Question

DNA synthesis during replication is

• A. Discontinuous
• B. Continuous
• C. Semi-discontinuous
• D. None of the above

Answer 1

The correct option is C Semi-discontinuous

One of the template DNA strands is oriented 3' to 5' at the replication fork, and it can be copied continuously by a DNA polymerase extending the new DNA chain in a 5’ to 3’ direction, This new DNA chain is called the leading strand. However, the DNA polymerase cannot synthesize DNA in 5’ to 3’ direction. Since the other template strand is oriented in 5’ to 3’ the second strand is synthesized in a discontinuous fashion and this strand is called the lagging strand. Thus, one strand is synthesized continuously and the other discontinuously so it is semi-discontinuous synthesis. Thus, the correct option is C