Exam 12: DNA Organization in Chromosomes

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

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

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?

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?

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

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

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 ________.

Briefly state what is meant by repetitive DNA.

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.

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

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?

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

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

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

List several configurations that characterize different viral chromosomes.

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 ________.

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

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

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

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