Final answer:
Point mutations can change a single amino acid in a protein, causing significant alterations in its structure and function. In sickle cell anemia, such a mutation in hemoglobin leads to malformed red blood cells with serious health consequences. The precision of the genetic code means that even small mutations can have large effects on protein function.
Step-by-step explanation:
Explaining How Point Mutation Affects Hemoglobin Function: Point mutations in DNA can lead to changes in the amino acid sequence of a protein, which may alter its structure and function. For example, in sickle cell anemia, a single base substitution in the hemoglobin gene results in the amino acid valine replacing glutamic acid in the hemoglobin protein. This seemingly minor change (one out of approximately 600 amino acids in the hemoglobin protein) has significant consequences, leading to altered hemoglobin function and the sickle cell trait. The new hemoglobin structure can cause red blood cells to assume a sickled shape under certain conditions, blocking blood flow and impairing oxygen delivery. Such mutations are noteworthy because they underscore the precision required in the genetic code, where each trio of nucleotides, or a codon, encodes a specific amino acid. A mutation affecting even a single nucleotide can therefore lead to the incorporation of a different amino acid, potentially disrupting the protein's normal function.
If this disruption occurs in critical areas of the protein, such as the active site of an enzyme, the effects can be significant. The exact effect of a missense mutation will depend on the properties of the substituted amino acid and its location within the protein.