6.7.A—Describe the various types of mutation

Describe the various types of mutation.

• Alterations in a DNA sequence are mutations that can cause changes in the type or amount of the protein produced and the consequent phenotype. DNA mutations can be beneficial, detrimental, or neutral based on the effect or the lack of effect they have on the resulting nucleic acid or protein and the phenotypes that are conferred by the protein.
  • i. Point mutations occur when one nucleotide has been substituted for a diff erent nucleotide.
  • ii. Frameshift mutations occur when one or more nucleotides are ins erted or deleted, causing the reading frame to be shifted.
  • iii. Nonsense mutations occur when there is a point mutation that causes a pr emature stop.
  • iv. Silent mutations occur when the change in the nucleotide sequence has no eff ect on the amino acid sequence.
  • Exclusion: Knowledge of specific mutations and their effects is beyond the scope of the AP Exam.