NEET Solved Paper 2019 Question 23
Question: Under which of the following conditions will there be no change in the reading frame of following mRNA? [NEET 5-5-2019]
5’ AACAGCGGUGCUAUU 3'
Options:
A) Insertion of A and G at 4th and 5th positions respectively
B) Deletion of GGU from 7th, 8th and 9th positions
C) Insertion of G at 5th positions
D) Deletion of G from 5th positions
Show Answer
Answer:
Correct Answer: B
Solution:
- GGU deletion, i.e. three nucleotides has no effect on the reading frame. Because each codon is made up of three consecutive nucleotides, deleting or inserting three or multiples of three nucleotides has no effect on the reading frame. Frame-shift mutation occurs when one or two nucleotides are inserted or deleted, changing the entire reading frame.
