CBSE 2024 · Region 5 · Set 2 · Q14 · 1 mark
Assertion (A): The sugar-phosphate backbone of two chains in DNA double helix show anti-parallel polarity.
Reason (R) : The phosphor-diester bonds in one strand go from a $\displaystyle 3$' carbon of one nucleotide to a $\displaystyle 5$' carbon of adjacent nucleotide, whereas those in complementary strand go vice versa.
Official answer
From CBSE’s own marking scheme for this paper.
(A)
Both (A) and (R) are true and (R) is the correct explanation of (A).
Molecular Basis of InheritanceThe DNAUnderstandassertion_reasonmedium
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CBSE Class 12 Biology past-paper question from the 2024board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.