Comprehension Questions

Section 11.1

Question 11.1

How does supercoiling arise? What is the difference between positive and negative supercoiling?

Question 11.2

What functions does supercoiling serve for the cell?

Question 11.3

Describe the composition and structure of the nucleosome.

Question 11.4

Describe in steps how the double helix of DNA, which is 2 nm in width, gives rise to a chromosome that is 700 nm in width.

Question 11.5

What are polytene chromosomes and chromosomal puffs?

Question 11.6

What are epigenetic changes and how are they brought about?

Section 11.2

Question 11.7

Describe the function of the centromere. How are centromeres different from other regions of the chromosome?

Question 11.8

Describe the function and molecular structure of a telomere.

Question 11.9

What is the difference between euchromatin and heterochromatin?

Section 11.3

Question 11.10

What is the C value of an organism?

Question 11.11

Describe the different classes of DNA sequence variation that exist in eukaryotes.

Section 11.4

Question 11.12

Explain why many traits encoded by mtDNA and cpDNA exhibit considerable variation in their expression, even among members of the same family.

Question 11.13

What is the endosymbiotic theory? How does it help to explain some of the characteristics of mitochondria and chloroplasts?

Question 11.14

What evidence supports the endosymbiotic theory?

Question 11.15

Briefly describe the organization of genes on the chloroplast genome.

Question 11.16

What is meant by the term “promiscuous DNA”?

For more questions that test your comprehension of the key chapter concepts, go to for this chapter.