Question

2. How might a mutation that causes a single letter change in the DNA sequence affect

your protein structure and function?

Answer 1

A single nucleotide change in the DNA, or a point mutation, can lead to a missense or nonsense mutation affecting protein structure and function. The consequences range from no effect to complete loss of function, as seen in diseases like sickle cell.

Step-by-step explanation:

A single nucleotide change in the DNA sequence, known as a point mutation, may affect protein structure and function in various ways. When such a mutation leads to a change in an amino acid, it's called a missense mutation. The impact of this mutation is determined by several factors, including the chemical properties of the new amino acid compared to the original one and its location within the protein. For instance, if the mutation occurs in the enzyme's active site, it could greatly alter the protein's function. Sometimes, proteins may remain partially functional, but in other cases, such as a nonsense mutation, which introduces a premature stop codon, the protein may be rendered non-functional.

Conditions like sickle cell disease, which involve a single amino acid change from glutamic acid to valine in hemoglobin, exemplify the serious consequences that can arise from such mutations. The altered properties of hemoglobin can lead to impaired oxygen transport, demonstrating how critical certain amino acid positions are to protein function. In contrast, silent mutations do not alter the amino acid and therefore do not affect the protein's function.

Answer 2

A mutation that causes a single letter change in the DNA sequence can affect your protein structure and function because the sequence of letters in a gene determines the sequence of amino acids in the protein that it encodes. A single letter change in the DNA alters the mRNA which alters the amino acid sequence of the resulting protein and sometimes that can cause serious results if it changes the way a protein works.

ex. sickle cell disease - a single letter swap in the gene that encodes the hemoglobin molecule results in deformed red blood cells

Hope that helps.