Deck 12: DNA Organization in Chromosomes

Question 1

What similarities do bacterial chromosomes have with eukaryotic chromosomes?

Answer 1

Both have double-stranded DNA and several types of proteins associated with that DNA (nucleosomes in eukaryotes and HU and H1 proteins in bacteria).

Question 2

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

Answer 2

D

Question 3

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

Answer 3

A

Question 4

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

Question 5

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 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

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

Question 8

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 9

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

Question 10

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 11

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

Question 12

What are minisatellites and microsatellites?

Question 13

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

Question 14

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 15

Describe the chromosomal conformations of φX174 and polyomaviruses.

Question 16

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 17

List several configurations that characterize different viral chromosomes.

Question 18

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

Question 19

List the components of a nucleosome.

Question 20

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 21

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

Question 22

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

Question 23

Viral genomes are always linear,double-stranded DNA.

Question 24

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 25

Each human contains an identical set of VNTRs.

Question 26

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

Question 27

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

Question 28

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

Question 29

Briefly state what is meant by repetitive DNA.

Question 30

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

Question 31

How do VNTRs relate to DNA fingerprinting?

Question 32

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

Question 33

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

Question 34

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