1 The following schematic represents a yeast gene and its va

1. The following schematic represents a yeast gene and its various elements:

Indicate the predicted sizes of each of the following:

a) Pre-mRNA (non processed)

b) mRNA

c) Protein

d) mRNA from a gene with a point mutation creating a stop codon at position 1698

e) Protein from a gene with a point mutation creating a stop codon at position 1698

PLEASE ANSWER ALL QUESTIONS AND EXPLAIN I WANT TO UNDERSTAND !

The following schematic represents a yeast gene and its various elements (1600) (1850) (A) (200) ATG (510) (1060) (2110) Promoter Transcription terminator Exon ntron Coding DNA TAG (2510) (2890)

Solution

a). pre-mRNA will have all sequence form promotor till terminaor. But it will not have promotor and terminator sequences. So its from 200 - 2890 = 2690 bp

b)mRNA - It will have only exons and not the introns. So add up all the exons.

= (1060-200) + (1850- 1600) + (2510 - 2110) = 860+250+400 = 1510 bp

c)Protein - it will have all exons almost same as mRNA length. But some sequences near the ATG are lost in the polypeptide. i.e 1510 - ( 510 - 200) = 1200

d) If a stop codon is created at 1698, then the mRNA terminates there. So it will have 860 + (1698 - 1600) = 958

e) Protein sequence will be truncated. i.e 648.