Deck 6: DNA Structure, Replication, and Recombination

Question 1

The molecule of heredity is

A)RNA.
B)DNA.
C)protein.
D)carbohydrate.
E)None of the choices is correct.

Answer 1

DNA.

Question 2

The step in DNA replication in which the proteins connect the correct sequence of nucleotides into a continuous new strand is called

A)initiation.
B)elongation.
C)termination.
D)translation.
E)translocation.

Answer 2

elongation.

Question 3

The four subunits that compose DNA are called

A)phosphodiesters.
B)proteins.
C)nucleotides.
D)nucleosides.
E)polymers.

Answer 3

nucleotides.

Question 4

The step in DNA replication in which the replication proteins open up the double helix and prepare for complementary base pairing is called

A)initiation.
B)elongation.
C)termination.
D)translation.
E)translocation.

Question 5

In the Hershey and Chase experiment designed to determine the molecule of heredity, what was radiolabeled with ³⁵S?

A)protein
B)DNA
C)RNA
D)rRNA

Question 6

The step in DNA replication in which two replication forks moving in opposite directions may meet is called

A)initiation.
B)elongation.
C)termination.
D)translation.
E)translocation.

Question 7

Which one of the following is not an element found in DNA?

A)oxygen
B)sulfur
C)nitrogen
D)phosphorous
E)hydrogen

Question 8

_______ -form DNA spirals to the right and is the major form of naturally occurring DNA molecules.

A)A
B)B
C)D
D)Y
E)Z

Question 9

During the S phase of interphase, the state of the DNA can be described as

A)a single continuous linear double helix.
B)a double helix replicated semiconservatively.
C)a double helix replicated conservatively.
D)a triple helix replicated semiconservatively.

Question 10

DNA is localized mainly in the

A)cell membrane.
B)endoplasmic reticulum.
C)vacuoles.
D)chromosomes.

Question 11

Which of the following is not true of DNA?

A)It is acidic.
B)It contains deoxyribose.
C)It is found in cell nuclei.
D)It contains phosphate.
E)It contains amino acids.

Question 12

X-ray data showed that the spacing between repeating units along the axis of the DNA helix is

A)2.0 angstroms.
B)3.4 angstroms.
C)20 angstroms.
D)34 angstroms.

Question 13

During complementary base pairing, enzymes join the base's nucleotide to the preceding nucleotide by a(n) __________bond.

A)hydrogen
B)ionic
C)phosphodiester
D)electrostatic

Question 14

The polarity of DNA synthesis is

A)5 $\rarr$ 3'.
B)3' $\rarr$ 5'.
C)5' $\rarr$ 2'.
D)2' $\rarr$ 5'.

Question 15

The nucleotide that is present in RNA but not DNA is

A)thymine.
B)uracil.
C)adenine.
D)cytosine.
E)guanine.

Question 16

DNA replication occurs through a _________process.

A)conservative
B)semiconservative
C)dispersive
D)transformative

Question 17

________ bonds are responsible for the chemical affinity between A and T (or G and C) nucleotides.

A)Ionic
B)Covalent
C)Hydrogen
D)Hydrophobic

Question 18

X-ray data showed that the DNA helix undergoes one complete turn every

A)2.0 angstroms.
B)3.4 angstroms.
C)20 angstroms.
D)34 angstroms.

Question 19

During early interphase the state of the DNA can be described as

A)a single continuous linear double helix.
B)a double helix replicated semiconservatively.
C)a double helix replicated conservatively.
D)single-stranded DNA.

Question 20

The ratio of _____ is 1:1.

A)guanine to adenine
B)adenine to thymine
C)cytosine to adenine
D)uracil to cytosine

Question 21

Which term describes the ability of a substance to change the genetic characteristics of an organism?

A)Transcription
B)Translation
C)Transformation
D)Transposition

Question 22

Two strains of S.cerevisae (yeast) are crossed.One has the genotype ABC and the other abc.Five sets of the resultant tetrads are noted below.In which set did a gene conversion event occur?

A)abc, aBc, AbC, aBC
B)abc, abc, ABC, ABC
C)aBc, aBc, AbC, AbC
D)abC, abc, ABc, ABC
E)Abc, Abc, aBC, aBC

Question 23

The full chemical name of DNA is....

A)Derived nucleic acid
B)Dideoxyribonucleic acid
C)Denatured ribonucleic acid
D)Deoxyribonucleic acid

Question 24

If 35% of the bases in a region of the mouse genome are cytosine, what percentage in that region are adenine?

A)15%
B)20%
C)30%
D)35%
E)Cannot be determined

Question 25

Any deviation from the expected 2:2 segregation of parental alleles that results from recombination is known as

A)allelic exchange.
B)gene conversion.
C)crossing over.
D)recombination.
E)DNA replication.

Question 26

How many replication forks depart from an origin of replication?

A)one
B)two
C)three
D)four

Question 27

The process of _________ is extremely important in generating genetic diversity.

A)translation
B)transcription
C)recombination
D)transformation

Question 28

Hershey and Chase relied on ________ to physically separate the infected bacterial cells from the phage ghosts.

A)radioactivity
B)gel filtration
C)ion exchange
D)centrifugation

Question 29

Which of the following is not involved in ensuring the accuracy of a cell's genetic information?

A)redundancy
B)repair enzymes
C)precision of replication machinery
D)DNA polymerase proofreading mechanism
E)restriction endonucleases

Question 30

What radiolabeled substance did Hershey and Chase use to label the protein component of the bacteriophage in their study to determine whether protein or DNA was necessary for phage production?

A)nitrogen
B)carbon
C)sulfur
D)phosphorus
E)iodine

Question 31

Without __________ regions on the DNA during recombination, gene conversion could not occur.

A)homoduplex
B)heteroduplex
C)homotriplex
D)heterotriplex

Question 32

Which term is used to describe the overall 5' to 3' direction of linked nucleotides in a DNA chain?

A)Complementarity
B)Sequence
C)Polarity
D)Primacy

Question 33

Eukaryotic chromosomes have evolved special structures at the ends of chromosomes to ensure the replication of the two ends of linear chromosomes.These structures are called

A)methylases.
B)capping proteins.
C)ligases.
D)telomeres.
E)single-stranded binding proteins.

Question 34

The nicking of DNA that initiates recombination during mitosis may be due to all of the following EXCEPT:
A.instructions from the normal cell cycle program.
B.X-rays.
C.chemical damage.
D.physical damage.
E.radiation.

Question 35

Meselson and Stahl relied on equilibrium density gradient centrifugation in a _______ solution to resolve the DNA containing ¹⁴N from the DNA containing ¹⁵N.

A)radiolabeled phosphate
B)calcium chloride
C)radiolabeled nitrogen
D)sodium acetate
E)cesium chloride

Question 36

The group of enzymes able to relax supercoils in DNA is called

A)primases.
B)helicases.
C)topoisomerases.
D)telomeres.
E)ligases.

Question 37

In eukaryotic cells, replication proceeds from ____ origin(s) of replication.

A)zero
B)one
C)two
D)several
E)many

Question 38

Recombination occurs during meiotic ________.

A)anaphase
B)interphase
C)prophase
D)metaphase

Question 39

Recombination involves the breakage and reunion of DNA molecules from

A)homologous nonsister chromatids.
B)homologous sister chromatids.
C)heterologous nonsister chromatids.
D)heterologous sister chromatids.

Question 40

The protein that progressively unwinds DNA ahead of each replication fork is called

A)primase.
B)helicase.
C)topoisomerase.
D)telomerase.
E)ligase.

Question 41

Which type of virus infects bacterial cells?

A)Retrovirus
B)Reovirus
C)Bacteriophage
D)Bacteriovirus
E)Parvovirus

Question 42

How many origins of replication does the E.coli chromosome contain?

A)None
B)1
C)2
D)Several
E)Many

Question 43

Which of the following types of DNA form left-handed helices?

A)A-DNA
B)B-DNA
C)Z-DNA
D)All of the above

Question 44

Which of the following properties of RNA is most directly responsible for its ability to form complex shapes?

A)The presence of uracil instead of thymine
B)The fact that RNA is primarily double-stranded
C)The relative instability of RNA compared to DNA
D)The fact that RNA is primarily single-stranded
E)The substitution of deoxyribose in DNA with ribose in RNA

Question 45

Which of the following is an example of a protein that can read the sequence of DNA without opening the double helix?

A)RNA polymerase
B)DNA polymerase
C)Helicase
D)Transcription factors
E)Primase

Question 46

Which type of viruses causes polio and AIDS?

A)Retrovirus
B)Reovirus
C)Bacteriophage
D)Bacteriovirus
E)Parvovirus

Question 47

Which protein is needed to lay down a segment of RNA complementary to the DNA before replication can begin?

A)RNA polymerase II
B)Primase
C)Helicase
D)Topoisomerase
E)Ligase

Question 48

With respect to DNA structure, what does polarity refer to?

A)DNA nucleotides can be either positively or negatively charged
B)The phosphate backbone of DNA is negatively charged
C)DNA nucleotides can be charged or uncharged
D)DNA strands have a 5' direction and a 3' direction

Question 49

Which protein relaxes supercoils by nicking the DNA?

A)Topoisomerase
B)Helicase
C)Primase
D)Ligase
E)Telomerase

Question 50

Suppose a region of DNA is 100 bp in length.How many unique sequences could it potentially represent?

A)100⁴
B)4¹⁰⁰
C)400
D)4,000
E)10,000

Question 51

Given the following strand of DNA: 5' CATAGCCTTA 3'
Which of the following sequences is the correct complementary DNA strand?

A)5' CATAGCCTTA 3'
B)3' GTATCGGAAT 5'
C)5' GTATCGGAAT 3'
D)3' GUAUCGGAAU 5'
E)3' CATAGCCTTA 5'

Question 52

Which of the following contains single-stranded DNA as its genetic material?

A)Humans
B)HIV
C)?X174
D)coli

Question 53

Transformation in bacteria results from the uptake of which molecule?

A)RNA
B)DNA
C)Lipid
D)Protein
E)Polysaccharide

Question 54

Exposure of which of the following regions of a molecule of DNA permits the reading of DNA sequence without opening the double helix?

A)Phosphate groups
B)Phosphodiester bonds
C)Major groove
D)Minor groove