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WorksheetsOperons
Total questions: 15
Worksheet time: 12mins
You want your bacterial culture to grow well so you made an enriched media with all forms of carbohydrates. Which of this carbohydrate should you restore first if you want the culture to keep growing at the same rate?
Glucose
Lactose
Galactose
Fructose
Which of these operons is anabolic?
Lac
Ara
Trp
Phe
Which of these systems give the best mode for turning trp operon off?
Repressor
Attenuator
Repressor with a downstream poly A tail
Repressor with an attenuator
A Lac repressor is a tetramer repressed when bound to the inducer. The trp repressor is a ____________________
Dimer inactivated when bound to the inducer
Dimer activated on inducer binding
Tetramer inactivated on inducer binding
Tetramer activated on inducer binding
When uncharged tRNA concentration is low what will you expect as the activity of tryptophan operon?
Low
Medium
High
Very high
We know that lactose has a positive impact on the activity of the lac operon. Tryptophan’s presence has a ________________
Positive feedback
Negative feedback
No difference
Highly positive impact
Which segments of the attenuator together form the repression loop?
Segment 1-2
Segment 2-3
Segment 3-4
Segment 1-4
Which of these properties do not agree with trp operon attenuator?
It brings about repression of trp operon
It consists of one stem loop system
It has two codons for tryptophan in sequence
Ribosome stalls at the attenuator
Which of the Ara operon regulation site is actually preventing RNA polymerase from binding and producing the Ara genes BAD?
O1
O2
P
Z
Which of these Ara genes is a mode of feedback autoregulation?
Ara A
Ara B
Ara C
Ara D
Which of the Ara promoter regulation is controlled by binding of repressors on the O1 regulating unit?
PA
PB
PC
PD
In negatively regulated operon the bound repressor will
inhibit transcription
Enhance the activity of RNA polymerase
Facilitate transcription
Decrease the enzymatic ectivity of RNA polymerase
In the absence of glucose, the binding of CRP-cAMP complex to the region near to the lac promoter will
No significant effect on the transcription of lac genes
Cause the release of RNA polymerase from the promoter
Decrease transcription of lac genes
Increase transcription of lac genes
The lac repressor have which of the following DNA binding motif
Zinc Finger
Homodomain
Leucine zipper
Helix-turn-helix
The functional lac repressor is a
Dimer of identical monomers
Tetramer of two identical dimers
Tetramer of identical monomers
Trimer of identical monomers
