Question

which of the following difference between dna and rna allows them to perform their unique functions?
○ dna contains ribose, while rna contains deoxyribose.
○ dna is single - stranded, whereas rna is double - stranded.
○ dna contains thymine, while rna contains uracil.
○ rna is found only in the nucleus, while dna is found only in the cytoplasm.

Explanation:

• Analyze each option:
• Option 1: DNA has deoxyribose, RNA has ribose. So this is incorrect.
• Option 2: DNA is double - stranded, RNA is single - stranded. This is incorrect.
• Option 3: DNA contains thymine (T), RNA contains uracil (U) instead of thymine. This is a correct difference that affects their functions (e.g., DNA's stability for storage, RNA's flexibility for various roles like translation).
• Option 4: DNA is mainly in the nucleus, RNA is found in nucleus and cytoplasm (e.g., mRNA, tRNA, rRNA in cytoplasm for translation). So this is incorrect.

Answer:

C. DNA contains thymine, while RNA contains uracil.