dsRNA must

dsRNA must

• A. Be linear
• B. Pair to nucleotides so it can have equal amount of A/U and C/G
• C. Be resistant to RNases
• D. Be circular

Answer: (B)

The key idea is that a double-stranded molecule relies on specific base pairing. In RNA, adenine pairs with uracil and cytosine pairs with guanine. For the two strands to align correctly and form stable base pairs, every A on one strand must pair with a U on the other, and every C must pair with a G. That means the overall molecule must have equal numbers of A and U, and equal numbers of C and G. So dsRNA must pair to nucleotides in a way that enforces those equal counts. The other features listed—being linear or circular, or being resistant to RNases—are not required by the duplex structure and aren’t universal properties of dsRNA.

The key idea is that a double-stranded molecule relies on specific base pairing. In RNA, adenine pairs with uracil and cytosine pairs with guanine. For the two strands to align correctly and form stable base pairs, every A on one strand must pair with a U on the other, and every C must pair with a G. That means the overall molecule must have equal numbers of A and U, and equal numbers of C and G. So dsRNA must pair to nucleotides in a way that enforces those equal counts.

The other features listed—being linear or circular, or being resistant to RNases—are not required by the duplex structure and aren’t universal properties of dsRNA.