Question

Assess the possibility of errors occurring during the stages of protein synthesis, particularly during transcription and translation. Analyse the cause and effect of genetic mutations in DNA, including:

• Missense 

• Nonsense

• Silent

• Insertion

• Deletion

• Duplication

• frameshift

Provide examples of the impact that these errors may have on the end products of protein synthesis.

Answer 1

Missense

A genetic alteration in which a single base pair substitution alters the genetic code in a way that produces an amino acid that is different from the usual amino acid at that position. Some missense variants (or mutations) will alter the function of the protein.

Nonsense

A nonsense mutation is the substitution of a single base pair that leads to the appearance of a stop codon where previously there was a codon specifying an amino acid. The presence of this premature stop codon results in the production of a shortened, and likely nonfunctional, protein.

Silent

A silent mutation is a change in the sequence of nucleotide bases which constitutes DNA, without a subsequent change in the amino acid or the function of the overall protein. Sometimes a single amino acid will change, but if it has the same properties as the amino acid it replaced, little to no change will happen.

Insertion

Insertion is a type of mutation involving the addition of genetic material. An insertion mutation can be small, involving a single extra DNA base pair, or large, involving a piece of a chromosome.

Deletion

Deletion is a type of mutation involving the loss of genetic material. It can be small, involving a single missing DNA base pair, or large, involving a piece of a chromosome.

Duplication

Duplication is a type of mutation that involves the production of one or more copies of a gene or region of a chromosome. Gene and chromosome duplications occur in all organisms, though they are especially prominent among plants. Gene duplication is an important mechanism by which evolution occurs.

Frameshift

a mutation caused by the addition or deletion of a base pair or base pairs in the DNA of a gene resulting in the translation of the genetic code in an unnatural reading frame from the position of the mutation to the end of the gene.