Deck 14: Dna: the Genetic Material

Question 1

DNA primase

A)creates a short RNA primer that is complementary to an RNA template.
B)creates a short DNA primer that is complementary to an RNA template.
C)creates a short DNA primer that is complementary to a DNA template.
D)creates a short DNA template that is complementary to an RNA primer.
E)creates a short RNA primer that is complementary to a DNA template.

Answer 1

E

Question 2

Based on their experiment with T2 bacteriophages,Hershey and Chase concluded that

A)DNA replication is semiconservative.
B)the phage coat contains the genetic material.
C)DNA functions as the genetic material.
D)A always pairs with T and G always pairs with C.
E)virulent bacteria can transform nonvirulent bacteria.

Answer 2

C

Question 3

The synthesis of a growing strand of DNA is carried out by adding nucleotides to the ________ end of an existing strand.

A)2'
B)3'
C)5'
D)1'

Answer 3

B

Question 4

Which is not a component of nucleic acids?

A)organic nitrogenous base
B)pentose sugar
C)phosphate
D)sulfur

Question 5

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.

Question 6

The chemical bond connecting one nucleotide with the next along one strand of a DNA molecule is called a

A)glycosidic bond.
B)hydrogen bond.
C)phosphate bond.
D)phosphodiester bond.
E)peptide bond.

Question 7

As the two strands of DNA are unraveled,which enzyme relieves the strain on the two strands?

A)DNA polymerase
B)DNA ligase
C)DNA gyrase
D)DNA endonuclease
E)DNA exonuclease

Question 8

Who originally discovered the process of bacterial transformation?

A)Watson and Crick
B)Chargaff
C)Hershey and Chase
D)Griffith
E)Meselson and Stahl

Question 9

Because the two strands of a DNA molecule are ________ to each other,either one can be used as a template to reconstruct the other.

A)identical
B)antiparallel
C)bound
D)complementary

Question 10

After attaching to a bacterial cell,a bacteriophage typically

A)injects protein into the cell.
B)extracts protein from the cell.
C)injects DNA into the cell.
D)extracts DNA from the cell.
E)transforms the cell into a virulent strain.

Question 11

The method of DNA replication,where each original strand is used as a template to build a new strand,is called the

A)conservative method.
B)semiconservative method.
C)disruptive method.
D)continuous method.
E)replication and amplification method.

Question 12

________ is the genetic material for all cellular organisms and some viruses.

A)RNA
B)DNA
C)Protein
D)Chromatin

Question 13

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.

Question 14

Avery and his coworkers showed that the agent responsible for changing nonvirulent bacteria into virulent bacteria was

A)protein.
B)polysaccharide.
C)DNA.
D)RNA.
E)lipid.

Question 15

Watson and Crick developed a model of DNA in which the two strands twist into the shape of a ________.

A)circle
B)helix
C)double helix
D)double pleated sheet

Question 16

Nucleotides have a phosphate group attached at the ________ carbon atom of the sugar.

A)2'
B)3'
C)5'
D)1'

Question 17

Which enzyme adds new nucleotides to the end of a growing strand?

A)ligase
B)polymerase
C)gyrase
D)helicase
E)endonuclease

Question 18

DNA consists of two antiparallel strands of nucleotides held together by

A)peptide bonds.
B)covalent bonds.
C)ionic bonds.
D)hydrogen bonds.

Question 19

Viruses that attack bacteria are called

A)phages
B)proviruses
C)virulent
D)lytic

Question 20

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.

Question 21

Information obtained by Franklin from X-ray crystallography on DNA suggested that it is shaped like a

A)helix.
B)ribbon.
C)hollow cylinder.
D)pleated sheet.
E)icosahedron.

Question 22

Eukaryotic organisms speed up the process of DNA replication by

A)shortening the initiation phase.
B)producing several sliding clamp complexes which provide more binding sites for DNA pol III.
C)using DNA gyrase to unravel the double helix rather than DNA helicase.
D)using multiple origins of replication on each chromosome.

Question 23

In 1952,Hershey and Chase confirmed Avery's (1944)conclusion that

A)proteins are the repositories for hereditary information.
B)DNA is the repository for hereditary information.
C)RNA is the repository for hereditary information.
D)each DNA molecule is composed of two strands that are twisted into a double helix.
E)the replication of DNA is semiconservative.

Question 24

The two strands of a DNA molecule contain nitrogen bases which are

A)identical.
B)parallel.
C)complementary.
D)proportionate.
E)random.

Question 25

Endonucleases and exonucleases are enzymes that can remove nucleotides from a polynucleotide chain.An endonuclease removes nucleotides ________ while an exonuclease removes nucleotides ________.

A)from the 5' end of the chain; from the 3' end of the chain
B)from the 3' end of the chain; from the 5' end of the chain
C)internally; from the ends of the chain
D)from the ends of the chain; internally

Question 26

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'

Question 27

During DNA replication,each new strand begins with a short

A)amino acid primer.
B)lipid primer.
C)hydrophilic primer.
D)DNA primer.
E)RNA primer.

Question 28

During replication,which enzyme unwinds the DNA double helix?

A)DNA primase
B)DNA polymerase I
C)DNA helicase
D)DNA gyrase
E)DNA ligase

Question 29

The double helix model of DNA structure was proposed by

A)Watson and Crick.
B)Griffith.
C)Avery.
D)Franklin.
E)Chargaff.

Question 30

Griffith,a British microbiologist,used bacteria and mice to demonstrate the process of transformation.During transformation,

A)a bacterial chromosome produces an exact copy of itself.
B)the nucleus of a mouse cell repairs itself when damaged by bacterial infection.
C)DNA from an infected mouse cell changes bacteria from a nonpathogenic to a pathogenic form.
D)genetic material is transferred from one bacterial cell to another.
E)a bacterial cell is transformed into a spore during unsuitable environmental conditions.

Question 31

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%

Question 32

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.

Question 33

After DNA replication is complete,each strand of the original molecule is bound to a new complementary strand.This process is known as

A)disruptive replication.
B)conservative replication.
C)semiconservative replication.
D)dispersive replication.
E)stabilizing replication.

Question 34

If a short sequence of DNA is 5' AATTGCCGT 3',its complement is

A)5' AAAACGCCA 3'.
B)3' TTAACGGCT 5'.
C)3' TTAACGGCA 5'.
D)3' TTAAGCCGA 5'.
E)5' TTAACGGCA 3'.

Question 35

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.

Question 36

The replisome has two main subcomponents.They are

A)the replication folk and the sliding clamp subunit.
B)the primosome and the sliding clamp subunit.
C)the replication folk and the DNA pol III enzymes.
D)the DNA pol III enzymes and the sliding clamp subunits.
E)the primosome and the DNA pol III enzymes.

Question 37

In DNA,complementary nitrogen bases are held together by

A)nitrogen bonds.
B)hydrogen bonds.
C)hydrophobic bonds.
D)peptide bonds.
E)phosphodiester bonds.

Question 38

Which of the following statements about DNA replication is false?

A)The two strands are separated.
B)Each existing strand is used as a template for making a new strand.
C)Synthesis of both new strands is in the 5' to 3' direction.
D)The newly synthesized DNA is packaged into one nucleus,and the original DNA is packaged into another nucleus.

Question 39

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

Question 40

Replication of DNA is

A)conservative.
B)redundant.
C)dispersive.
D)semiconservative.
E)semidispersive.

Question 41

Deoxyribose has a carbon atom that is not part of the pentose ring.In a nucleotide,what is attached to this carbon?

A)a nitrogenous base
B)a phosphate group
C)three hydrogen atoms
D)one hydrogen atom

Question 42

Who proposed that in any DNA molecule,A = T and G = C?

A)Hershey and Chase
B)Chargaff
C)Franklin
D)Watson and Crick

Question 43

During DNA replication,DNA pol III synthesizes the lagging strand in segments,called

A)replication fragments.
B)Chargaff's segments.
C)repeating primers.
D)replisomes.
E)Okazaki fragments.

Question 44

Xeroderma pigmentosum (XP)is a rare autosomal recessive disorder.Patients with XP exhibit a cellular hypersensitivity to ultraviolet (UV)radiation,a high incidence of skin cancer and premature aging.Based on these clinical characteristics,what is the most likely cause for this disease?

A)defects in DNA repair
B)defects in DNA replication
C)lack of telomerase activity
D)shortened telomeres

Question 45

If a mutation prevented synthesis of the beta subunit of DNA pol III,which would be most affected?

A)DNA unwinding
B)formation of RNA primers
C)formation of the replication fork
D)processivity
E)removal of RNA primers

Question 46

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

Question 47

Why does DNA pol I carry the number one?

A)It was the first polymerase isolated from E.coli.
B)It is the first polymerase to be activated during DNA replication.
C)It is the only polymerase that has both 3' to 5' and 5' to 3' exonuclease activity.
D)It is the smallest polymerase.

Question 48

Who provided X-ray diffraction photographs of purified DNA fibers that suggested a helical structure with a consistent diameter of about 2 nm and a complete helical turn every 3.4 nm?

A)Hershey and Chase
B)Chargaff
C)Franklin
D)Watson and Crick

Question 49

Avery,MacLeod,and McCarty's experiments revealed that the transforming principle had all of the following properties except

A)its activity was destroyed by treatment with proteases.
B)its activity was unaffected by RNA-digesting enzymes.
C)its activity was unaffected by lipid extraction.
D)its activity was destroyed by treatment with DNA endonucleases.

Question 50

Which of the following DNA sequences is complementary to 5' ATGGTCAGT 3'?

A)5' ATGGTCAGT 3'
B)5' TGACTGGTA 3'
C)5' TACCAGTCA 3'
D)5' ACTGACCAT 3'

Question 51

If a mutation produced helicase that was unable to hydrolyze ATP,DNA replication would be

A)stopped.
B)speeded up.
C)unaffected.
D)more prone to errors.

Question 52

In which cells would you expect to find the highest level of telomerase?

A)muscle cells
B)adipose tissue cells
C)neurons
D)cells that replenish the lining of the gut

Question 53

In DNA,a purine must always pair with a pyrimidine and vice versa in order to ensure that

A)the distance between the two phosphodiester backbones remains constant.
B)the two strands are antiparallel.
C)the distance between one base pair and the next remains constant.
D)each base pair is held together by three hydrogen bonds.

Question 54

Who demonstrated that phage genetic material is DNA and not protein?

A)Hershey and Chase
B)Chargaff
C)Franklin
D)Watson and Crick
E)Avery,MacLeod,and McCarty

Question 55

I think the proactive stance is a better attitude to promote than after-the-fact worrying! When planning a long week of sunbathing on the beach,What type of DNA damage should sunbathers be aware of before hitting the beach?

A)photolyase-induced mutations
B)decreased telomere length
C)thymine dimers
D)activation of uvr A,B,and C genes

Question 56

You are asked to give a classroom demonstration of DNA supercoiling.To do so,you take two different colored pieces of rubber tubing,twist them very tightly and excessively around each other and join the ends of the tubing appropriately.Next,you relieve the supercoiling by breaking one strand and unwinding it.In this demonstration,the breaking and unwinding to relieve the supercoiling simulates the action of

A)exonucleases.
B)polymerases.
C)ligases.
D)topoisomerases.
E)primases.

Question 57

In Griffith's experiments,

A)mice infected with live nonvirulent bacteria developed pneumonia and died.
B)nonvirulent bacteria transformed the virulent bacteria into a nonvirulent variety.
C)mice infected with heat-killed virulent bacteria and live nonvirulent bacteria developed pneumonia and died.
D)mice infected with heat-killed virulent bacteria and heat-killed nonvirulent bacteria developed pneumonia and died.

Question 58

During DNA replication,which enzyme removes the RNA primers and then fills in the gap?

A)DNA pol I
B)DNA primase
C)DNA pol III
D)DNA ligase

Question 59

Who proposed that the structure of DNA is a double helix with two polynucleotide chains running in opposite directions and held together by hydrogen bonding between pairs of nitrogenous bases?

A)Hershey and Chase
B)Chargaff
C)Franklin
D)Watson and Crick
E)Meselson and Stahl

Question 60

You are asked to participate in a clinical trial for a new drug that can activate telomerase.Which of the following is a likely risk of such a drug?

A)decreased capacity for tissue repair
B)increased vulnerability to cancer
C)premature aging
D)decreased telomere length

Question 61

The ends of linear chromosomes that maintain chromosome integrity are called

A)telomeres
B)the replisome
C)thymine dimers
D)kinetochores
E)kinetin

Question 62

You take a sample of bacteria with DNA that contains only ¹⁴N and allow them to replicate in a medium that contains only ¹⁵N.After 3 rounds of replication,what percent of the DNA molecules will contain one strand with only ¹⁴N and one strand with only ¹⁵N? Enter your answer as a whole number without the percent sign.For example,5% would be entered as 5 and 37% would be entered as 37.

Question 63

You decide to repeat the Meselson-Stahl experiment,except this time you plan to grow the E.coli cells on light ¹⁴N medium for many generations and then transfer them to heavy ¹⁵N medium and allow them to grow for 2 additional generations (2 rounds of DNA replication).If the conservative model of DNA replication was correct,what is the expected distribution of DNA in the density gradient after two rounds of replication?

A)One band of intermediate density.
B)One band of light density.
C)One band of heavy density.
D)One band of light density and one band of heavy density.
E)One band of light density and one band of intermediate density.

Question 64

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.

Question 65

Suppose a new species of bacterium is discovered.It contains a form of DNA pol III that can add new nucleotides to either the 5' end or the 3' end of an existing strand.All other properties of the enzyme remain unchanged.How would DNA replication in these bacteria differ from normal replication?

A)Both new strands could be synthesized continuously like the leading strand.
B)The same polymerase molecule could synthesize both strands at the same time.
C)Helicase would no longer be required for replication.
D)DNA gyrase would no longer be required for replication.

Question 66

If 16% of the nucleotides in one strand of a DNA molecule contain the base G,what percent of the nucleotides on the complementary strand will also contain the base G?

A)16%
B)8%
C)34%
D)32%
E)It is impossible to determine from the information given.

Question 67

An organism has been found to contain a defective form of photolyase.What function might be impaired in this organism?

A)Lengthening of the tips of chromosomes
B)Repair of DNA damage caused by UV light
C)Stabilization of single-stranded DNA during DNA replication
D)Recognition of damaged DNA by the UvrABC complex

Question 68

You decide to repeat the Meselson-Stahl experiment,except this time you plan to grow the E.coli cells on light ¹⁴N medium for many generations and then transfer them to heavy ¹⁵N medium and allow them to grow for 2 additional generations (2 rounds of DNA replication).If the semiconservative model of DNA replication is correct,what is the expected distribution of DNA in the density gradient after two rounds of replication?

A)One band of intermediate density.
B)One band of intermediate density and one band of light density.
C)One band of intermediate density and one band of heavy density.
D)One band of heavy density and one band of light density.
E)One band of heavy density.