question from free 150 (2007) mol. bio. - saintdizzy

[ArchivalUser]

A normal peptide has 100 amino acids.
Following mutation, it has only 20; 1–10 are the
same as the normal peptide; 11–20 differ from
the normal peptide. Which of the following
mutations occurred?
(A) Nucleotide deletion in the codon for
amino acid 11 (codon 11)
(B) Nucleotide deletion in codon 20
© Nucleotide deletion in the intervening
sequence
(D) Nucleotide substitution in codon 11
(E) Nucleotide substitution in codon 20

[ArchivalUser]

its a frameshift. is it?

[ArchivalUser]

aa

[ArchivalUser]

notym can u explain a little please.

[ArchivalUser]

I think the answer is A.
It is a frame shift deletion and this is responsible for the change in the normal peptide from 11 to 20.
B would have been nonsense and the 11-20 peptide will be normal
E and D could be silent or missense
C has problem with spliceosome and normally cause failure to remove exons hence causing longer and not shorter amino acids or addition of a fragmented portion to the normal aa

[ArchivalUser]

@ saint dizzy
A & B ARE FRAME SHIFT
bt a SHOWS CHANGE OF AACID SEQ FROM 11TH aacid whic the q is asking.
WHERE AS B SHOWS CHANGE IN AACID SEQ FROM 20 TH
CC NOT SURE BT I THINK IT HAS PB IN NONCODING SITE THATS INTRON OF MRNA SO affect on actual coding seq dats exon ChANGE IN aacid seq
D & E substitution yes they can b missense or also stop codon can b formed with just 10 0r 19 aminoacid al
if d is misense then similar aminacid n no chamge esp from 11 -20 til end
if e missense then also no change till 19th aminoacid n similar 20 aminoacid