Practice Questions

TLS Online TPP Program

#Question id: 16125

You are studying regulation of the yeast enzyme glutamine synthetase (GS), which is encoded by the GLN1 gene. You have isolated two mutants, designated gln2– and gln3–, that give decreased GS activity. Mating of either gln2– or gln3– haploids to wild type produces heterozygous diploids that show normal amounts of GS expression. When you cross either a gln2– or gln3– haploid to a gln1– strain the resulting diploids show normal expression of GS.
From these experiments, Classify the gln2– and gln3– mutations in terms of their basic genetic properties explaining the rationale behind your conclusions. Based on these properties make a proposal for the types of regulatory functions affected by the gln2– and gln3– mutations.

#SCPH01 Biochemistry

Both are uninducible, as they give decreased glutamine synthetase (GS) activity
Both are recessive, as mating them with wild type produces normal GS activity
Both are inducible, as they give decreased glutamine synthetase (GS) activity
Both are dominant, as mating them with wildtype produces normal GS activity.
gln3– are inducible while gln2–are uninducible, as they give decreased glutamine synthetase (GS) activity
only gln2– are recessive, as mating them with wildtype produces normal GS activity.
gln3– are uninducible while gln2–are inducible, as they give decreased glutamine synthetase (GS) activity
only gln3– are recessive, as mating them with wildtype produces normal GS activity.