Question

Consider the following and choose the correct answer Assertion [A]: DNA replication is semiconservative in nature. Reason [R]: Each daughter DNA molecule contains one parental strand and one newly synthesized strand. The correct answer is

• A. Both [A] and [R] are true and [R] is the correct explanation of [A]
• B. Both [A] and [R] are true and [R] is not the correct explanation of [A]
• C. [A] is true, but [R] is false
• D. [A] is false, but [R] is true

Hint:

Semiconservative replication was experimentally demonstrated by \[ \boxed{\text{Meselson and Stahl (1958).}} \] Each daughter DNA molecule consists of \[ \boxed{ 1\ \text{old strand} + 1\ \text{new strand}. } \]

Answer 1

The Correct Option is A

Step 1: Examine the assertion. DNA replication is said to be semiconservative because each newly formed DNA molecule conserves one of the original parental strands. Hence, \[ \boxed{\text{Assertion [A] is true}.} \]

Step 2: Examine the reason. After DNA replication, each daughter DNA molecule contains \[ \boxed{ \text{one parental strand and one newly synthesized strand.} } \] Thus, \[ \boxed{\text{Reason [R] is true}.} \]

Step 3: Establish the relationship. The reason correctly explains why DNA replication is termed semiconservative. Therefore, \[ \boxed{ \text{Both [A] and [R] are true and [R] correctly explains [A].} } \] Thus, \[ \boxed{(A)} \] is the correct answer.