Question

Regarding the assertion and reason, select the correct option.

Assertion $\left[A\right]$: DNA replication is semiconservative in nature.

Reason \left [ R \right ]: One of the DNA strands is synthesised continuously, while the other is synthesised discontinuously.

• A. Both A and R are true and R explains A
• B. Both A and B are true, but R does not explain A
• C. A is true and R is false
• D. Both A and R are false

Answer 1

The correct option is B

Both A and B are true, but R does not explain A

DNA replication is described as “semiconservative” because in each of the newly formed daughter DNA helices, one of the parental DNA strands (the one which served as template during replication) gets passed on as such, while the other strand is apparently, complementary to this. Thus, one half of the parental DNA can be said to be “conserved”, giving replication the adjective “semiconservative”. DNA replication is also “semi-discontinuous” in that one of the strands (the leading strand) is synthesised continuously, while the other strand is synthesised discontinuously by the formation of Okazaki fragments.