Mutations

• What is a mutation?

  A change in the DNA base sequence
• What happens to the base sequence in a mutation?

  It changes, affecting amino acid coding
• What is the effect of a mutation on the triplet code?

  It can code for a different amino acid
• How do carcinogens affect mutations?

  They increase the risk of mutations
• What might happen if a protein made is an enzyme after a mutation?

  The shape of the active site may change
• Where do most mutations occur?

  In non-coding DNA
• How can a mutation in non-coding DNA affect gene expression?

  It can alter how genes are expressed
• What is the role of non-coding DNA?

  It controls the expression of genes
• What are the three ways mutations can change DNA base sequences?

  • Substitution
  • Insertion
  • Deletion
• What occurs during a substitution mutation?

  One base is changed for another base
• What is the effect of a substitution mutation on the DNA sequence TAG?

  It can change to TGG
• What happens during an insertion mutation?

  An extra base is inserted into the sequence
• What is the consequence of an insertion mutation?

  All bases shift along by one
• What occurs during a deletion mutation?

  One base is deleted from the sequence
• How does a change in one base affect enzyme function?

  It changes the amino acid coded
• What is the result of a different amino acid sequence in a protein?

  The protein may fold into a different shape
• How does a different shaped active site affect enzyme activity?

  It won't be complementary to the substrate
• What is the impact of mutations on enzyme catalysis?

  They can reduce the enzyme's catalytic ability
• What is the consequence of an enzyme not forming an enzyme-substrate complex?

  It won't be able to catalyze reactions effectively
• What percentage of mutations have very little effect?

  Most mutations