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Question: Answered & Verified by Expert
If $A$ and $C$ make $30 \%$ and $20 \%$ of DNA, respectively, what will be the percentage composition of $\mathrm{T}$ and $\mathrm{G}$ ?
BiologyMolecular Basis of InheritanceNEETNEET 2022 (Phase 2)
Options:
  • A $\mathrm{T}: 20 \%, \mathrm{G}: 30 \%$
  • B $\mathrm{T}: 30 \%, \mathrm{G}: 20 \%$
  • C $\mathrm{T}: 30 \%, \mathrm{G}: 30 \%$
  • D $\mathrm{T}: 20 \%, \mathrm{G}: 20 \%$
Solution:
1652 Upvotes Verified Answer
The correct answer is: $\mathrm{T}: 30 \%, \mathrm{G}: 20 \%$
$$
\begin{aligned}
& \mathrm{A} \rightarrow 30 \%=\mathrm{T} \rightarrow 30 \% \\
& \mathrm{C} \rightarrow 20 \%=\mathrm{G} \rightarrow 20 \%
\end{aligned}
$$
According to chargaff's rule, Adenine (A) pairs with Thymine (T) and Cytosine (C) pairs with Guanine (G). So, The ds DNA have equal percentage of $A$ and $T$ or $G$ and $C$.

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