Step I Codon/anticodon question

[Sir Gillies]

Hi guys,

I came across a question on USMLE Rx that despite the explanation I don't understand.

tRNA anticodon is 5'-AGG, which codes for the amino acid arginine. Which nucleotide sequence is the corresponding codon for this tRNA?

The answer is 5'-CCU... but I though it was 5'-UCC

I hope someone brainier than me can explain it to me.
Thanks a lot in advance.

 

[Phloston]

mRNA and tRNA are always anti-parallel.

So 5' --> 3' mRNA = 3' --> 5' tRNA.

If the tRNA 5' --> 3' is AGG, you know the 5' --> 3' mRNA has to be CCU.

 

[image187]

mRNA and tRNA are always anti-parallel.

So 5' --> 3' mRNA = 3' --> 5' tRNA.

If the tRNA 5' --> 3' is AGG, you know the 5' --> 3' mRNA has to be CCU.

I second this man's answer

 

[withrye]

5'-agg-3'
3'-ucc-5'

So reading from the 5' end, it's CCU