Question

The codon for anticodon 3'-UUUA-5' is

• A. 3'-AAU-5'
• B. 5'-UAAA-3'
• C. 5'-AAAU-3'
• D. 3'-UAAU-5'

Answer 1

Answer: (C)

5'-AAAU-3'

Uracil (U) always pairs with adenine (A). Further, the mRNA codon is read in 5’ to 3’ direction. Alignment of the mRNA and tRNA is antiparallel, which means that 5’ end of mRNA pairs with 3’ end of tRNA. This makes options A and D incorrect. The first base of the codon in mRNA (read in the 5’ to 3’direction) pairs with the third base of the anticodon, thus the anticodon 3'-UUUA-5' would pair with 5'-AAAU-3'codon. Thus option C is correct.