Question

General Biology lab report of Gene Expression and DNA Technology

please make sure to give more details

Q3). Frameshift mutations occur when you add or delete bases in multiples other than 3 at a time.

Frameshift Mutation please make sure to make a chart for TAC GGA TGG CTA ATG GTA CTC

DNA: TAC GGA TGG CTA ATG GTA CTC

mRNA:

amino acid sequence:

Q4). How does this polypeptide differ from the normal polypeptide on the Frameshift Mutation continuing question #3?

Q5). What kind of mutation caused the change in the polypeptide sequence?

Q6). Will this protein likely be functional? Why?

Answer 1

Frameshift mutation is one of the most damaging changes to the coding sequence of a protein. They are likely to cause large-scale changes to polypeptide length and chemical composition, resulting in a non-functional protein that most often disrupts the biochemical processes of a cell. This mutation not affect a single aminoacid change as we see in substituiton mutation but results in a totally different sequence of amino acids in the polyleptide chain. It starts changing codons from the point of mutation upto the last codon that is stop codon . We can understand it by taking example given in question 3.

3). Answer :-

DNA: TAC GGA TGG CTA ATG GTA CTC. Suppose mutation occurs at 2nd codon and one A base is added at the point as shown below.

Normal DNA -TAC GGA TGG CTA ATG GTA CTC Mutated DNA - TAC GGAA TGG CTA ATG GTA CTC

Normal mRNA- AUG CCU ACC GAU UAC CAU GAG mRNA of mutated DNA - AUG CCU UAC CGA UUA CCA UGA G

amino acid sequence: Met Pro Thr Asp Tyr His Glu Resulted amino acid sequence : Met Pro Tyr Arg - no more amino acid added because stop codon is present.

Note:-Bold letter showing changed sequence or codon or amino acids.

4). In the above taken example of frameshift mutation, mutated DNA has resulted a polypeptide having only 4 amino acids out of which 2 are different from normal sequence.

5). Nonsense mutation has terminated the chain after 4th amino acid.

6). No, this protein will not be functional as it is incomplete protein and also have different types of amino acids as compared to normal sequence. Function of protein depends on sequence specificity.