codons and anticodons??

Question

Ok this was on my microbiology test and I got the answer wrong....the thing is....I don't understand why. Can you help me??

Choose the sequence of the codon corresponding to the anticodon C U G. Standard conventions are followed in listing all the sequences in this question.

A. CUG
B. GUC
C. GTC
D. GAC
E. CAG

The correct answer is E. CAG, but I thought it was D. GAC. Can someone tell me why it's CAG? Thanks so much for your help!!

Answer 1

By "standard conventions", they mean that the sequence is written in its 5' to 3' direction.

So, the colon is 5' CUG 3'. In order to base pair with this, the anticodon would have to be 3'GAC5', and when you write it in "standard convention" order, you have 5'CAG3'.

Hope this helps...