Question 1

In DNA,most satellite sequences are found in

Accepted Answer

A)  chromosome arms. 
B)  telomeres. 
C)  centromeres. 
D)  spaces around the dark bands. 
E)  None of the choices are correct.

Question 2

The two chromatids of each replicated chromosome must separate from one another and segregate during

Accepted Answer

A)  mitosis. 
B)  meiosis I. 
C)  meiosis II. 
D)  both mitosis and meiosis I. 
E)  both mitosis and meiosis II.

Question 3

Cohesins are a multisubunit protein complex that functions to

Accepted Answer

A)  hold sister chromatids together. 
B)  ensure that proper chromosome arm length is maintained. 
C)  allow easy karyotyping. 
D)  develop meiotic chromosome replication. 
E)  All of the choices are correct.

Question 4

During development,an XX female embryo will form one of the X chromosomes in each cell into a Barr body.This usually occurs

Accepted Answer

A)  about two weeks after zygote formation. 
B)  by the end of the first trimester. 
C)  at the 16-cell stage. 
D)  in the X that is the most recessive. 
E)  in the X that is the least recessive.

Question 5

Telomerase is an enzyme that consists of a protein portion in association with RNA.

Accepted Answer

A) True 
 B)False

Question 6

Which of these is required for first strand invasion in the double-strand break repair model?

Accepted Answer

A)  blunt end double strand break on two sister chromatids 
B)  3' single strand tails on one sister chromatid 
C)  3' single strand tails on both sister chromatids 
D)  5' single strand tails on one sister chromatid 
E)  5' single strand tails on both sister chromatids

Question 7

Nucleosomal chromatin,with a diameter of 100Å,supercoils into a 300Å superhelix.The histone that appears to be responsible for this compaction is

Accepted Answer

A)  H4. 
B)  H3. 
C)  H2. 
D)  H1. 
E)  H0.

Question 8

Chromosomes are composed of chromatin.

Accepted Answer

A) True 
 B)False

Question 9

The linear chromosomes of eukaryotic cells terminate at both ends in protective caps called telomeres.

Accepted Answer

A) True 
 B)False

Question 10

That histones have changed so little throughout evolution underscores the importance of their contribution to chromatin structure.

Accepted Answer

A) True 
 B)False

Question 11

The first level of compaction of DNA consists of

Accepted Answer

A)  DNA winding around histones to form small nucleosomes. 
B)  tight coiling of DNA with nucleosomes into higher order structures. 
C)  high level compaction into metaphase-type chromosomes. 
D)  histone,DNA,and nonhistone covalent bonding. 
E)  DNA double helix unwinding.

Question 12

Discuss how a nucleosome is constructed from DNA and histone proteins.

Accepted Answer

The answer of Discuss how a nucleosome is constructed from...

Question 13

Which of the following statements about a heteroduplex is not true?

Accepted Answer

A)  Heteroduplex formation can be initiated by a double-strand break. 
B)  A heteroduplex can contain mispaired C-T basepairs. 
C)  The length of a heteroduplex is increased by branch migration. 
D)  A heteroduplex can contain mispaired G-T basepairs. 
E)  Heteroduplexes always results in crossovers.

Question 14

In higher eukaryotes,kinetochores attach to

Accepted Answer

A)  one spindle fibre. 
B)  one spindle fibre on each side. 
C)  multiple spindle fibres. 
D)  multiple repeating structural subunits. 
E)  telomeres.

Question 15

Describe the ways in which telomeres are critical to chromosome function.

Accepted Answer

The answer of Describe the ways in which telomeres are...

Question 16

In mammalian cells,replication proceeds

Accepted Answer

A)  unidirectionally. 
B)  bidirectionally. 
C)  unidirectionally from many origins. 
D)  bidirectionally from only one origin. 
E)  polydirectionally.

Question 17

Which of the following statements about Holliday junctions is false?

Accepted Answer

A)  Resolution of a Holliday junction may produce a heteroduplex and a crossover. 
B)  Resolution of a Holliday junction may produce a heteroduplex without a crossover. 
C)  There are two Holliday junctions involved in meiotic recombination. 
D)  Resolution of a Holliday junction may produce a crossover without a heteroduplex. 
E)  Resolution of a Holliday junction involves cutting one strand of two different DNA double helices.

Question 18

The nicking of DNA that initiates recombination during mitosis may be due to all but

Accepted Answer

A)  instruction from normal cell-cycle program. 
B)  X-rays. 
C)  chemical damage. 
D)  physical damage. 
E)  radiation.

Question 19

Which of the following is not a piece of evidence that supports the radial loop-scaffold model of DNA packaging?

Accepted Answer

A)  Histone-depleted metaphase chromosomes still maintain their X-like shapes. 
B)  Electron micrographs of whole-mounted mitotic chromosomes show loops of chromatin at the periphery of the chromosomes. 
C)  Topoisomerase II assists in 100Å packaging. 
D)  Special,irregularly spaced repetitive base sequences associate with nonhistone proteins to define the chromatin loops. 
E)  All of the choices are such evidence.

Question 20

During metaphase of mitosis the chromosomes look like a tangled mass of grainy string scattered throughout the nucleus.

Accepted Answer

A) True 
 B)False

Exam 5: Dna Structure, Replication, and Recombination

In DNA,most satellite sequences are found in

The two chromatids of each replicated chromosome must separate from one another and segregate during

Cohesins are a multisubunit protein complex that functions to

During development,an XX female embryo will form one of the X chromosomes in each cell into a Barr body.This usually occurs

Telomerase is an enzyme that consists of a protein portion in association with RNA.

Which of these is required for first strand invasion in the double-strand break repair model?

Nucleosomal chromatin,with a diameter of 100Å,supercoils into a 300Å superhelix.The histone that appears to be responsible for this compaction is

Chromosomes are composed of chromatin.

The linear chromosomes of eukaryotic cells terminate at both ends in protective caps called telomeres.

That histones have changed so little throughout evolution underscores the importance of their contribution to chromatin structure.

The first level of compaction of DNA consists of

Discuss how a nucleosome is constructed from DNA and histone proteins.

Which of the following statements about a heteroduplex is not true?

In higher eukaryotes,kinetochores attach to

Describe the ways in which telomeres are critical to chromosome function.

In mammalian cells,replication proceeds

Which of the following statements about Holliday junctions is false?

The nicking of DNA that initiates recombination during mitosis may be due to all but

Which of the following is not a piece of evidence that supports the radial loop-scaffold model of DNA packaging?

During metaphase of mitosis the chromosomes look like a tangled mass of grainy string scattered throughout the nucleus.