Question

Antonio is creating a presentation for research on transcription using a DNA strand sample and 3-D RNA models. In order to better explain the complexities of RNA structure and base composition, he creates a model with four RNA complements. Which of these models does not abide according to what is known about RNA and base pairing?

5'-GGGCCTATTAACCAGG-3'

a. 3'-CCCGGAUAAUUGGUCC-5'
b. 5'-UCUGGUUAAUAGGUUU-3'
c. 5'-CCUGGUUAAUAGGCCC-3'
d. 5'-CCUAACCAAUAGGCCC-3

Answer 1

The model that does not follow the rules of RNA base pairing is option b: 5'-UCUGGUUAAUAGGUUU-3', as it does not properly align with the given DNA strand 5'-GGGCCTATTAACCAGG-3'. Only option a provides the correct RNA complements and orientation.

Step-by-step explanation:

RNA base pairing:

The correct answer to which RNA model does not abide by the known rules of base pairing is option b: 5'-UCUGGUUAAUAGGUUU-3'. It is the incorrect model because it does not properly complement the DNA strand presented, 5'-GGGCCTATTAACCAGG-3'. In RNA, adenine (A) pairs with uracil (U), and cytosine (C) pairs with guanine (G). The DNA template strand is 5'-GGGCCTATTAACCAGG-3', so the correct RNA complement must be 3'-CCCGGAUAAUUGGUCC-5', which matches option a.

The other RNA models are either not complementary (option b) or not oriented correctly relative to the DNA strand's direction (options c and d). Option a is the only sequence that shows complementarity while also maintaining the anti-parallel orientation required in the transcription process.