molecular genetics - mutation Exam Questions
with Correct Answers
1. how to determine a gene's function correct answers: study mutants that lack the
gene or express an altered version of it
2. another name for a complete loss of function mutation correct
answers: null or amorph mutation
3. null/amorph/complete loss of function mutation correct answers: mutants
with no remaining gene function; no functional gene products are made
4. null alleles or mutation can arise by what defects in gene expression
correct answers: transcrip- tional null, translational null, mutation in the produced protein
5. transcriptional null correct answers: no functional rna is made
6. translational null correct answers: failed to produce a protein product
7. another name for a partial loss of function mutation correct answers:
hypomorphs or weak-allele mutation
8. partial loss of function correct answers: mutants producing some degree of activity but
not enough to provide wild type activity
9. how can hypomorphic mutations arise correct answers: reduced levels of
transcription, reduced mrna stability, less active or lesser amount of protein product is made
10. can essential genes obtain a null mutant? correct answers: no - a null
mutant causes lethality. they can obtain a hypomorphic mutation bc it allows enough function
for survival
11. another name for a gain of function mutation correct answers:
neomorphic mutation
12. gain of function mutation correct answers: a mutation that causes a gene to be
active in an abnormal time or place
13. what kind of dominance do mutations have? correct answers: they can
be either recessive or dominant
14. another name for a dominant negative nutation correct answers:
antimorphic mutation
15. antimorphic/dominant negative mutation correct answers: a mutation
that results in protein products that antagonize or poison the wild type protein
16. what phenotype is expected from an antimorphic mutation?
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with Correct Answers
1. how to determine a gene's function correct answers: study mutants that lack the
gene or express an altered version of it
2. another name for a complete loss of function mutation correct
answers: null or amorph mutation
3. null/amorph/complete loss of function mutation correct answers: mutants
with no remaining gene function; no functional gene products are made
4. null alleles or mutation can arise by what defects in gene expression
correct answers: transcrip- tional null, translational null, mutation in the produced protein
5. transcriptional null correct answers: no functional rna is made
6. translational null correct answers: failed to produce a protein product
7. another name for a partial loss of function mutation correct answers:
hypomorphs or weak-allele mutation
8. partial loss of function correct answers: mutants producing some degree of activity but
not enough to provide wild type activity
9. how can hypomorphic mutations arise correct answers: reduced levels of
transcription, reduced mrna stability, less active or lesser amount of protein product is made
10. can essential genes obtain a null mutant? correct answers: no - a null
mutant causes lethality. they can obtain a hypomorphic mutation bc it allows enough function
for survival
11. another name for a gain of function mutation correct answers:
neomorphic mutation
12. gain of function mutation correct answers: a mutation that causes a gene to be
active in an abnormal time or place
13. what kind of dominance do mutations have? correct answers: they can
be either recessive or dominant
14. another name for a dominant negative nutation correct answers:
antimorphic mutation
15. antimorphic/dominant negative mutation correct answers: a mutation
that results in protein products that antagonize or poison the wild type protein
16. what phenotype is expected from an antimorphic mutation?
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4
