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Question
Which of the following statements is correct about the role of regulatory proteins in transcription in prokaryotes?
Options
They only increase expression
They only decrease expression
They interact with RNA polymerase but do not affect the expression
They can act both as activators and as repressors
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Solution
They can act both as activators and as repressors
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RELATED QUESTIONS
In E.coli, three enzymes β- galactosidase, permease and transacetylase are produced in the presence of lactose. Explain why the enzymes are not synthesized in the absence of lactose.
Distinguish between structural gene, regulatory gene and operator gene.
Which of the following is not a level at which gene expression can be regulated in eukaryotes?
The gene which codes for enzyme β-galactosidase ______.
The image below shows the result of plating bacteria in a chromogenic medium after incorporating the gene of interest in the plasmid. Some plates had blue colonies; some plates had white colonies. A single bacterium extracted from Plate I, II, and III is shown below:
On the basis of your observations:
- Identify the plate(s) which is/are white. Give a reason.
- Identify the plate(s) which is/are blue. Give a reason.
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List the changes that the primary transcript undergoes to become functional mRNA.
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- Transport of pre-mRNA to cytoplasm prior to splicing.
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- Addition of adenine residues at 3' end of hnRNA.
- Base pairing of two complementary RNAs.
Choose the correct answer from the options given below:
Match List I with List II:
| List I | List II |
| A. Gene ‘a’ | I. β-galactosidase |
| B. Gene ‘y’ | II. Transacetylase |
| C. Gene ‘i’ | III. Permease |
| D. Gene ‘z’ | IV. Repressor protein |
Choose the correct answer from the options given below:
Which of the following best describes gene regulation?
Which process is responsible for development and differentiation from embryo to adult organism?
Which level of gene regulation specifically controls splicing in eukaryotes?
At which level of gene regulation is control exerted during protein synthesis in eukaryotes?
What enzyme does Escherichia coli produce to break down lactose?
What are the two products formed when E. coli β-galactosidase breaks down lactose?
What term describes the process by which inducible enzymes are produced?
What is feedback repression?
