K10MS W10 LAC OPERON TUTORIAL

K10MS W10 LAC OPERON TUTORIAL

by NUR BM

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​LO: explain the concept of operon and gene regulation

Multiple Choice

which of the following is NOT the component of lac operon?

• structural genes

• repressor protein

• promoter

• operator

​name and describe structure of each component of lac operon present based on the provided diagram

​lac operon

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• ​

Multiple Choice

which of the following enzyme produced when transcription of lac Y is successful?

• transacetylase

• RNA polymerase

• B galactosidase

• lactose permease

​structural genes

​explain how the structural genes are controlled as single unit.

structural gene contains only 1 promoter

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​RNA polymerase binds once and transcribed all structural genes at once producing single mRNA strand

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​advantage? increase efficiency of enzyme synthesise

Multiple Choice

which of the following process did not occur during lac operon expression?

• transcription

• mRNA synthesis

• protein synthesis

• DNA replication

Multiple Choice

single unit of gene expression increase efficiency of lactose metabolism in E. coli as follows EXCEPT ?

• mRNA is synthesized consecutively during each transcription

• the single transcribed mRNA has the code to synthesize all enzymes at once

• each structural genes contains separate promoter

• RNA polymerase binds at single promoter to transcribe all genes at once

​RNA polymerase

​explain its function and how it is required in lactose operon expression

​RNA polymerase

​RNA polymerase catalyze the transcription of structural genes (lac Z, lac Y and lac A)

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binds itself on promoter site when required

Multiple Choice

which of the following is the binding site of RNA polymerase

• operator

• repressor protein

• promoter

• structural genes

​respressor protein

​explain how the function of repressor protein is important in controlling the lac operon expression

​Repressor protein

​repressor protein binds on the operator

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​it blocks RNA polymerase from transcribing the structural genes

Multiple Choice

Which statement about Escherichia coli which has regulatory gene that has undergone mutation is true?

• Only β-galactosidase is produced

• Repressor produced binds with operator gene.

• RNA polymerase is unable to bind with promoter gene

• E. coli produces β-galactosidase, permease and transacetylase continuously.

​ALLOLACTOSE

• ​describe how allolactose is produced and its primary role

​ALLOLACTOSE

• allolactose is isomer of lactose

• ​produced only when lactose is present (individual drinks milk)

• ​binds to repressor protein

• ​inactivate repressor protein by altering its confirmation

• ​repressor protein can no longer binds to operator

Multiple Choice

In the lactose operon, both genes P and Q undergo the transcription process. Gene Q can only undergo transcription with the existence of lactose and at the same time, gene P product is released from R. Which of the following is true about the genes P, Q and R?

•  P Regulator gene     Q Structural gene

  R Operator gene

• R Regulator gene     P Structural gene

  Q Operator gene

•  R Regulator gene     Q Structural gene

  P Operator gene

•  P promoter gene     Q Regulator gene

  R Operator gene

Multiple Choice

Which of the following statements are true about lactose operon in the presence of lactose?

I. The regulator gene produces an active repressor molecule.

II. Lactose binds with the repressor molecule.

III. The inactive repressor molecule binds to the promoter.

IV. The RNA polymerase binds to the operator.

V. Transcription of structural gene occurs.

•      I, II and III

•       I, II and V

•   I, III and IV

• I, II, IV and V

Open Ended

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