Topic 24.1: The DNA — Important NEET MCQs & Solutions
💡 Quick Formula Callout: Chargaff's Rule
For double-stranded DNA, the amount of Adenine equals Thymine (%A = %T), and Guanine equals Cytosine (%G = %C).
Therefore, total Purines = total Pyrimidines: A + G = T + C or (A+G)/(T+C) = 1.
NCERT Line-by-Line Practice Questions
Test your understanding with these high-yield, NCERT-aligned multiple-choice questions. Click "Submit" to see your score and detailed step-by-step explanations for every question to solidify your concepts.
Previous Year Questions (PYQs) on DNA Structure
Explanation: The phosphate group is linked to the 5' carbon of the pentose sugar via a phosphoester bond, forming the backbone of the polynucleotide chain.
Frequently Asked Questions (FAQs)
A: DNA is chemically and structurally more stable. The absence of the 2'-OH group in deoxyribose sugar makes DNA less reactive and less prone to hydrolysis and mutations compared to RNA.
A: A DNA strand has directionality (polarity). One end has a free phosphate group at the 5' carbon (5' end), and the other end has a free hydroxyl group at the 3' carbon (3' end).
