lecture 7

Question 1

mutation

Answer 1

• change in genetic material of a cell/virus
• point mutations are chemical changes in one base pair of gene
• change of single nucleotide in DNA can lead to production of abnormal protein

Question 2

point mutations

Answer 2

• base pair substitution: replacement of a nucleotide and its partner with different nucleotide pair (no frame shift)
• base pair insertions/deletions: addition/loss of nucleotide pairs in gene sequence (frame shift)

Question 3

silent substitutions

Answer 3

• no change in amino acid

Question 4

missense substitutions

Answer 4

• change in one aminoa acid to another

Question 5

nonsense substitutions

Answer 5

• change in amino acid into stop codon

Question 6

frameshift mutation

Answer 6

• can cause immediate nonsense
• can cause extensive missense

Question 7

3 bp deletion

Answer 7

• no frameshift, one amino missing

Question 8

mutation and protein function

Answer 8

• insertions/deletions have disastrous effect on protein function than substitutions (alter reading frame)
• silent mutations have no effect on amino acid produced by codon (redundancy in genetic code)
• nonsense mutations change amino acid into stop codon (leading to nofunctional protein)
  -missense mutations result in different amino acid produced (impact depends on how amino acid sub affect tertirary and quaternary protein structure and active site)

Question 9

mutation

Answer 9

• spontaneous = occur during DNA replication, recombination, repair
• mutagens = physical/chemical agents causing mutations