Question

The DNA sequence shown encodes the last amino acids of a protein that has a total of 270 amino acids. The bolded base pairs indicate the translation reading frame.

5’ …….GCT AAG TAT TGC TCA AGA TTA GGA TGA TAA ATA ACT TGG 3’

3’ …….CGA TTA ATA ACG AGT TCT AAT CCT ACT ATT TAT TGA ACC 5’

Which is the template strand for transcription? Explain.

Answer 1

3’ …….CGA TTA ATA ACG AGT TCT AAT CCT ACT ATT TAT TGA ACC........ 5’

Transcription always proceeds in the direction 5' (5-prime) to 3' (3-prime) on the coding strand of DNA. The 3'-5' strand that serves as the template is called the "antisense" or noncoding or template strand and the 5'-3' strand (which has the same nucleotide sequence, with exception of "U"s for "T"s, as the subsequently transcribed mRNA) is the "sense" or "coding" or non-template strand.