Deck 4: Linkage, Recombination, and the Mapping of Genes on Chromosomes

Question 1

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.
E) None of the choices are correct.

Answer 1

B

Question 2

The nucleotide that is present in RNA but not DNA is

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

Answer 2

B

Question 3

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 3

B

Question 4

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
E) None of the choices are correct.

Question 5

_______ -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 6

DNA is localized mainly in the

A) cell membrane.
B) endoplasmic reticulum.
C) vacuoles.
D) chromosomes.
E) None of the choices are correct.

Question 7

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 8

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 proteins.

Question 9

Each nucleotide of DNA contains

A) a deoxyribose sugar.
B) a nitrogenous base.
C) a phosphate.
D) all of the choices are correct.
E) a phospholipid

Question 10

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.
E) None of the choices are correct.

Question 11

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.
E) None of the choices are correct.

Question 12

The four subunits that compose DNA are called

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

Question 13

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

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

Question 14

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

A) Ionic
B) Covalent
C) Hydrogen
D) Electro-ionic
E) None of the choices are correct.

Question 15

The polarity of DNA synthesis is

A) 5'→3'
B) 3'→5'
C) 5'→2'
D) 2'→5'
E) None of the choices are correct.

Question 16

The molecule of heredity is

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

Question 17

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

A) protein
B) DNA
C) RNA
D) rRNA
E) None of the choices are correct.

Question 18

DNA replication occurs through a _________ process.

A) conservative
B) semiconservative
C) dispersive
D) transferal
E) None of the choices are correct.

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.
E) None of the choices are correct.

Question 20

The ratio of _____ is 1:1.

A) guanine to adenine
B) adenine to thymine
C) cytosine to adenine
D) uracil to cytosine
E) None of the choices are correct.

Question 21

Why is RNA required for DNA replication?

A) the lagging strand is synthesized as RNA
B) the double helix must be stabilized by RNA
C) DNA polymerase can only add nucleotides to an existing chain
D) single strand DNA must be stabilized as it is synthesized
E) RNA is converted to DNA after synthesis

Question 22

Which of these is true of RNA?

A) it contains thymidine
B) it contains deoxyribose
C) it can form double helices
D) it forms the chromosomes of some bacteria
E) in eukaryotes,it is synthesized semiconservatively

Question 23

What radiolabelled 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) sulphur
D) phosphorus
E) iodide

Question 24

Pyrimidines are a nitrogenous base containing a double ring,while purines contain a single ring.

Question 25

By applying an equation formulated by Shannon,the information content of a polymer such as DNA or protein depends on its:

A) number of monomers in the polymer
B) number of discrete monomers (e.g.number of different bases or amino acids)
C) number of discrete monomers and total number of monomers in the polymer
D) three-dimensional structure of the polymer
E) three-dimensional structure of the polymer and number of discrete monomers

Question 26

A phosphodiester bond joins one nucleotide to another in the DNA polymer.

Question 27

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 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
E) fluorescent imaging

Question 29

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) None of the choices are correct.

Question 30

Prokaryotes have a circular chromosome surrounded by a nuclear membrane.

Question 31

Transformation in bacteria results from the uptake of foreign DNA.

Question 32

The energy for DNA synthesis comes most directly from

A) deoxyribose
B) dNTPs
C) PPi
D) NADH
E) ribose

Question 33

Which of the following is not true of naturally occurring DNA?

A) it can be circular
B) it forms a right-handed helix
C) it contains hydrogen bonds
D) it contains ribose
E) it contains covalent bonds

Question 34

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

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

Question 35

How many replication forks depart from an origin of replication?

A) one
B) two
C) three
D) four
E) None of the choices are correct.

Question 36

The complementary sequence of 5' AATTCGCTTA 3' is

A) 5' AATTCGCTTA 3'.
B) 3' AATTCGCTTA 5'.
C) 5' TAACGCTTAA 3'.
D) 5' TAAGCGAATT 3'.
E) 3' TAAGCGAATT 5'.

Question 37

Who demonstrated that DNA,rather than protein,was the genetic material of bacteria?

A) Avery
B) Watson
C) Meselson
D) Mendel
E) Franklin

Question 38

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

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

Question 39

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) transformation

Question 40

If chromosomal DNA were single stranded,which of the following would be most reduced compared to a double stranded molecule?

A) informational complexity (e.g.the diversity of proteins encoded)
B) informational fidelity (e.g.the consistency of sequence between generations)
C) informational density (e.g.the number of proteins encoded)
D) ability to replicate information (e.g.the ability to transfer genes to progeny)
E) structural diversity (e.g.the number of forms into which the molecule could fold)

Question 41

Crick said that "DNA is,at bottom,a much less sophisticated molecule than a highly evolved protein and for this reason reveals its secrets more easily." How is DNA less complex than protein?

Question 42

A region of DNA 100 bp in length has the potential to be represented by 4100 unique sequences.

Question 43

Accuracy of replication is enhanced by the redundancy of DNA,enzymatic repair of damaged DNA,and the remarkable precision of the cellular replication machinery.

Question 44

During the DNA replication process,RNA primers are removed and replaced with DNA.Briefly state why it is important that this RNA be replaced with DNA.

Question 45

When Meselson and Stahl performed the experiment that showed that replication is a semiconservative process,they utilized E.coli,and various isotopes of nitrogen (¹⁵N and ¹⁴N).Explain briefly what their results would have been if DNA replicated conservatively.

Question 46

Viruses may have RNA,ssDNA,or dsDNA as their molecule of heredity.Design an experiment that would allow you to test an unknown virus and determine which it carried.

Question 47

Human DNA is replicated in a conservative manner.

Question 48

Why are DNA molecules considered redundant?

Question 49

Viruses use only DNA as their genetic material.

Question 50

If DNA replication were conservative or dispersive (instead of semiconservative),what would be the results of the Meselson-Stahl experiment?

Question 51

How did Watson and Crick's scientific approach differ from that of other scientists who studied DNA?

Question 52

Briefly describe the role of an initiator protein in DNA replication.

Question 53

In DNA replication,new DNA is produced in a continuous bidirectional fashion.

Question 54

DNA has a highly negative charge throughout the molecule and therefore has no polarity.

Question 55

Griffith found that smooth (S)forms of S.pneumoniae have a polysaccharide capsule and rough (R)forms do not.Only S forms cause infection.Briefly describe how Griffith demonstrated transformation using live R form and heat-killed S form bacteria.