Transcription is prevented when _____ bind to a regulatory sequence, and stimulated when ____ bind to a regulatory sequence.
D) repressors; activators
Which of the following can be used to control sigma factors?
E) All of the above
Error-proof repair pathways include all the following EXCEPT
B) Nonhomologous end joining
Transcription initiation of the lac operon is enhanced when _____ interacts with RNA polymerase.
D) cAMP receptor protein
Attenuation is a common regulatory strategy used to control the transcription of operons that code for
D) Amino acid biosynthesis
In , French scientists Jacques Mnod and Fancois Jacob proposed the revolutionary idea that...
genes could be regulated
______ induces expression of the LacZYA operon
lactose
Lac operon in the absence of lactose:
- _____ binds as a tetramer to the operator region
- it ______ the lac operon by _______ open complex formation by RNA polymerase
- LacI
- represses, preventing
Lac operon in the presence of lactose:
- _______ (_____), when at low levels, cleaves and rearranges lactose to make the inducer allolactose
- Allolactose binds to LacI, _____ its affinity to th eoperator and thus ____ induction of the operon
- β-galactosidase (LacZ)
- reducing, allowing
Maximum expression of the lac operon requires the presence of ______ and ____ ____ ____ (CRP)
cAMP, cAMP receptor protein
The cAMP-CRP complex binds to the ______, and interacts with RNA pol to _____ the rate of transcription ______.
promoter, increase, initiation
In ______ repression, an operon enabling the catabolism of one nutrient is repressed by the presence of a more favorable nutrient (commonly glucose).
catabolite
Glucose _____ the lac operon.
represses
Glucose transport by the phosphotransferase system causes catabolite repression by inhibiting the ____ permease activity, which is termed _____ _____.
LacY, inducer exclusion (if lactose cannot enter the cell, the lacZYA operon cannot be induced)
DNA sites that bind regulatory proteins typically exhibit a sequence symmetry that allows unmbiguous recognition. Symmetry usually involves an ______ repeat.
inverted
Coupling of transcription and translation can be used to regulate gene expression by _____.
