A gene makes a polypeptide 7 amino acids long containing an

A gene makes a polypeptide 7 amino acids long containing an alternating sequence of phenyalanine and tyrosine. Assuming Phe = UUU, and Tyr = UAU in mRNA, what are the sequences of nucleotides corresponding to this sequence in the following? The mRNA strand (sense) The non-template DNA strand (sense or coding strand) The template DNA strand (antisense or non-coding stand) The tRNA anticodon

Solution

Answer:

(5)

(a)amino acid sequence of the peptide= Phe-Tyr-Phe-Tyr-Phe-Tyr-Phe

mRNA =5’-UUU UAU UUU UAU UUU UAU UUU-3’

(b) coding strand of DNA is mRNA like

5’-TTT TAT TTT TAT TTT TAT TTT -3’

(c) template DNA is complementary to mRNA (except it has T in place of U)

3’-AAA ATA AAA ATA AAA ATA AAA-5’

(d) tRNA anticodon is complementary to mRNA codons

3’-AAA AUA AAA AUA AAA AUA AAA-5’