Why Okazaki fragments are created during DNA replication A B

Why Okazaki fragments are created during DNA replication?

A. Because DNA helicase cannot unwind DNA double helix from 5’ end

B. Because DNA helicase cannot unwind DNA double helix from 3’ end

C. Because DNA polymerase cannot synthesize new DNA chain from 5’ end

D. Because DNA polymerase cannot synthesize new DNA chain from 3’ end

Explain

Solution

DNA replication takes place by DNA polymerase enzyme that synthesises DNA strand or adds nucleotides in 5\'--->3\' direction. During DNA replication, both the strands gets copied resulting in -- leading strand which is synthesised continuously in 5\' ---> 3\' direction and the other lagging strand synthesised discontinuously as DNA polymerase cannot synthesize in 3\'--->5\' direction, so once the 1000ntds are added in the leading strand, the lagging strand synthesis can take place.

So answer is (C).