Question 1

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

Histones contain large amounts of positively charged amino acids such as lysine and arginine. Thus, they can bind electrostatically to the negatively charged
phosphate groups of nucleotides. Nucleosomes are composed of all histones except H1.

Question 2

List the components of a nucleosome.

Accepted Answer

Histones H2A, H2B, H3, and H4 exist as two types of tetramers: (H2A)2 +
(H2B)2 and (H3)2 + (H4)2.

Question 3

In the formation of nucleosomes, one histone class, H1, is not directly involved, yet it does associate with DNA to form higher -level chromosomal structures. Where does this histone (H1) associate?

Accepted Answer

in the spaces between nucleosome/DNA complexes

Question 4

How does a polytene chromosome differ from a typical eukaryotic chromosome?

Accepted Answer

The answer of How does a polytene chromosome differ from...

Question 5

Chromatin of eukaryotes is organized into repeating interactions with protein octomers called nucleosomes. Nucleosomes are composed of which class of molecules?
A) lipids
B) nonhistone chromosomal proteins
C) H1 histones
D) glycoproteins
E) histones

Accepted Answer

Nucleosomes are composed of histone proteins, which form an octamer around which DNA is wrapped.

Question 6

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

Accepted Answer

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

Question 7

Compare and contrast the chromosome structure of viruses, bacteria, and eukaryotes.

Accepted Answer

The answer of Compare and contrast the chromosome structure of...

Question 8

What similarities do bacterial chromosomes have with eukaryotic chromosomes?

Accepted Answer

The answer of What similarities do bacterial chromosomes have with...

Question 9

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 10

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 11

List several configurations that characterize different viral chromosomes.

Accepted Answer

The answer of List several configurations that characterize different viral...

Question 12

That some organisms contain much larger amounts of DNA than are apparently "needed" and that other relatively closely related organisms may have vastly different amounts of DNA is more typical in _.
A) the alphoid rather than the diphloid family
B) prokaryotes than in eukaryotes
C) RNA viruses than in DNA viruses
D) viruses than in bacteria
E) eukaryotes than in prokaryotes

Accepted Answer

Eukaryotes often have large amounts of non-coding DNA, leading to variations in DNA content among closely related species, unlike prokaryotes which have more streamlined genomes.

Question 13

In E. coli, the genetic material is composed of
A) circular, double -stranded RNA
B) linear, double -stranded DNA
C) RNA and protein
D) circular, double -stranded DNA
E) polypeptide chains

Accepted Answer

E. coli, like most bacteria, has its genetic material in the form of a circular, double-stranded DNA molecule.

Question 14

Viral chromosomes exist in a variety of conformations and can be made up of _.
A) DNA, RNA, or protein
B) protein - or lipid -coding sequences
C) DNA or RNA
D) DNA only
E) RNA only

Accepted Answer

Viral chromosomes can be made up of DNA or RNA.

Question 15

Eukaryotic chromosomes contain two general domains that relate to the degree of
Condensation. These two regions are _.
A) called heterochromatin and euchromatin
B) each void of typical protein -coding sequences of DNA
C) separated by large stretches of repetitive DNA
D) void of introns
E) uniform in the genetic information they contain

Accepted Answer

Eukaryotic chromosomes have two regions: heterochromatin, which is tightly packed and less transcriptionally active, and euchromatin, which is loosely packed and more transcriptionally active.

Question 16

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

Accepted Answer

The answer of Describe the basic structure of a nucleosome....

Question 17

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

Accepted Answer

The answer of When native chromatin is digested with micrococcal...

Question 18

In addition to highly repetitive and unique DNA sequences, a third category of DNA sequences exists. What is it called, and which types of elements are involved in it?
A) composite DNA; telomeres and heterochromatin
B) multiple gene family DNA; hemoglobin and 5.0S RNA
C) dominant DNA; euchromatin and heterochromatin
D) moderately repetitive DNA; SINEs, LINEs, and VNTRs
E) permissive DNA; centromeres and heterochromatin

Accepted Answer

Moderately repetitive DNA includes sequences such as SINEs (Short Interspersed Nuclear Elements), LINEs (Long Interspersed Nuclear Elements), and VNTRs (Variable Number Tandem Repeats). These elements are repeated multiple times in the genome but not as extensively as highly repetitive sequences.

Question 19

In human chromosomes, satellite DNA sequences of about 170 base pairs in length are present in tandem arrays of up to 1 million base pairs. Found mainly in centromere regions, these DNA sequences are called _.
A) telomeres
B) euchromatic regions
C) primers
D) alphoid families
E) telomere -associated sequences

Accepted Answer

Alphoid families are satellite DNA sequences found in the centromere regions of human chromosomes, characterized by their tandem arrays and specific length.

Question 20

Describe the chromosomal conformations of $X174 and polyoma viruses.

Accepted Answer

The answer of Describe the chromosomal conformations of $X174 and...

Quiz 11: Chromosome Structure and Dna Sequence Organization

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?

List the components of a nucleosome.

In the formation of nucleosomes, one histone class, H1, is not directly involved, yet it does associate with DNA to form higher -level chromosomal structures. Where does this histone (H1) associate?

How does a polytene chromosome differ from a typical eukaryotic chromosome?

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

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

Compare and contrast the chromosome structure of viruses, bacteria, and eukaryotes.

What similarities do bacterial chromosomes have with eukaryotic chromosomes?

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

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.

List several configurations that characterize different viral chromosomes.

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

In E. coli, the genetic material is composed of

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

Eukaryotic chromosomes contain two general domains that relate to the degree of Condensation. These two regions are _.

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

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

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

In human chromosomes, satellite DNA sequences of about 170 base pairs in length are present in tandem arrays of up to 1 million base pairs. Found mainly in centromere regions, these DNA sequences are called _.

Describe the chromosomal conformations of $X174 and polyoma viruses.