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Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYMolecular Basis of Inheritance1 Mark
MCQ
For question, two statements are given$-$one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes $(a), (b), (c)$ and $(d)$ as given below. Assertion: Sequences of bases in one polynucleotide chain of $\text{DNA}$ can determine the sequence of bases in the other chain.
Reason: In a $\text{DNA}$, amount of adenine equals that of thymine and amount of guanine equals that of cytosine, i.e., $A = T$ and $C = G$.
  • A
    Both assertion and reason are true, and reason is the correct explanation of assertion.
  • ✓
    Both assertion and reason are true, but reason is not the correct explanation of assertion.
  • C
    Assertion is true, but reason is false.
  • D
    Both assertion and reason are false.
✓

Answer

Correct option: B.
Both assertion and reason are true, but reason is not the correct explanation of assertion.
Although $A = T$ and $C = G,$ there is no any restriction or sequence of bases in one polynucleotide chain. Since $A$ is always linked to $T$ and $C$ to $G$ as determined from the above evidences, sequence of bases in one of polynucleotide should determine the sequence of bases in the other polynucleotide of the double helix.

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