Welcome to the Quiz!
This quiz contains 14 questions from a mix of 1 subtopics.
What is an operon?
a type of protein
a type of enzyme
a cluster of genes controlled by a single promoter
a non-coding region of DNA
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What does the lac operon enable Escherichia coli to do?
break down fats
use lactose as an energy source
use glucose as an energy source
break down proteins
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What happens when lactose is absent in the regulation of the lac operon?
the repressor protein changes shape and is released from the operator region
the repressor binds to the operator
the structural genes are transcribed
RNA polymerase can bind to the promoter and initiate transcription
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What happens when lactose is present in the regulation of the lac operon?
the repressor binds to the operator
RNA polymerase is blocked from the promoter
lactose binds to the repressor protein
no transcription of the structural genes occurs
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What is the role of the operator region in an operon?
it codes for proteins, typically enzymes
it is where RNA polymerase binds to initiate transcription
it encodes proteins that regulate the expression of the structural genes
it is a sequence where regulatory proteins can bind
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What is the role of the promoter region in an operon?
it is a sequence where regulatory proteins can bind
it codes for proteins, typically enzymes
it is where RNA polymerase binds to initiate transcription
it encodes proteins that regulate the expression of the structural genes
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What is the function of the lacI regulatory gene of the lac operon?
it modifies lactose or its by-products
it breaks down lactose into glucose and galactose
it transports lactose into the cell
it produces a repressor protein that controls the operon's activity
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What happens when the repressor protein binds to the operator region in the regulation of the lac operon?
the repressor protein changes shape and is released from the operator region
RNA polymerase is blocked from the promoter
RNA polymerase can bind to the promoter and initiate transcription
the structural genes are transcribed
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What happens when lactose binds to the repressor protein in the regulation of the lac operon?
no transcription of the structural genes occurs
RNA polymerase is blocked from the promoter
the repressor protein changes shape and is released from the operator region
the repressor binds to the operator
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What is the function of the structural genes in an operon?
they are a sequence where regulatory proteins can bind
they are the site where RNA polymerase binds to initiate transcription
they encode proteins that regulate the expression of the other genes
they code for proteins, typically enzymes
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What happens when the repressor protein is released from the operator region in the regulation of the lac operon?
no transcription of the structural genes occurs
RNA polymerase can bind to the promoter and initiate transcription
RNA polymerase is blocked from the promoter
the repressor binds to the operator again
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What is the preferred energy source of E. coli?
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What happens when both glucose and lactose are present in the regulation of the lac operon?
lactose metabolism is optimised
the CRP-cAMP complex upregulates the transcription of the lac operon
lactose metabolism enzymes are produced
the CRP-cAMP complex cannot form
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What happens when cAMP levels increase in the regulation of the lac operon by glucose?
cAMP binds to the cAMP receptor protein (CRP)
the lac operon's transcription is downregulated
lactose metabolism enzymes are not produced
the CRP-cAMP complex cannot form
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