Question 1

Chromosomal regions that represent evolutionary vestiges of duplicated copies of genes that have underdone sufficient mutations to render them untranscribable are called_________ .

Accepted Answer

A)  satellites
B)  alleles
C)  pseudogenes
D)  LINEs
E)  transposons C

Question 2

When native chromatin is digested with micrococcal nuclease,what significant result occurs?

Accepted Answer

DNA fragments of approximately 200 base pairs in length are formed.

Question 3

Chromatin of eukaryotes is organized into repeating interactions with protein octamers called nucleosomes.Nucleosomes are composed of which class of molecules?

Accepted Answer

A)  histones
B)  H1 histones
C)  glycoproteins
D)  lipids
E)  nonhistone chromosomal proteins A

Question 4

List the components of a nucleosome.

Accepted Answer

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Question 5

How was it experimentally determined that "puffs" are transcriptionally active?

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Question 6

This figure represents supercoiled,circular,double- stranded DNA:  If this molecule of DNA originated as a linear molecule with a linking number L of 30,which was then circular unwound,the L for the unwound circular molecule would be_________ .

Accepted Answer

A)  28
B)  30
C)  18
D)  20
E)  32

Question 7

What are histones,and how are they arranged in nucleosomes?

Accepted Answer

The answer of What are histones,and how are they arranged...

Question 8

In addition to highly repetitive and unique DNA sequences,a third category of DNA sequences exists.What is it called,and what types of elements are involved in it?

Accepted Answer

A)  multiple gene family DNA; hemoglobin and 5.0S RNA
B)  permissive DNA; centromeres and heterochromatin
C)  dominant DNA; euchromatin and heterochromatin
D)  composite DNA; telomeres and heterochromatin
E)  moderately repetitive DNA; SINEs,LINEs,and VNTRs

Question 9

What is the relationship between topoisomers?

Accepted Answer

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Question 10

A particular variant of the lambda bacteriophage has a DNA double- stranded genome of 51,365 base pairs.How long would this DNA be?

Accepted Answer

The answer of A particular variant of the lambda bacteriophage...

Question 11

Viral chromosomes exist in a variety of conformations and can be made up of _________

Accepted Answer

A)  RNA only
B)  DNA only
C)  protein- or lipid- coding sequences
D)  DNA or RNA
E)  DNA,RNA,or protein

Question 12

Although mutations have been observed in many different genes,they have not been isolated in histones.Why does this seem reasonable? If one wanted to produce antibodies to histones,would it be an easy task? Explain your answer.

Accepted Answer

The answer of Although mutations have been observed in many...

Question 13

The condition that some organisms contain much larger amounts of DNA than are apparently "needed" and that some relatively closely related organisms may have vastly different amounts of DNA is more typical in _________.

Accepted Answer

A)  eukaryotes than in prokaryotes
B)  RNA viruses than in DNA viruses
C)  the alphoid rather than the diploid family
D)  prokaryotes than in eukaryotes
E)  viruses than in bacteria

Question 14

Explain how linear DNA can be supercoiled.

Accepted Answer

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Question 15

Briefly describe the makeup of VNTRs variable number tandem repeats).

Accepted Answer

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Question 16

Describe the chromosomal conformations of ΠX174 and polyomaviruses.

Accepted Answer

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Question 17

How do VNTRs relate to DNA fingerprinting?

Accepted Answer

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Question 18

What is unusual about the amino acid composition of histones? How is the function of histones related to the amino acid composition? Of which histones are nucleosomes composed?

Accepted Answer

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Question 19

Describe the basic structure of a nucleosome.What is the role of histone H1?

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Question 20

Approximately how much of the mammalian genome is composed of repetitive DNA?

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Exam 12: DNA Organization in Chromosomes