Question

A ssRNA shows inverted tandem repeat. What would be its secondary structure?

(a) Linear

(b) Hair pin

(c) Stem-loop structure

(d) Crucifix

The question was asked in an interview for internship.

My doubt stems from Transcription in Prokaryotes : Termination in division Gene Expression : Transcription Prokaryotes of Cytogenetics

Answer 1

Correct option is (c) Stem-loop structure

To explain I would say: A tandem repeat has some bases between the palindrome regions resulting in the formation of the loop. The remaining complementary sequences of the palindrome forms the stem. In case of dsRNA similar sequence would form a crucifix while absence of intersecting sequence will form hairpin.