MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
Regulatory proteins -
correct answer ✅help a cell sense internal changes and alter its
gene expression to match.
There are 2 forms of regulatory proteins: -
correct answer ✅- Repressors (negative control)
- Activators (positive control)
Repressors -
correct answer ✅bind to regulatory sequences in the DNA and
prevent transcription of target genes.
- some must first bind a small ligand.
Activators -
correct answer ✅bind to regulatory sequences in the DNA and
stimulate transcription of target genes.
- most must first bind a small ligand.
,MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
Microbes control gene expressions at several levels -
correct answer ✅- Alterations of DNA sequence
- Control of transcription
- Control of mRNA stability
- Translational control
- Post-translational control
Paradigm of the Lactose Operon -
correct answer ✅Scientist Jacques Monod and Francois Jacob -
genes could be regulated.
E. coli, enzymes used to metabolize lactose were inducible, glucose
were constitutive.
- 1965 nobel prize for his study of phage nysogeny.
,MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
LacZYA operna -
correct answer ✅E. coli was 1st gene regulatory system described.
Organization of LacZYA Opepn -
correct answer ✅
If lactose is absent then -
correct answer ✅LacI binds as a tetramer to operator region.
- represses the lac operon by preventing open complex formation
by RNA ploymerase.
If lactose is present then -
correct answer ✅B-galactosidase (LacZ) at low levels, cleaves and
rearranges lactose to make inducer allolactose.
- Allolactose binds to LacI, reducing affinity to operator allowing
induction of operon.
cAMP and cAMP receptor protein (CRP) -
correct answer ✅are required for the maximum expression of the
lac operon.
, MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
Catabolite repression -
correct answer ✅operon enabling catabolism of one nutrient is
repressed by the presence of a more favorable nutrient.
Diauxic growth -
correct answer ✅the biphasic curve if a culture growing in 2
carbon soruces.
Inducer exclusion -
correct answer ✅glucose transport by phosphotransferase system
causing catabolite repression by inhibiting the LacY permease
activity.
- if lactose can't enter the cell, lacZYA operon can't be induced.
Major regulator AraC -
correct answer ✅can repress or activate gene expression.
Answers (Grade A+)
Regulatory proteins -
correct answer ✅help a cell sense internal changes and alter its
gene expression to match.
There are 2 forms of regulatory proteins: -
correct answer ✅- Repressors (negative control)
- Activators (positive control)
Repressors -
correct answer ✅bind to regulatory sequences in the DNA and
prevent transcription of target genes.
- some must first bind a small ligand.
Activators -
correct answer ✅bind to regulatory sequences in the DNA and
stimulate transcription of target genes.
- most must first bind a small ligand.
,MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
Microbes control gene expressions at several levels -
correct answer ✅- Alterations of DNA sequence
- Control of transcription
- Control of mRNA stability
- Translational control
- Post-translational control
Paradigm of the Lactose Operon -
correct answer ✅Scientist Jacques Monod and Francois Jacob -
genes could be regulated.
E. coli, enzymes used to metabolize lactose were inducible, glucose
were constitutive.
- 1965 nobel prize for his study of phage nysogeny.
,MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
LacZYA operna -
correct answer ✅E. coli was 1st gene regulatory system described.
Organization of LacZYA Opepn -
correct answer ✅
If lactose is absent then -
correct answer ✅LacI binds as a tetramer to operator region.
- represses the lac operon by preventing open complex formation
by RNA ploymerase.
If lactose is present then -
correct answer ✅B-galactosidase (LacZ) at low levels, cleaves and
rearranges lactose to make inducer allolactose.
- Allolactose binds to LacI, reducing affinity to operator allowing
induction of operon.
cAMP and cAMP receptor protein (CRP) -
correct answer ✅are required for the maximum expression of the
lac operon.
, MBIO 3401 TTU Exam 2 Questions &
Answers (Grade A+)
Catabolite repression -
correct answer ✅operon enabling catabolism of one nutrient is
repressed by the presence of a more favorable nutrient.
Diauxic growth -
correct answer ✅the biphasic curve if a culture growing in 2
carbon soruces.
Inducer exclusion -
correct answer ✅glucose transport by phosphotransferase system
causing catabolite repression by inhibiting the LacY permease
activity.
- if lactose can't enter the cell, lacZYA operon can't be induced.
Major regulator AraC -
correct answer ✅can repress or activate gene expression.
