31. Proteins involved in opening a replication bubble are

A. DNA helicases
B. single stranded binding proteins
C. ligase
D. DNA topoisomerase

32. What is the main damaging effect of UV radiation on DNA?

A. Depurination
B. Formation of thymine dimers
C. Single strand break
D. Dehydration

33. The higher order structure of DNA shows symmetry, whereas the higher order structures of most proteins do not. Why isn’t protein shape more regular like DNA?

A. DNA has one main function in cells whereas proteins have many.
B. The many different amino acid R groups on proteins confer many different shapes.
C. Some S amino acids cause proteins to bend; others cause protein to flatten.
D. All of the above

34. DNA helicase is used to

A. unwind the double helix
B. interact the double helix closely
C. break a phosphodiester bond in DNA strand
D. none of the above

35. Klenow fragment without free nucleotides exhibits

A. exonuclease activity
B. endonuclease activity
C. nickase activity
D. no activity