Types of mutation

Question 1

Substitution

Answer 1

• one or more bases are replaced for another
• can result in no change due to degenerate code
• 1 codon change = 1 amino acid chain

Question 2

Insertion

Answer 2

• one or more bases added to the sequence
• frameshift : codons change downstream of mutation leads to sequence change
• NO frameshift if multiple of base 3 bases added, extra codons = extra amino acids

Question 3

Deletion

Answer 3

• one or more bases are lost from base sequence
  -Frameshift if non-multiple of 3 bases removed
  -if multiple of 3 bases lost no frameshift but missing amino acids

Question 4

Inversion

Answer 4

-sequence of bases is separated from DNA and inserted at the same position, backwards
- no frameshift
- could lead to change in amino acids encoded by inverse bases or silent mutation
- harmful as original gene can’t be expressed from that chromosome

Question 5

Duplication

Answer 5

• sequence of bases is inserted multiple times
• if not multiple of 3 bases frameshift occurs so change in amino acid sequence
• second copy can mutate which develops new functions

Question 6

Translocation

Answer 6

• sequence of bases taken out and inserted at a different position on a chromosome
• significat impact on gene expression and amino acid sequences
• happens when crossing over occurs with non-homologous chromosomes