NEET Botany DNA Structure MCQ Question
Which of the following combinations about DNA structure is correct?
DNA has a double helix structure with a consistent distance between base pairs, formed by sugar and phosphate backbone.
RNA contains thymine instead of uracil and has a double-stranded structure.
Exons are sequences that do not appear in mature RNA, while introns are expressed sequences.
The 5'-end of a polynucleotide chain has a free OH group, while the 3'-end has a phosphate group.
Correct Answer
Detailed Explanation
Option A correctly describes the double helix structure of DNA and its consistent distance between base pairs due to the sugar-phosphate backbone. Option B incorrectly states that RNA contains thymine instead of uracil. Option C misidentifies the roles of exons and introns. Option D reverses the roles of the 5'-end and 3'-end of the polynucleotide chain.
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