Chapter 12: DNA Structure, Replication, and Organization

Question 1

purines

Answer 1

• adenine, guanine

- double-ring structures

Question 2

pyrimidines

Answer 2

• thymine, cytosine

- single-ring structures

Question 3

Chargaff’s Rule

Answer 3

-AT/GC

Question 4

Which end is the phosphate group bonded?

Answer 4

5` end

Question 5

Which end is the hydroxyl ground bonded?

Answer 5

3` end

Question 6

Rosalind Franklin’s work suggested what DNA structure?

Answer 6

double helix

Question 7

DNA helicase

Answer 7

unwinds the double helix

Question 8

topoisomerase (gyrase)

Answer 8

prevents twisting as DNA unwinds

Question 9

single-stranded binding proteins

Answer 9

prevent separated strands from coming together again behind DNA helicase