A nonsense mutation (a) causes one amino acid to be...

A nonsense mutation (a) causes one amino acid to be substituted for another in a polypeptide chain (b) results from the deletion of one or two bases, leading to a shift in the reading frame $(c)$ results from the insertion of one or two bases, leading to a shift in the reading frame (d) results from the insertion of a transposition (e) usually results in the formation of an abnormally short polypeptide chain

Labs

Want to see this concept in action?

NEW

Explore this concept interactively to see how it behaves as you change inputs.

View Labs

Key Concepts

Missense Mutation

A missense mutation is another type of point mutation where a nucleotide change results in the substitution of one amino acid for another in the protein. Unlike nonsense mutations, missense mutations do not create a stop codon but can still significantly alter protein function depending on the properties of the substituted amino acid.

Frameshift Mutation

A frameshift mutation results from the insertion or deletion of nucleotides in numbers not divisible by three, causing a shift in the reading frame of the codons during translation. This leads to an entirely different sequence of amino acids downstream of the mutation. It is important to note that nonsense mutations are usually point mutations and do not involve frame shifts.

Premature Termination Codon

This is the stop codon created as a result of a nonsense mutation. When a premature termination codon is introduced into the mRNA, it causes the ribosome to halt protein synthesis sooner than intended, which typically yields an incomplete and dysfunctional protein.

Nonsense Mutation

A nonsense mutation is a type of point mutation where a single nucleotide change converts a codon specifying an amino acid into a stop codon. This premature stop signal terminates translation early, leading to the production of a shortened, and usually nonfunctional, polypeptide chain.

Transcript

00:01 So this question is asking us about the types of mutations and specifically nonsense mutations.

00:06 So let's go over the three major types of mutations, silent mutations, non -sense mutations, and mis -sense mutations.

00:13 So say we have a normal dna strand that's supposed to have a t -t and a c.

00:19 The m -r -n -a would be a -a -g, and the protein itself would be lysine.

00:27 However, in a silent mutation, if this t gets, this c gets changed to a t, then our dna strand would read ttt, m rna would read aaa.

00:45 However, aaa is the codon still for lysine.

00:50 So this is called a silent mutation because the protein is the same even though a mutation occurred.

00:59 Next up is a nonsense mutation.

01:02 So say this t was mutated to an a in the dna strand.

01:09 So we had atc in our dna.

01:12 This a would then turn into a u, and the codon now would read u -a -g.

01:19 However, u -a -g codes for a stop.

01:25 So mis -sense mutation or nonsense mutations codes for stop codons.

01:31 A miscense mutation would be if this t was mutated to a g.

01:38 So now the dna strand reads tgc.

01:41 The m rna strand would read acg, and now the protein instead of coding for the original lysine, now the protein instead codes for threanine...

Please give Ace some feedback