Small accessory chromosomes found in bacteria and useful in recombinant DNA are called what?

Small accessory chromosomes found in bacteria and useful in recombinant DNA are called what?

• A. Chromosomes
• B. Ribosomes
• C. Plasmids
• D. Mitochondria

Answer: (C)

Plasmids are small, circular DNA molecules that exist outside the bacterial chromosome. They replicate independently and can carry extra genes, including those useful for cloning foreign DNA. In recombinant DNA work, scientists engineer plasmids to carry target genes and often include selectable markers (like antibiotic resistance) to identify cells that have taken up the plasmid. This makes plasmids ideal tools for gene cloning and expression. In contrast, the main bacterial chromosome holds essential genes, ribosomes are the protein-building machines, and mitochondria are energy-producing organelles found in eukaryotes, not features used for bacterial recombinant DNA.

Plasmids are small, circular DNA molecules that exist outside the bacterial chromosome. They replicate independently and can carry extra genes, including those useful for cloning foreign DNA. In recombinant DNA work, scientists engineer plasmids to carry target genes and often include selectable markers (like antibiotic resistance) to identify cells that have taken up the plasmid. This makes plasmids ideal tools for gene cloning and expression. In contrast, the main bacterial chromosome holds essential genes, ribosomes are the protein-building machines, and mitochondria are energy-producing organelles found in eukaryotes, not features used for bacterial recombinant DNA.