NEETZoologyMolecular Basis of Inheritance
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The total length of DNA in a typical mammalian cell is approximately 2.2 meters. Reason (R): The mammalian genome contains 6.6 10^9 base pairs and the pitch of the B-DNA helix is 0.34 nm. In the light of the above statements, choose the correct answer from the options given below:
Options
- ABoth Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A)
- BBoth Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A)
- CAssertion (A) is true but Reason (R) is false
- DAssertion (A) is false but Reason (R) is true
Correct answer
C. Assertion (A) is true but Reason (R) is false
Step-by-step solution
Assertion (A) is true. The total length of DNA in a typical mammalian cell is calculated by multiplying the total number of base pairs ( 6.6 10^9 bp) by the distance between two consecutive base pairs ( 0.34 10⁻⁹ m), which gives approximately 2.2 meters. Reason (R) is false. While it is true that the diploid mammalian genome contains 6.6 10^9 base pairs, the pitch of the B-DNA helix is 3.4 nm, not 0.34 nm. The value 0.34 nm represents the distance between two consecutive base pairs, not the pitch. Answer: Assertion