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Question
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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Solution
- Plate I, the b-galactosidase enzyme is responsible for the blue colour. Gene is inserted in the b-galactosidase site of the plasmid, thereby causing insertional inactivation of the enzyme, so no blue colour is made.
- Plate II - Gene of interest not inserted in the plasmid.
Plate III - No plasmid
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RELATED QUESTIONS
______ refers to the phenomenon by which a set of genes are switched on when there is necessity to metabolise a new substrate.
Which of the following is not a level at which gene expression can be regulated in eukaryotes?
Which of the following statements is correct about the role of regulatory proteins in transcription in prokaryotes?
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:
Gene regulation can be described as switching genes ON or OFF according to which two factors?
Which level of gene regulation specifically controls splicing in eukaryotes?
What is the primary mechanism of gene expression control in prokaryotes?
What term describes the process by which inducible enzymes are produced?
What is the molecule that triggers the synthesis of an inducible enzyme called?
What is feedback repression?
