RNA and DNA molecules can form doublestranded structures just as in the case of DNADNA duplexes. Given this fact, hybridization of a DNA strand (5′-ACGTC-3′) with which of the following RNA molecules will result in the most stable RNA-DNA duplex?
A) 5′-AGUAC-3′
B) 5′-CAUGA-3′
C) 5′-GACGU-3′
D) 5′-GGCAG-3′
E) 5′-UGCAG-3′

Question

Quizplus · Accepted Answer

The RNA molecule 5′-GACGU-3′ is complementary to the DNA strand 5′-ACGTC-3′, forming stable Watson-Crick base pairs (A-U, C-G, G-C, T-A, C-G).  DND-DNA and RNA-DNA duplexes can form due to base paring between complimentary nucleotides. In the case of RNA-DNA duplexes, the U in an RNA molecule forms a base-pair with A in a DNA molecule. In addition, duplexes are formed with antiparallel orientation. Thus, the only RNA that can form a stable 1:1 duplex with the target DNA must have the antiparallel complimentary sequence.

RNA and DNA Molecules Can Form Doublestranded Structures Just as in the Case