DNA replication

Question 1

DNA polymerase

Answer 1

add dNTPs to free 3’-OH of base-paired nucleotide to synthesis a complementary strand

Question 2

DNA polymerase III (of E. coli)

Answer 2

5’-3’ polymerase activity. 3’-5’ exonuclease activity.

Question 3

DNA polymerase I (of E. coli)

Answer 3

5’-3’ polymerase activity. 5’-3’ exonuclease activity. 3’-5’ exonuclease activity.

Question 4

Role of ssDNA binding proteins

Answer 4

keep strands apart, align strands, prevent formation of secondary structure, stimulate polymerases, interact with other replication proteins at replication forks

Question 5

linking number

Answer 5

number of times DNA strands cross each other

Question 6

primosome

Answer 6

DNA helicase + DNA primase

Question 7

DNA replication problem: preventing reannealing

Answer 7

Solution: single-stranded binding proteins

Question 8

DNA replication problem: unwinding the DNA douple helix

Answer 8

Solution: DNA helicase

Question 9

DNA replication problem: relieving tension from supercoiling

Answer 9

Solution: topoisomerases

Question 10

DNA replication problem: initiating DNA synthesis

Answer 10

Solution: DNA primase

Question 11

DNA polymerase I (of E. coli) - Klenow fragment.

Answer 11

68kDa. Responsible for 5’-3’ polymerase activity & 3’-5’ exonuclease activity.