Question

Shown below is DNA sequence on the coding strand for a structural gene.

5'-AGGACTAAATGACATGGACACTAACTAGTTGGAAGCTAACCC... -3'

How many amino acids does the polypeptide encoded by this sequence contain?

A. 7

B. 8

C. 6

D. 12

E. 10

Answer 1

ANSWER :

If the base sequence of DNA on its coding strand is :-

5' AGGACTAAATGACATGGACACTAACTAGTTGGAAGCTAACCC 3'

then, the corresponding mRNA nucleotide sequence would be :-

5' AGG ACU AAA UGA CAU GGA CAC UAA CUA GUU GGA AGC UAA CCC 3'

Since, each codon of m-RNA that codes for a specific amino acid contains three sequence of nitrogenous base, except three terminal codons that would stop the translation process to proceed further. The UGA is a stop codon which located at the fourth position in the m-RNA sequence. Hence only first 3 amino acids would be produce during the translation.

answered by: anonymous