Deck 12: DNA Organization in Chromosomes

Question 1

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 ________.

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

Answer 1

C

Question 2

Describe the chromosomal conformations of φX174 and polyomaviruses.

Answer 2

single-stranded DNA, circular; double-stranded DNA, circular, respectively

Question 3

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

A) called heterochromatin and euchromatin
B) uniform in the genetic information they contain
C) separated by large stretches of repetitive DNA
D) each void of typical protein-coding sequences of DNA
E) void of introns

Answer 3

A

Question 4

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?

Question 5

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

Question 6

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) primers
C) alphoid families
D) euchromatic regions
E) telomere-associated sequences

Question 7

List the components of a nucleosome.

Question 8

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

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

Question 9

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.

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?

Question 11

In E. coli, the genetic material is composed of ________.

A) circular, double-stranded DNA
B) linear, double-stranded DNA
C) RNA and protein
D) circular, double-stranded RNA
E) polypeptide chains

Question 12

What similarities do bacterial chromosomes have with eukaryotic chromosomes?

Question 13

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

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

Question 14

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?

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

Question 15

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

Question 16

What are minisatellites and microsatellites?

Question 17

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

Question 18

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

Question 19

List several configurations that characterize different viral chromosomes.

Question 20

In instances in the eukaryotic genome, DNA sequences represent evolutionary vestiges of duplicated copies of genes. What are such regions called and what are their characteristics?

Question 21

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

Question 22

What is meant by SINE in terms of chromosome structure? By LINE? Why are they called "repetitive"?

Question 23

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

Question 24

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

Question 25

Briefly state what is meant by repetitive DNA.

Question 26

Each human contains an identical set of VNTRs.

Question 27

How do VNTRs relate to DNA fingerprinting?

Question 28

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

Question 29

In contrast with euchromatin, heterochromatin contains more genes and is earlier replicating.

Question 30

In situ hybridization allows one to "visualize" the location of labeled RNA or DNA in a tissue or cell.

Question 31

Telomerase is an enzyme involved in the replication of the ends of eukaryotic chromosomes.

Question 32

The E. coli chromosome is circular and double-stranded DNA.

Question 33

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?

Question 34

Viral genomes are always linear, double-stranded DNA.