Genetics Exam 2 (Gene Mutation and DNA
Repair) UPDATED ACTUAL Exam
Questions and CORRECT Answers
Mutation - CORRECT ANSWER - a heritable (inheritable) change in the genetic material, i.e.
change in nucleotide sequence.
Where mutations can occur - CORRECT ANSWER - anywhere on a DNA molecule.
However, if a mutation occurs in protein coding region, it can alter AA sequence, structure, and
function of a protein.
Germline Cells - CORRECT ANSWER - make gametes; reproductive cels; give rise to sperm
and eggs (huntington's disease)
Somatic Cells - CORRECT ANSWER - everything that a Germline cell doesn't do; non-
reproductive cells (cancer cells)
Point mutation - CORRECT ANSWER - a mutation that changes one of a few adjacent base
pairs at a single location ("point") on a DNA molecule. If a point mutation occurs in a gene, then
only that single gene will be affected.
Transition Mutation - CORRECT ANSWER - Purine-->Purine (A-T to G-C); base pair
substitution that effects at a DNA level; ANYWHERE on a DNA molecule
Transversion Mutation - CORRECT ANSWER - Purine-->Pyrimidine or Pyrimidine-->Purine
(C-G to G-C); base pair substitution effect at DNA level; ANYWHERE on a DNA molecule
Base pair effect on protein coding region - CORRECT ANSWER - silent (synonymous)
missense (non-synonymouse)
((conservative and non-conservative))
, nonsense
silent (synonymouse) mutation - CORRECT ANSWER - mutant codon codes for same AA as
a wild-type codon; evolutionarily neutral, no effect on survival and reproduction
missense (non-synonymous) mutation - CORRECT ANSWER - mutant codes for AA different
from AA encoded by wild-type codon
conservative missense mutation - CORRECT ANSWER - mutant codon codes AA chemically
similar to AA encoded by wild-type codon (e.g. wildtype codon AA, which encodes lysine, a
basic AA, is mutated to AGA-arginine)
conservative missense effect on p structure and function - CORRECT ANSWER - often
evolutionarily neutral, but not always; no way to tell which one it will be; only able to directly
assess function of affected protein.
Non-conservative missense mutation - CORRECT ANSWER - mutant codon for AA
chemically different from AA encoded by wild-type codon (e.g. wildtype codon AAA (lysine)
mutated to GAA (glutamic acid) )
Nonsense Mutation - CORRECT ANSWER - (non-conservative missense) codon for AA is
changed to stop codon; leads to premature translation termination.
Nonsense effect on p structure and function - CORRECT ANSWER - ASK LISSEMORE
Insertion & Deletion Mutations (DNA Level) - CORRECT ANSWER - insertion or deletion
of 1 or more bp
Insertion & Deletion Effect on Protein Coding Region - CORRECT ANSWER - frameshift
mutations occur
Repair) UPDATED ACTUAL Exam
Questions and CORRECT Answers
Mutation - CORRECT ANSWER - a heritable (inheritable) change in the genetic material, i.e.
change in nucleotide sequence.
Where mutations can occur - CORRECT ANSWER - anywhere on a DNA molecule.
However, if a mutation occurs in protein coding region, it can alter AA sequence, structure, and
function of a protein.
Germline Cells - CORRECT ANSWER - make gametes; reproductive cels; give rise to sperm
and eggs (huntington's disease)
Somatic Cells - CORRECT ANSWER - everything that a Germline cell doesn't do; non-
reproductive cells (cancer cells)
Point mutation - CORRECT ANSWER - a mutation that changes one of a few adjacent base
pairs at a single location ("point") on a DNA molecule. If a point mutation occurs in a gene, then
only that single gene will be affected.
Transition Mutation - CORRECT ANSWER - Purine-->Purine (A-T to G-C); base pair
substitution that effects at a DNA level; ANYWHERE on a DNA molecule
Transversion Mutation - CORRECT ANSWER - Purine-->Pyrimidine or Pyrimidine-->Purine
(C-G to G-C); base pair substitution effect at DNA level; ANYWHERE on a DNA molecule
Base pair effect on protein coding region - CORRECT ANSWER - silent (synonymous)
missense (non-synonymouse)
((conservative and non-conservative))
, nonsense
silent (synonymouse) mutation - CORRECT ANSWER - mutant codon codes for same AA as
a wild-type codon; evolutionarily neutral, no effect on survival and reproduction
missense (non-synonymous) mutation - CORRECT ANSWER - mutant codes for AA different
from AA encoded by wild-type codon
conservative missense mutation - CORRECT ANSWER - mutant codon codes AA chemically
similar to AA encoded by wild-type codon (e.g. wildtype codon AA, which encodes lysine, a
basic AA, is mutated to AGA-arginine)
conservative missense effect on p structure and function - CORRECT ANSWER - often
evolutionarily neutral, but not always; no way to tell which one it will be; only able to directly
assess function of affected protein.
Non-conservative missense mutation - CORRECT ANSWER - mutant codon for AA
chemically different from AA encoded by wild-type codon (e.g. wildtype codon AAA (lysine)
mutated to GAA (glutamic acid) )
Nonsense Mutation - CORRECT ANSWER - (non-conservative missense) codon for AA is
changed to stop codon; leads to premature translation termination.
Nonsense effect on p structure and function - CORRECT ANSWER - ASK LISSEMORE
Insertion & Deletion Mutations (DNA Level) - CORRECT ANSWER - insertion or deletion
of 1 or more bp
Insertion & Deletion Effect on Protein Coding Region - CORRECT ANSWER - frameshift
mutations occur
