The elongation of the lagging strand during DNA synthesis（）
A. In the 3’ to 5’ direction
B. Produces Okazaki fragments
C. Polymerizes in the direction of fork movement
Does not require a template strand
Functions of DNA polymerases and accessory proteins in eukaryotic DNA replication include（）
A. PCNA protein, a sliding clamp unit for DNA
B. DNA polymerase α, initiation the synthesis of new strands
C. RPA protein, and equivalent of SSB proteins in bacteria
D. All of the above
What is the function of DNA topoisomerases（）
A. Cleaving nucleotides from the ends of DNA
B. Adding or removing supercoils
C. Methylation of the nitrogenous bases
D. Methylation of the nitrogenous bases
Several enzymes are needed in nucleotide excision repair, they are（）
A. Several enzymes are needed in nucleotide excision repair, they are
B. glycosylase, exonuclease, DNA polymerase and ligase
C. MutS, MutL, MutH, DNA polymerase and ligase
D. endonuclease, exonuclease, DNA polymerase and ligase
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