A: The DNA molecule consists of two polynucle | vedclass

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Question

(B) Assertion $(A)$ is true because $DNA$ is a double-stranded helix where the two polynucleotide chains run in opposite directions ($5' \rightarrow 3

Vedclass · Accepted Answer

$A$ and $R$ are both true,but $R$ is not the correct explanation of $A$.

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(B) Assertion $(A)$ is true because $DNA$ is a double-stranded helix where the two polynucleotide chains run in opposite directions ($5' \rightarrow 3'$ and $3' \rightarrow 5'$),which is known as an antiparallel orientation.Reason $(R)$ is also true as the double-helix model of $DNA$ was indeed proposed by James $Watson$ and Francis $Crick$ in $1953$.However,the fact that $Watson$ and $Crick$ proposed the model is a historical fact and does not explain why the chains are antiparallel (which is due to the chemical structure of the deoxyribose sugar and the phosphate backbone). Therefore,$R$ is not the correct explanation of $A$.

$A$: The $DNA$ molecule consists of two polynucleotide chains that run antiparallel to each other.
$R$: The $DNA$ molecular model was proposed by scientists $Watson$ and $Crick$.

Similar Questions

Which of the following is correct for calculating the total length of $DNA$?

In the $DNA$ molecule,

Identify the pair of nucleotides in $DNA$ that are linked by three hydrogen bonds.

Assertion $(A) :$ The distance between two polynucleotide chains in $\text{dsDNA}$ remains constant.
Reason $(R) :$ Always a purine comes opposite to pyrimidine or vice versa.

The acidity of the $DNA$ molecule is due to:

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$A$: The $DNA$ molecule consists of two polynucleotide chains that run antiparallel to each other.$R$: The $DNA$ molecular model was proposed by scientists $Watson$ and $Crick$.