MMSC 491 EXAM 3 QUESTIONS WITH VERIFIED
ANSWERS
A mutation that does not cause a disease but that is unstable at mitosis and meiosis
and can change into a pathogenic mutation - Answers - A premutation
A pathogenic mutation that us unstable at mitosis and meiosis and can result in
progressively sever phenotypes - Answers - A dynamic mutation
A type of mutation that results in genetic mosaicism - Answers - A post-zygotic
(somatic) mutation
Interpret the following chromosome: 46,XX,del(15)(q11q13) - Answers - A female with
an interstitial deletion on the long arm of chromsome 15 with breakpoints at q11 and
q13
A class of mutation that is quite frequently associated with a gain of function - Answers -
A missense mutation
A nonsense mutation would be expected to result in - Answers - Production of a
polypeptide shorter than normally expected
A silent mutation - Answers - Results in a mutated coded that specifies the same amino
acid as the original codon
Which of the following amino acid substitutions would be considered to be a
conservative substitution f the original amino acid was Arg - Answers - Lysine (Arg), (R)
Which if any of the following statements is false? - Answers - False: When a gain of
function allele is known to be pathogenic in a single gene disorder, a heterozygote will
always show disease symptoms
True:
1. A null allele is one where the gene has been deleted or recieved an inactivating
mutation causing complete loss of gene function
2. Inactivating point mutations are common cause of pathogenesis oin recessively
inherited disorders
3. Inactivating point mutations are common cause of pathogeneiss in dominantly
inherited disorders
Which of the following is a disease whose molecular basis is due to the unstable
expansion of CAG repeats encoding polyglutamine - Answers - Huntington disease
ANSWERS
A mutation that does not cause a disease but that is unstable at mitosis and meiosis
and can change into a pathogenic mutation - Answers - A premutation
A pathogenic mutation that us unstable at mitosis and meiosis and can result in
progressively sever phenotypes - Answers - A dynamic mutation
A type of mutation that results in genetic mosaicism - Answers - A post-zygotic
(somatic) mutation
Interpret the following chromosome: 46,XX,del(15)(q11q13) - Answers - A female with
an interstitial deletion on the long arm of chromsome 15 with breakpoints at q11 and
q13
A class of mutation that is quite frequently associated with a gain of function - Answers -
A missense mutation
A nonsense mutation would be expected to result in - Answers - Production of a
polypeptide shorter than normally expected
A silent mutation - Answers - Results in a mutated coded that specifies the same amino
acid as the original codon
Which of the following amino acid substitutions would be considered to be a
conservative substitution f the original amino acid was Arg - Answers - Lysine (Arg), (R)
Which if any of the following statements is false? - Answers - False: When a gain of
function allele is known to be pathogenic in a single gene disorder, a heterozygote will
always show disease symptoms
True:
1. A null allele is one where the gene has been deleted or recieved an inactivating
mutation causing complete loss of gene function
2. Inactivating point mutations are common cause of pathogenesis oin recessively
inherited disorders
3. Inactivating point mutations are common cause of pathogeneiss in dominantly
inherited disorders
Which of the following is a disease whose molecular basis is due to the unstable
expansion of CAG repeats encoding polyglutamine - Answers - Huntington disease
