Final answer:
Mutations are changes to the order of nucleotides in a segment of DNA that codes for a protein. Mutations can be deletions, insertions, or substitutions, leading to frameshift mutations or different amino acids being incorporated into proteins.
Step-by-step explanation:
Changes to the order of nucleotides in a segment of DNA that codes for a protein are called mutations. These changes can have various effects on an organism depending on the type of mutation. For example, a deletion mutation is the loss of one or more nucleotides, which can cause a frameshift mutation if it results in the alteration of the reading frame of the genetic sequence. A substitution mutation might result in a different amino acid in the protein, and a frameshift mutation often leads to the synthesis of a completely nonfunctional protein due to a shift in the reading frame caused by an insertion or deletion. For instance, deleting one nucleotide out of the trio that forms a codon can change the entire amino acid sequence encoded by the gene.