Question

A point mutation changes one nucleotide at a random location in human DNA. How likely is the mutation to cause a change In the amino acid sequence of a protein? Apply scientific reasoning to your prediction.

Answer 1

A point mutation changes a single nucleotide base in DNA and can result in silent, missense, or nonsense mutations. While a silent mutation does not typically alter protein function, missense and nonsense mutations can have significant effects if they occur in critical regions of the protein.

Step-by-step explanation:

When considering how likely a point mutation is to cause a change in the amino acid sequence of a protein, several factors come into play. A point mutation refers to the alteration of a single nucleotide base in the DNA, which may result in a silent, missense, or nonsense mutation.

A silent mutation generally does not affect the amino acid sequence due to the redundancy of the genetic code. However, a missense mutation leads to the incorporation of a different amino acid, and this can vary in impact depending on the chemical properties and the role of the new amino acid within the protein. A nonsense mutation, on the other hand, transforms a sense codon into a stop codon, potentially leading to truncated, often non-functional proteins.

Considering the genetic degeneracy, many point mutations may be silent and thus do not affect the protein's functionality. However, if a missense or nonsense mutation occurs, particularly in a crucial region of the protein such as the active site, the consequences can be significant and potentially deleterious, as seen in disorders like sickle-cell disease.

Answer 2

Answer: Very unlikely

Step-by-step explanation:

Generally, point mutation can be easily reversed by another point mutation, so

before any changes occur in the amino acid sequence, it would have been corrected.

However, when point mutation occurs within the protein coding region of a gene it may results in the change of a single nucleotide to cause the substitution of a different amino acid (which renders the protein non-functional) as in the case of sickle-cell disease.

And this kind of point mutation is specifically called Missense mutation.

Above all, because point mutation is easily reversible, it is very unlikely to change the amino acid sequence of a protein