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प्रश्न
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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उत्तर
- 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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संबंधित प्रश्न
______ 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 statements is correct about the role of regulatory proteins in transcription in prokaryotes?
List the changes that the primary transcript undergoes to become functional mRNA.
Which of the following are the post-transcriptional events in an eukaryotic cell?
- Transport of pre-mRNA to cytoplasm prior to splicing.
- Removal of introns and joining of exons.
- Addition of methyl group at 5' end of hnRNA.
- 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 level of gene regulation involves the formation of the primary transcript in eukaryotes?
What is the primary mechanism of gene expression control in prokaryotes?
What enzyme does Escherichia coli produce to break down lactose?
Which type of control is exemplified by feedback repression?
