8. Please describe the steps (the required enzymes in detail) of eukaryotic base excision repair (including two major subpathways). 

(e) Replisome

(d) Replicon;

20. Which of the following is NOT true concerning immunoglobulin gene recombination signal sequences? (A) There are conserved heptamers. (B) There are conserved nonamers. (C) Recombination occurs between a 12 bp signal and a 23 bp signal. (D) Recombination only occurs between two heptamers. (E) The conserved sequences are separated by a nonconserved sequence of either a 12 bp or a 23 bp sequence.

19. Primer extension is used to _____ (A) locate the binding of RNA polymerase (B) determine the interaction of RNA and proteins (C) determine the transcriptional start site (D) generate primers for PCR (E) none of the above

18. Put the following steps of E. coli primosome assembly in the correct order.

(1) DnaG binds.

(2) DnaA binds to oriC at dnaA boxes.

(3) DnaB binds to the open complex.

(4) DnaA, ATP, and HU protein melt the DNA. (A) 4, 1, 2, 3 (B) 3, 4, 1, 2 (C) 4, 2, 1, 3 (D) 2, 4, 3, 1 (E) 2, 4, 1, 3