Question

Which of the mRNA sequences would be translated in a test tube as the three different polypeptide chains polyserine, polyglutamine, and polyvaline, assuming that laboratory conditions were such that translation could start anywhere along the mRNA molecule?

	1. 5'–ACUGACUGACUG….–3'
	2. 5'–GUCAGUCAGUCA….–3'
	3. 5'–AUCGAUCGAUCG….–3'
	4. 5'–GCUAGCUAGCUA….–3'
	5. None of the other answer options is correct.

Answer 1

break the nucleotide sequence given in the options into 3 letter codon-

on the breaking of the first sequence- ACU GAC UGA. since UGA is a stop codon the synthesis will get terminated.

on breaking of the 2nd sequence- GUC AGU CAG UCA GUC AGU CAG UCA..... GUC codes for valine, AGU codes for serine and CAG codes for glutamine and the same 3 letters codon will get repeated again and again (look the sequence) which will code for the same kind of amino acids again and again. hence option 2 ( 5'---GUCAGUCAGUCA....3') is correct.