Question

The direction in which new strand is synthesized during the process of replication is

• A. 3’ $\to$ 5’
• B. 5’ $\to$ 3’
• C. Both a and b
• D. None of the above

Answer 1

The correct option is B 5’ $\to$ 3’

The characteristic feature of the enzyme catalyzing the polymerisation reaction, DNA polymerase, is that it can synthesize strands only in 5’ $\to$ 3’ direction. Hence, the dNTPs get added to the free 3’ OH end in a complementary newly synthesized daughter strand. Consequently, the strand synthesis proceeds in 5’ $\to$ 3’ direction in both leading and lagging strands.