Question

Bacterial cells, are allowed to grow with a plasmid on a nutrient medium. Which of the following is true for bacterial cells that took up the plasmid?

• A. Plasmid should contain an auxotrophic mutation, and the medium should contain the missing nutrient.
• B. Plasmid should contain a gene for producing a nutrient, and the bacterial chromosome should contain an auxotrophic mutation.
• C. Bacterial chromosome should contain an antibiotic resistance gene, and the medium should contain the antibiotic.
• D. Plasmid should contain a gene for producing an antibiotic, and the bacterial chromosome should contain a gene for antibiotic resistance.
• E. Bacterial chromosome should contain an auxotrophic mutation, and the medium should contain the missing nutrient.

Answer 1

The correct option is B Plasmid should contain a gene for producing a nutrient, and the bacterial chromosome should contain an auxotrophic mutation.

If bacterial cells, are allowed to grow with a plasmid on a nutrient medium, the bacteria will take up the plasmid. This happens if the bacterial chromosomes are auxotrophic, which means it is unable to synthesize a particular organic compound required for its growth. The required gene for production of the organic compound, is hired from the plasmid, introduced in the nutrient medium. In short, the bacteria will take up the plasmid which has a gene for producing a nutrient and it gets incorporated into the bacterial chromosome.
So, the correct answer is option B.