chapter fourteen: DNA the genetic material
DNA replication always proceeds by adding new bases to the _______ end of an existing strand. a) 1' b) 2' c) 3' d) 4' e) 5'
3'
Chargaff's rules for the pairing of nitrogen bases is a) A = C and G = T. b) A = T and G = C. c) A = G and C = T. d) A+T = G+C.
a = t and g = c
Telomerase uses which of the following as a template? a) A small DNA fragment b) A short external RNA c) A short internal RNA d) Proteins
a short internal rna
In an aging cell, the activity of telomerase would be a) high b) low
low
Which of the following statements about the repair mechanism involving photolyase is TRUE? a) Photolyase is reduced and the damaged DNA is oxidized. b) Photolyase is oxidized and the damaged DNA is reduced. c) Photolyase hydrolyzes the damaged DNA. d) Photolyase phosphorylates the damaged DNA. e) Photolyase dephosphorylates the damaged DNA.
photolyase is oxidized and the damaged dna is reduced
Damage caused by UV light leading to thymine dimers is corrected during photorepair by the enzyme a) photorepair b) DNA primase c) thyminase d) DNA polymerase
photorepair
DNA replication is said to be a) dispersive. b) semi-conservative. c) conservative. d) liberal. e) inconclusive.
semi-conservative
Match the types of repair mechanisms with how they work: specific a) target a single kind of lesion in DNA and repair that damage b) repair multiple kinds of lesions in DNA, using a single mechanism
target a single kind of lesion in dna and repair that damage
What is the name of the regions at the ends of eukaryotic chromosomes? a) Histones b) Nucleosomes c) Chromatin d) Telomeres
telomeres
chargaff studied the composition of dna from different sources and found that... a) the number of phosphate groups always equals the number of 5-carbon sugars b) the proportion of A equals that of C and the proportion of G equals that of T c) the proportion of A equals that of T and the proportion of G equals that of C d) purines bind to pyrimidines
the proportion of A equals that of T and the proportion of G equals that of C
which of the following is NOT a component of dna? a) the pyrimidine uracil b) 5-carbon sugars c) the purine adenine d) phosphate groups
the pyrimidine uracil
which of the following is NOT part of the watson-crick model of the structure of dna? a) dna is composed of two strands b) the two dna strands are oriented in parallel (5'-to-3') c) purines bind to pyrimidines d) dna forms a double helix
the two dna strands are oriented in parallel (5'-to-3')
Which statement about the Hershey-Chase experiment is false? a) DNA was labeled with radioactive phosphorus. b) Protein was labeled with radioactive sulfur. c) The virus-infected bacteria contained radioactive phosphorus. d) The virus-infected bacteria contained radioactive sulfur.
the virus-infected bacteria contained radioactive sulfur
The double helix model of DNA structure was proposed by a) Watson and Crick. b) Griffith. c) Avery. d) Franklin. e) Chargaff.
watson and crick
True or False. "Proofreading" effectively eliminates all errors during DNA replication.
false. proofreading eliminates some errors
True or False. Error correcting mechanisms during DNA replication cause cells to accumulate errors at a higher rate, which leads to higher levels of deleterious or lethal mutations.
false. error correcting mechanisms cause cells to accumulate errors at a lower rate, which leads to lower levels of mutations
Radiation, UV light, x-rays, and chemicals in the environment can cause mutations in DNA and are therefore referred to as ______.
mutagens
Which of these is not required for DNA replication? a) Nucleotides b) NADPH c) Template d) Polymerase
nadph
If 14% of the nucleotides from a DNA molecule contain the base T, what percent will contain the base G? a) 14% b) 18% c) 28% d) 36% e) 72%
36%
if one strand of a dna is 5' ATCGTTAAGCGAGTCA 3', then the complementary strand would be... a) 5' TAGCAATTCGCTCAGT 3' b) 5' ACTGAGCGAATTGCTA 3' c) 5' TGACTCGCTTAACGAT 3' d) 5' ATCGTTAAGCGAGTCA 3'
5' TGACTCGCTTAACGAT 3'
Which DNA polymerase removes and replaces RNA primer segments in the synthesis of the lagging stand because it has 5' to 3' exonuclease activity. a) III b) II c) I
I
DNA replication in bacteria begins at a) a single origin and proceeds in one direction. b) a single origin and proceeds in both directions. c) two origins and proceeds in both directions. d) many origins and proceeds in one direction.
a single origin and proceeds in both directions
Bacterial DNA is typically replicated as a) 2 replicons b) 2-5 replicons c) a single replicon d) multiple (>10) replicons
a single replicon
Viruses that infect bacteria are known as a) transposons b) retroviruses c) bacteriophages d) sarcomas
bacteriophages
Nucleotides contain a sugar, a phosphate, and a nitrogenous ______.
base
the difference in leading versus lagging strand synthesis is a consequence of... a) only the physical structure of dna b) only the activity of dna polymerase enzymes c) both the physical structure of dna and the action of polymerase enzyme d) the larger size of the lagging strand
both the physical structure of dna and the action of polymerase enzyme
How does UV light and other ionizing radiations damage DNA molecules? a) creating guanine dimers between adjacent guanines in the DNA chain. b) creating adenine dimers between adjacent adenines in the DNA chain. c) creating thymine dimers between adjacent thymines in the DNA chain. d) creating uracil dimers between adjacent uracils in the DNA chain. e) all of these are possible
creating thymine dimers between adjacent thymines in the dna chain
hershey and chase used radioactive phosphorus and sulfur to... a) label dna and protein uniformly b) differentially label dna and protein c) identify the transforming principle d) both b and c are correct
differentially label dna and protein
The lagging strand is replicated with a series of Okazaki fragments and that is why its synthesis is considered to be a) discontinuous. b) continuous. c) bidirectional. d) antiparallel. e) semiconservative.
discontinuous
the meselson and stahl experiment used a density label to be able to... a) determine the directionality of dna replication b) differentially label dna and protein c) distinguish between newly replicated and old strands d) distinguish between replicated dna and rna primers
distinguish between newly replicated and old strands
What enzyme is responsible for repairing thymine dimers using the energy of light? a) DNA photolyase. b) DNA Polymerase c) DNA ligase d) DNA exonuclease e) DNA Polymerase, DNA ligase, and DNA exonuclease
dna photolyase
the basic mechanism of dna replication is semiconservative with two new molecules,... a) each with new strands b) one with all new strands and one with all old strands c) each with one new and one old strand d) each with a mixture of old and new strands
each with one new and one old strand
successful dna synthesis requires all of the following except... a) helicase b) endonuclease c) dna primase d) dna ligase
endonuclease
This type of primase is a combination of RNA polymerase and DNA polymerase that makes short RNA primers and then extends them with DNA to produce the final primer: a) eukaryotic b) archaeal c) bacterial
eukaryotic
True or False. Cells cannot escape exposure to mutagens, but they have evolved systems that enable them to repair all of the damage.
false. cells have evolved systems that enable them to repair some of the damage
what was the key finding from griffith's experiments using live and heat-killed pathogenic bacteria? a) bacteria with a smooth coat could kill mice b) bacteria with a rough coat are not lethal c) dna is the genetic material d) genetic material can be transferred from dead to live bacteria
genetic material can be transferred from dead to live bacteria
What kind of bond do thimine dimers weaken? a) hydrogen bonds b) sulfide bonds c) covalent bonds d) ionic bonds e) all of these choices
hydrogen bonds
the bonds that hold two complementary strands of dna together are... a) hydrogen bonds b) peptide bonds c) ionic bonds d) phosphodiester bonds
hydrogen bonds
What is the correct sequence for DNA replication in E. coli? a) initiation, termination, elongation b) initiation, elongation, termination c) elongation, termination, initiation d) elongation, initiation, termination
initiation, elongation, termination
when mutations that affected dna replication were isolated, two kinds were found. in cultures that were not synchronized, one class put an immediate halt to replication, whereas the other put a much slower stop to the process. the first class affects functions at the replication fork like polymerase and primase. the second class affects functions necessary for... a) elongation on the lagging but not the leading strand b) elongation on the leading but not the lagging strand c) initiation: cells complete replication but cannot start a new round d) the sliding clamp: loss makes the polymerase slower
initiation: cells complete replication but cannot start a new round
Genetic analysis indicates that an unknown organism contains a gene that codes for a defective form of telomerase. Based on this information alone, you can conclude that this organism a) is prokaryotic. b) is eukaryotic. c) has unusually long telomeres. d) has an increased risk of developing cancer.
is eukaryotic
The experiments used to distinguish between the three potential DNA replication mechanisms were performed by a) Franklin. b) Meselson and Stahl. c) Avery, MacLeod, and McCarthy. d) Griffith.
meselson and stahl
The function of telomeres is to a) extend DNA primers b) seal DNA fragments on the lagging strand c) protect the ends of chromosomes
protect the ends of chromosomes
If we think of the DNA double helix as a twisted ladder, what makes up the rungs or steps of the ladder? a) phosphate groups only b) alternating phosphate groups and sugars c) sugars only d) purines and pyrimidines e) phosphate groups and bases
purines and pyrimidines
The site where the two original DNA strands separate and active replication occurs is called the a) replication fork. b) replisome. c) primosome. d) lagging strand. e) sliding clamp subunit.
replication fork
the synthesis of telomeres... a) uses dna polymerase, but without the sliding clamp b) uses enzymes involved in dna repair c) requires telomerase, which does not use a template d) requires telomerase, which uses an internal rna as a template
requires telomerase, which uses an internal rna as a template
DNA replication that leads to the production of double helices with one parental strand and one newly synthesized strand is consistent with a) dispersive replication b) conservative replication c) semiconservative replication
semiconservative replication
Which is not a component of nucleic acids? a) organic nitrogenous base b) pentose sugar c) phosphate d) sulfur
sulfur
if the activity of dna ligase were removed from replication, this would have a greater effect on... a) synthesis on the lagging strand versus the leading strand b) synthesis on the leading strand versus the lagging strand c) priming of dna synthesis versus actual dna synthesis d) photorepair of dna versus dna replication
synthesis on the lagging strand versus the leading strand
one common feature of all dna polymerases is that they... a) synthesize dna in the 3'-to-5' direction b) synthesize dna in the 5'-to-3' direction c) synthesize dna in both directions by switching strands d) do not require a primer
synthesize dna in the 5'-to-3' direction
When a mixture of live nonvirulent bacteria and dead virulent bacteria was injected into mice, Griffith unexpectedly found that the injected mice died. He explained this result by suggesting that the nonvirulent bacteria are being a) activated. b) transformed. c) translated. d) transcribed. e) expressed.
transformed
True or False. All cells that have been examined show multiple pathways for repairing damaged DNA and for reversing errors that occur during replication.
true
What protein cuts the damaged DNA strand? a) UvrB b) UvrC c) UvrD d) UvrA
uvrc
Which protein has a helicase function? a) UvrB b) UvrC c) UvrD d) UvrA
uvrd
Agents that cause mutation are known as a) mutagens b) nucleases c) sarcomas d) carcinomas
mutagens
Guanine forms ______ hydrogen bonds with cytosine.
3
Franklin used x-ray ______ to suggest that DNA has a helical structure.
diffraction
True or False. Many DNA polymerases have 3'-to-5'exonuclease activity that allows "proofreading" and replacement of incorrect bases.
true
Which of the following is a characteristic of double-stranded DNA? a) 2 nanometers in width b) 10 base pairs per turn c) 0.34 nanometers per basepair d) 2 nanometers in width and 10 base pairs per turn e) 2 nanometers in width, 10 base pairs per turn and 0.34 nanometers per basepair
2 nanometers in width, 10 base pairs per turn and 0.34 nanometers per basepair
X-ray diffraction was used to determine that the diameter of a DNA molecule is a) 10 nm b) 1 nm c) 6 nm d) 2 nm
2 nm
Arrange the following proteins in the proper order in which they participate in DNA replication. 1 = Primase 2 = Helicase 3 = Single-strand binding proteins 4 = DNA polymerase I a) 1, 2, 3, 4 b) 1, 3, 2, 4 c) 2, 3, 1, 4 d) 2, 3, 4, 1 e) 2, 4, 3, 1
2, 3, 1, 4
How many hydrogen bonds form between cytosine and guanine in the DNA double helix? a) 3 b) 4 c) 1 d) 2
3
Bacterial replication (for example in E. coli) begins at a) a single origin b) multiple (>3) origins c) 2-3 origins
a single origin
What is a thymine dimer? a) A mutation caused by a chemical mutagen that causes a thymine base to pair with another thymine instead of adenine b) A thymine analogue that can be incorporated into a DNA molecule during replication, leading to mutation c) A location in a DNA molecule where there are two thymine bases in a row d) A site where two adjacent thymine bases become covalently cross-linked to each other
a site where two adjacent thymine bases become covalently cross-linked to each other
Features of the Watson and Crick model include a) a sugar phosphate backbone b) a helical structure c) nitrogenous bases on the outside d) a double stranded structure
a sugar phosphate backbone a helical structure a double stranded structure
Telomerase is unique because it contains a) a DNA molecule. b) an RNA molecule. c) different RNA molecules. d) different DNA molecules. e) both DNA and RNA molecules.
an rna molecule
Match these enzymes involved in DNA replication with their function: polymerase a) unwinds the double helix b) relieves coiling in DNA strands ahead of the replication fork c) makes a 10-12 bp complementary primer to the DNA d) attaches a nucleotide to the 3' end of the DNA strand
attaches a nucleotide to the 3' end of the dna strand
Evaluate the statements below and determine which is the best explanation for why bacteria don't use telomerase. a) Telomerase did not evolve in the prokaryotic lineages. b) Bacteria have an extremely short life span, so they do not need to worry about their chromosomes shortening. c) Bacteria have circular chromosomes that do not shorten. d) Bacteria use a different enzyme that carries out the same function as telomerase. e) None of these adequately explain why bacteria do not use telomerase.
bacteria have circular chromosomes that do not shorten
How is bacterial DNA replication different from eukaryotic DNA replication? a) The result of bacterial DNA replication is two new double stranded DNA molecules that each contain a template strand and a newly synthesized strand, while the result of eukaryotic DNA replication is one newly synthesized double stranded DNA molecule and one DNA molecule that was the original template. b) Bacterial DNA replication involves nucleotides that are not found in eukaryotic DNA replication. c) Bacterial DNA replication moves out from the origin of replication in two directions, while eukaryotic DNA replication moves out from the origin of replication in only one direction. d) Bacterial DNA replication only replicates small pieces of the chromosome, while eukaryotic DNA replication replicates the entire chromosome. e) All of these are differences between bacterial and eukaryotic DNA replication.
bacterial dna replication moves out from the origin of replication in two directions, while eukaryotic dna replication moves out from the origin of replication in only one direction
How is bacterial DNA replication similar to eukaryotic DNA replication? a) Both bacterial and eukaryotic DNA replication has a single origin of replication. b) Both bacterial and eukaryotic DNA replication occurs in a bidirectional manner. c) Both bacterial and eukaryotic DNA replication is semiconservative. d) Both bacterial and eukaryotic DNA replication results in one DNA double helix that was the template and one completely new DNA double helix. e) All of these are similarities between bacterial and eukaryotic DNA replication.
both bacterial and eukaryotic dna replication is semiconservative
Telomeres are related to a) chromosome compaction b) chromosome division c) cellular organization d) cellular aging
cellular aging
Which of the following enzymes involved in DNA replication are found at the replication fork in all three types of cells (bacterial, archaeal, and eukaryotic)? Choose all that apply. a) Telomerase b) Clamp loader c) Primase d) Helicase e) Polymerases f) Sliding clamp
clamp loader primase helicase polymerases sliding clamp
Which of the following statements about the DNA double helix is TRUE? a) Complementary base pairing across the double helix allows information to be transferred via RNA transcription and DNA replication. b) Complementary base pairing allows the production of identical copies of the template strand (or parts of the template strand) via RNA transcription and DNA replication. c) It takes large amounts of energy to separate the double helix because it is held together via covalent bonds d) The 3' end of the double helix terminates in a nitrogenous base on the 3' carbon e) The 5' end of the double helix terminates in a nitrogenous base on the 5' carbon
complementary base pairing across the double helix allows information to be transferred via rna transcription and dna replication
The two main eukaryotic DNA polymerases that extend DNA are a) delta b) alpha c) gamma d) epsilon
delta epsilon
This model of DNA replication suggests that newly synthesized strands of DNA have mixtures of parental and newly synthesized strands of DNA: a) semiconservative b) dispersive c) conservative
dispersive
In order for mismatch repair to occur in a bacterial cell, the enzyme machinery must be able to a) block replication from occurring until the mismatch repair is completed. b) distinguish between the template strand and a newly synthesized strand. c) efficiently find thymine dimers along the DNA strand.
distinguish between the template strand and a newly synthesized strand
Avery, MacLeod, and McCarty determined that the substance responsible for changing live, nonvirulent bacteria into live, virulent bacteria was ______.
dna
Which enzymes did Avery, MacLeod, and McCarty use in order to identify the genetic material? a) lipid digesting enzymes b) DNA digesting enzymes c) protein digesting enzymes d) RNA digesting enzymes
dna digesting enzymes protein digesting enzymes rna digesting enzymes
The enzyme that relieves DNA supercoiling ahead of the replication fork is a) ligase b) DNA gyrase c) helicase d) polymerase
dna gyrase
RNA primers are removed by the action of the enzyme a) DNA pol III. b) DNA pol I. c) primase. d) helicase. e) phophodiesterase.
dna pol I
Which of the following facilitates the reversal of damage to our hereditary material before a permanent mutation can occur? a) RNA polymerase b) Oncogenes c) DNA repair systems d) Mutagens e) Ultraviolet (UV) light
dna repair systems
In their experiments, Avery, MacLeod, and McCarty isolated a substance, which had a transforming activity. Which of the following destroyed that substance's ability to transform bacterial cells? a) DNA-digesting enzymes b) Protein-digesting enzymes c) RNA-digesting enzymes
dna-digesting enzymes
The interaction of two strands of DNA via hydrogen bonds is the a) chromosome b) genome c) double helix
double helix
The genetic material in bacteria is a) double-stranded DNA. b) double-stranded RNA. c) single-stranded DNA. d) single-stranded RNA. e) either double-stranded DNA or double-stranded RNA.
double-stranded dna
An ______ cuts DNA internally and an ______ cuts at the ends of DNA. a) endonuclease; exonuclease b) exonuclease; endonuclease
endonuclease; exonuclease
Based on replication proteins, DNA replication in archaea is most similar to that of a) eukaryotes b) bacteria
eukaryotes
Which of these is not one of the three phases of DNA replication? a) termination b) initiation c) extension d) elongation
extension
True or False. Any agent that decreases the number of mutations below background levels is called a mutagen.
false. any agent that increases the number of mutations is called a mutagen
True or False. Griffith determined that DNA is the substance responsible for bacterial transformation.
false. avery, macleod, and mccarty determined that dna is the substance responsible for bacterial transformation
True or False. During their experiments, Avery, MacLeod, and McCarty discovered that the removal of nearly all protein from their preparation destroyed its transforming activity.
false. avery, macleod, and mccarty discovered the removal of dna destroyed its transforming activity
True or False. Avery, MacLeod, and McCarty were the first scientists to describe the process of bacterial transformation.
false. griffith was the first scientist
In order for mismatch repair to occur in a bacterial cell, the enzyme machinery must be able to distinguish between the template strand and a newly synthesized strand. How is that achieved? a) For a short period of time after replication, the sequence GATC is methylated at the A only on the newly synthesized strand. b) For a short period of time after replication, the sequence GATC is methylated at the C only on the newly synthesized strand. c) For a short period of time after replication, the sequence GATC is methylated at the C only on the template strand. d) For a short period of time after replication, the sequence GATC is methylated at the A only on the template strand.
for a short period of time after replication, the sequence gatc is methylated at the a only on the template strand
In which of the following chromosomal entities are an individual's traits specified? a) Genes b) RNA molecules c) Nucleotides d) Proteins
genes
The enzyme ______ uses ATP to unwind the DNA template.
helicase
The primary purpose of the Meselson and Stahl experiments was to determine a) the structure of DNA. b) the function of DNA. c) how DNA replicates. d) the nature of the genetic material.
how dna replicates
Which of the following best describes the function of telomerase at the telomere? a) It makes special primers that do not need to be removed. b) It synthesizes new DNA without the use of a template. c) It adds new DNA to both strands of the telomere overhang. d) It adds new DNA to the shorter strand of the telomere overhang. e) It adds new DNA to the longer strand of the telomere overhang.
it adds new dna to the longer strand of the telomere overhang
What might result for a eukaryotic organism that lacked functional telomerase? a) It could not initiate DNA replication. b) It could not synthesize proteins. c) It would have shorter chromosomes with every round of mitosis, leading to abnormal cells. d) It would have shorter chromosomes with every round of mitosis, but it would only lose DNA in the telomeric repeat region. e) Its chromosomes would fuse together, and it could not complete mitosis.
it would have shorter chromosomes with every round of mitosis, leading to abnormal cells
During DNA replication, the ______ strand is synthesized continuously while the ______ strand is synthesized as small fragments that are connected to each other to form a continuous strand.
leading; lagging
Match these enzymes involved in DNA replication with their function: primase a) unwinds the double helix b) relieves coiling in DNA strands ahead of the replication fork c) makes a 10-12 bp complementary primer to the DNA d) attaches a nucleotide to the 3' end of the DNA strand
makes a 10-12 bp complementary primer to the dna
DNA primase (choose all that apply) a) makes a primer of RNA complementary to the DNA. b) makes a primer about 10-20 nucleotides in length. c) makes a primer about 200 nucleotides in length d) makes a primer of DNA complementary to the DNA template.
makes a primer of rna complementary to the dna makes a primer about 10-20 nucleotides in length
______ repair is responsible for removing bases that were incorrectly incorporated into DNA during replication.
mismatch
What type of repair mechanisms is responsible for removing bases that were incorrectly inserted into DNA during replication? a) SOS response b) Mismatch repair c) Exonuclease repair d) Photorepair
mismatch repair
Which of the following is required to replicate the lagging strand of DNA? a) Okazaki fragments b) primase c) DNA ligase d) Okazaki fragments and primase e) Okazaki fragments, primase and DNA ligase
okazaki fragments, primase and dna ligase
During semiconservative DNA replication a) one of the new daughter double helix is made of the two original strands, while the other one is made of two new strands b) random portions of each new double helix come from the original molecule or are newly synthesized c) one of the strands in each new double helix comes from the original molecule, and one is newly synthesized.
one of the strands in each new double helix comes from the original molecule, and one is newly synthesized
What is the name of the subunit that acts as the sliding clamp, which keeps the replicating enzyme complex attached to the template in eukaryotic cells. a) PCNA b) Replicon c) DNA polymerase II d) Primase
pcna
If 35S was found in progeny phages rather than 32P, Hershey and Chase would have concluded that a) proteins contain phosphorus. b) DNA contains sulfur. c) phage DNA enters the host cell. d) phage protein enters the host cell. e) phage can kill the E. coli cell.
phage protein enters the host cell
The DNA backbone is composed of (choose all that apply) a) phosphate groups. b) sugars. c) nitrogenous bases. d) amino acids.
phosphate groups sugars
The correct structure of DNA monomers can be presented as a) phosphate-base-sugar. b) phosphate-sugar-base. c) base-phosphate-sugar. d) phosphate-sugar-phosphate-base. e) base-sugar-phosphate-base.
phosphate-sugar-base
Adjacent nucleotides in the same DNA strand are held together by covalent bonds known as ______ bonds.
phosphodiester
Repeating sugar and phosphate units in a single DNA strand make up the a) nucleotides. b) phosphodiester backbone. c) double backbone helix.
phosphodiester backbone
In DNA, consecutive nucleotides are linked via ______ bonds, which are made between the 5' phosphate of one nucleotide and the 3' ______ group of another nucleotide.
phosphodiester; hydroxyl
The enzyme ______ can repair UV damage by binding to a thymine dimer and cleaving it, therefore restoring two thymines.
photolyase
The enzyme DNA ______ synthesizes the RNA primers required by DNA polymerases during replication.
primase
In the replisome, the ______ is composed of primase, helicase, and accessory proteins that prime the lagging strand.
primosome
Match these enzymes involved in DNA replication with their function: gyrase a) unwinds the double helix b) relieves coiling in DNA strands ahead of the replication fork c) makes a 10-12 bp complementary primer to the DNA d) attaches a nucleotide to the 3' end of the DNA strand
relieves coiling in dna strands ahead of the replication fork
Match the types of repair mechanisms with how they work: nonspecific a) target a single kind of lesion in DNA and repair that damage b) repair multiple kinds of lesions in DNA, using a single mechanism
repair multiple kinds of lesions in dna, using a single mechanism
Choose all characteristics of the transforming substance isolated by Avery, MacLeod and McCarty. a) Extracting DNA from the substance did not affect its transforming ability. b) RNA-digesting enzymes did not affect its transforming ability. c) Protein-digesting enzymes did not affect its transforming ability. d) The elemental composition of the substance was very similar to that of DNA. e) DNA-digesting enzymes destroyed its transforming ability.
rna-digesting enzymes did not affect its transforming ability protein-digesting enzymes did not affect its transforming ability the elemental composition of the substance was very similar to that of dna dna-digesting enzymes destroyed its transforming ability
The enzyme ______ contains a small internal piece of RNA, which is used as a template to extend the end of a linear DNA molecule.
telomerase
Short, repeated sequences of DNA are characteristic of a) origins of replication b) telomeres c) DNA polymerase d) nucleases
telomeres
List the three phases of DNA replication: a) termination b) elongation c) duplication d) extension e) initiation
termination elongation initiation
Griffith's experiments were important because they showed a) how genetic material was inherited in bacteria b) that proteins could not be the genetic material of cells c) that the genetic material could be passed from one cell to another d) the true identity of the genetic material
that the genetic material could be passed from one cell to another
DNA polymerases cannot replicate a) the 5' end of circular chromosomes. b) the 3' end of circular chromosomes. c) the 5' end of linear chromosomes. d) the 3' end of linear chromosomes. e) both the 5' and 3' ends of linear chromosomes.
the 3' end of linear chromosomes
Which model for DNA replication suggests that both strands of the double helix remain intact and the new DNA double helix consists of two new DNA strands? a) The conservative model b) The dispersive model c) The semiconservative model
the conservative model
The enzymes in the replisome are active on a) the lagging strand only b) the leading and the lagging strands c) the leading strand only
the leading and the lagging strands
DNA repair mechanisms have likely evolved because a) there is no way for cells to avoid exposure to mutagens b) some cells have to deal with the effects of mutagens while others do not c) DNA polymerase makes a lot of errors
there is no way for cells to avoid exposure to mutagens
Based on his experiments with the bacterium S. pneumoniae, Griffith concluded that the genetic information for virulence was transferred from dead, virulent cells to live, nonvirulent cells, a process he called ______.
transformation
True or False. Agents that damage DNA can lead to mutations.
true
True or False. Although most mutations are harmful, some may be beneficial.
true
True or False. During Griffith's experiments, a nonvirulent form of S. pneumoniae was transformed into a virulent form.
true
True or False. During bacterial transformation, one or more traits of a cell are altered due to the uptake of DNA from the surrounding environment.
true
True or False. In addition to errors that occur during DNA replication, cells are constantly exposed to agents that can damage DNA, such as UV light, X-rays, and chemicals in the environment.
true
Match these enzymes involved in DNA replication with their function: helicase a) unwinds the double helix b) relieves coiling in DNA strands ahead of the replication fork c) makes a 10-12 bp complementary primer to the DNA d) attaches a nucleotide to the 3' end of the DNA strand
unwinds the double helix
Which E. coli genes encode the proteins required to perform excision repair? a) uvrA, uvrB, and uvrC b) polA, excB, and polC c) excA, excB, and excC
uvrA, uvrB, and uvrC
A phage is a type of ______ that infects ______ cells.
virus; bacterial
Franklin determined that the structure of DNA was helical based on a) microscopic analysis b) ball and stick models c) biochemical analysis d) x-ray diffraction analysis
x-ray diffraction analysis
