and evolutionary importance of this imperfection? A. It allows for D N A repair to occur. B. It allows for gene cloning. C. It allows for genetic variation. D. It allows for gene editing.

C. It allows for genetic variation.

Which of the following lists of replication enzymes consist only of polymerases? A. helicase, primase, DNA pol III B. ligase, DNA pol I C. primase, DNA pol I, DNA pol III D. DNA pol I, DNA pol III, helicase

C. primase, DNA pol I, DNA pol III

In the late 1950s, Meselson and Stahl grew bacteria in a medium containing "heavy" (radioactive) nitrogen (15N) and then transferred them to a medium containing 14N, which is a nonradioactive form of nitrogen. They then extracted DNA from the bacteria and centrifuged it to separate the DNA of different densities. Which of the results in figure above would be expected after one round of DNA replication in the presence of 14N? - A - B - C - D

D

D N A replication overall has very high fidelity. Which of the following phenomena or processes contributes to this high fidelity? A. base pairing B. proofreading C. mismatch repair D. all of the above

D. all of the above

The backbone of a double stranded DNA molecule consists of which of the following? A. Van der Waals interactions B. hydrogen bonds C. purine-pyrimidine base-pairs D. antiparallel sugar-phosphate polymers

D. antiparallel sugar-phosphate polymers

Imagine a bacterial cell with a mutation that renders D N A Pol I completely nonfunctional (note that this would be a lethal mutation). What, precisely, would go wrong with replication in this cell? A. inability to unwind double helix B. inability to prime replication C. inability to extend the length of leading and lagging strands D. inability to replace primers

D. inability to replace primers

Which of the following correctly matches each gene tool with its function? A. restriction enzyme: amplify; PCR: cut; CRISPR-cas9: edit B. restriction enzyme: edit; PCR: amplify; CRISPR-cas9: cut C. restriction enzyme: cut; PCR: edit; CRISPR-cas9: amplify D. restriction enzyme: cut; PCR: amplify; CRISPR-cas9: edit

D. restriction enzyme: cut; PCR: amplify; CRISPR-cas9: edit

In trying to determine whether DNA or protein was the genetic material, Hershey and Chase made use of which of the following facts about these two types of molecules? - DNA contains phosphorus, whereas protein does not. - DNA contains nitrogen, whereas protein does not. - DNA contains sulfur, whereas protein does not. - DNA contains purines, whereas protein includes pyrimidines.

DNA contains phosphorus, whereas protein does not.

During DNA replication in E. coli, which of the following enzymes removes the RNA nucleotides from the primer and adds equivalent DNA nucleotides to the 3' end of Okazaki fragments? - helicase - ligase - DNA polymerase I - DNA polymerase III

DNA polymerase I

Which enzyme in E. coli catalyzes the elongation of a DNA strand in the 5'→3' direction? - DNA polymerase III - primase - DNA ligase - topoisomerase

DNA polymerase III

DNA replication is said to be semiconservative. What does this mean? - One of the two resulting double helices is made of two old strands, and the other is made of two new strands. - Half of the old strand is degraded, and half is used as a template for the replication of a new strand. - Each new double helix consists of one old and one new strand. - One strand of the new double helix is made of DNA, and the other strand is made of RNA. - The old double helix is degraded, and half of its nucleotides are used in the construction of two new double helices.

Each new double helix consists of one old and one new strand.

So Frederick Griffith is the scientist that proved that DNA was the genetic material in bacteria True False

False

Who conducted the X-ray diffraction studies that were key to the discovery of the structure of DNA? - Chargaff - McClintock - Meselson and Stahl - Griffith - Franklin

Franklin

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? - It joins Okazaki fragments together. - It catalyzes the lengthening of telomeres. - It unwinds the parental double helix. - It synthesizes RNA nucleotides to make a primer.

It joins Okazaki fragments together.

What is the function of helicase in DNA replication? - It joins together Okazaki fragments. - It adds nucleotides to the new strand in the 5' to 3' direction. - It untwists the double helix and separates the two DNA strands. - It relieves strain from twisting of the double helix as it is unwound. - It checks for errors in the newly synthesized DNA strand.

It untwists the double helix and separates the two DNA strands.

Which of the following statements describes one difference between DNA replication in prokaryotes and DNA replication in eukaryotes? - Prokaryotic chromosomes have histones, whereas eukaryotic chromosomes do not. - Prokaryotes produce Okazaki fragments during DNA replication, but eukaryotes do not. - Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many. - The rate of elongation during DNA replication is slower in prokaryotes than in eukaryotes.

Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.

In the Hershey and Chase experiment that helped confirm that DNA, not protein, was the hereditary material, what was the key finding? - Radioactively labeled phosphorus was present inside the infected bacteria. - Radioactively labeled carbon was present inside the infected bacteria. - Radioactively labeled phosphorus was found outside of the infected bacteria. - Radioactively labeled sulfur was present inside the infected bacteria. - Radioactively labeled sulfur was found outside of the infected bacteria.

Radioactively labeled phosphorus was present inside the infected bacteria.

What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA? - The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. - Base pairings create unequal spacing between the two DNA strands. - One strand contains only purines and the other contains only pyrimidines. - The twisting nature of DNA creates nonparallel strands.

The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.

If a cell were unable to produce histone proteins, which of the following effects would likely occur? - DNA polymerase I would not function properly. - Spindle fibers would not form during prophase. - The cell's DNA couldn't be packed into its nucleus. - Expression of other genes would compensate for the lack of histones.

The cell's DNA couldn't be packed into its nucleus.

Which of the following statements correctly describes how the leading and the lagging strands of DNA formed during DNA replication differ? - The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction. - The lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together. - The leading strand is synthesized at twice the rate of the lagging strand. - The leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end.

The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.

DNA is a self-replicating molecule. What accounts for this important property of DNA? - Replication is thermodynamically spontaneous and requires no enzymes. - The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C. - Its two strands are held together by easily broken covalent bonds.

The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C.

Which of the following statements correctly describes one of Chargaff's rules regarding DNA? - The percentages of adenine and thymine are roughly equal, as are the percentages of guanine and cytosine in the DNA of a given species. - DNA has a double helical structure. - The percentages of adenine and cytosine are roughly equal, as are the percentages of guanine and thymine in the DNA of a given species. - DNA base composition does not vary between species.

The percentages of adenine and thymine are roughly equal, as are the percentages of guanine and cytosine in the DNA of a given species.

Individuals with the disorder xeroderma pigmentosum are hypersensitive to sunlight. What function is impaired in their cells? - They cannot repair thymine dimers. - They cannot replicate DNA. - They cannot undergo mitosis. - They cannot exchange DNA with other cells.

They cannot repair thymine dimers.

Which of the following statements most accurately describes transformation in bacteria? - Transformation is the creation of a strand of RNA from a DNA molecule. - Transformation is the assimilation of external DNA into a cell. - Transformation is the creation of a strand of DNA from an RNA molecule. - Transformation is the infection of cells by a phage DNA molecule.

Transformation is the assimilation of external DNA into a cell.

Tables like the one shown here are useful for organizing sets of data representing a common set of values (in this case, percentages of A, G, C, and T) for a number of different samples (in this case, species). Does the distribution of bases in sea urchin DNA and salmon DNA follow Chargaff's rules? - No, because %A + %T does not equal %G + %C in both species. - No, because %A is higher than %T, and %G is higher than %C in both species. - Yes, because the %A + %T is greater than the %G + %C in both species. - Yes, because the %A approximately equals the %T and the %G approximately equals the %C in both species.

Yes, because the %A approximately equals the %T and the %G approximately equals the %C in both species.

This could be the order of experiments using electrophoresis in your lab: - extract DNA, restrict DNA with restriction enzymes, run gel, expose stained DNA fragments to UV light - extract DNA, run gel, restrict DNA with restriction enzymes, expose DNA fragments to UV light, stain DNA fragments - extract DNA, run gel, stain DNA fragments, expose them to UV light

extract DNA, restrict DNA with restriction enzymes, run gel, expose stained DNA fragments to UV light

During DNA replication, which of the following enzymes separates the DNA strands during replication? - helicase - ligase - DNA polymerase III - DNA polymerase I

helicase

_______________ is the enzyme that unwinds DNA and the ____________ keep DNA open so ___________ can copy DNA. The enzyme ____________ creates a RNA primer to initiate replication which is later removed by __________________ and the new added DNA nucleotides are joined by the ______________. - ligase, helicase, DNA polymerase I, DNA polymerase III, primase, ssbp - helicase, ssbp, DNA polymerase I, primase, DNA polymerase III, ligase - ligase, helicase, DNA polymerase III, primase, DNA polymerase I, ssbp - helicase, ssbp, DNA polymerase III, primase, DNA polymerase I, ligase

helicase, ssbp, DNA polymerase III, primase, DNA polymerase I, ligase

Which of the following modifications is most likely to alter the rate at which a DNA fragment moves through a gel during electrophoresis? - leaving the length of the DNA fragment the same - radioactively labeling the cytosine bases within the DNA fragment - altering the nucleotide sequence of the DNA fragment without adding or removing nucleotides - increasing the length of the DNA fragment

increasing the length of the DNA fragment

As a result of its involvement in a chemical reaction, an enzyme - donates amino acid R groups to its reactants, turning them into products. - donates electrons to its reactants, turning them into products. - is unchanged by the reactants or products. - receives functional groups from reactants, allowing them to become products.

is unchanged by the reactants or products.

After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained _____, which demonstrated that _____ is the phage's genetic material. - labeled protein ... DNA - labeled DNA ... DNA - labeled DNA .... protein - labeled protein .... protein - labeled DNA ... labeled protein

labeled DNA ... DNA

In nucleotide excision repair, damaged DNA is excised by what enzyme(s)? - nuclease - primase - ligase - helicase - DNA polymerases

nuclease

In which order do the necessary enzymes act to repair a thymine dimer by nucleotide excision repair? - helicase, DNA polymerase, DNA ligase - DNA ligase, nuclease, helicase - nuclease, DNA polymerase, RNA primase - nuclease, DNA polymerase, DNA ligase

nuclease, DNA polymerase, DNA ligase

This is an image of a(n) _____. - nucleotide - thiol - nucleic acid - amino acid - none of the above

nucleotide

What process repairs damage to a preexisting double helix? - nucleotide excision repair - operon repair - transformation - mismatch repair - proofreading

nucleotide excision repair

E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment? - one low-density and one intermediate-density band - one high-density and one intermediate-density band - one intermediate-density band - one high-density and one low-density band

one low-density and one intermediate-density band

This is an image of a _____. - protist - moneran - bacterium - phage - red blood cell

phage

What is the function of topoisomerase? - unwinding of the double helix - adding methyl groups to bases of DNA - elongating new DNA at a replication fork by adding nucleotides to the existing chain - relieving strain in the DNA ahead of the replication fork

relieving strain in the DNA ahead of the replication fork

Which of the following molecule(s) help(s) to hold the DNA strands apart while they are being replicated? - single-strand binding proteins - primase - ligase - DNA polymerase

single-strand binding proteins

You can tell that this is an image of a DNA nucleotide and not an RNA nucleotide because you see a _____. - sugar with two, and not three, oxygen atoms - phosphate group, not a uracil - double-stranded molecule, not a single-stranded molecule - thymine nitrogenous base, not a uracil nitrogenous base - uracil nitrogenous base, not a thymine nitrogenous base

sugar with two, and not three, oxygen atoms

What are the repetitive DNA sequences present at the ends of eukaryotic chromosomes called? - polypeptides - centromeres - chromomeres - telomeres - sarcomeres

telomeres

Which of the following characteristics of the structure of DNA was determined directly from X-ray diffraction photographs of crystallized DNA? - the double helical structure - the frequency of A versus T nucleotides - the length of a given DNA molecule - the sequence of nucleotides

the double helical structure

Which of the following characteristics of the structure of DNA allows it to carry a large amount of hereditary information? - phosphate-sugar backbones - the sequence of bases - different five-carbon sugars - complementary pairing of bases

the sequence of bases

Which of these nitrogenous bases is found in DNA but not in RNA? - thymine - guanine - adenine - cytosine - uracil

thymine