OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

Which component of the bacterial cell is used to carry the insulin gene in genetic modification?

1. Chromosome

2. Ribosome

3. Plasmid

4. Cell membrane

The correct answer is: Plasmid

In genetic modification, plasmids play a crucial role as vectors for carrying genes, including the insulin gene, into bacterial cells. Plasmids are small, circular pieces of DNA that exist independently of the bacterial chromosome and can replicate independently within the cell. This makes them ideal for introducing foreign genes, such as the one for insulin, into bacteria, allowing the bacteria to express the protein. Using plasmids allows scientists to easily manipulate and transfer the genetic material, making them essential tools in biotechnology and genetic engineering, particularly in the production of recombinant proteins like insulin. Other components, such as chromosomes, are the larger DNA structures that contain the bulk of the organism's genetic information but are not used as vectors in this context. Ribosomes are involved in protein synthesis and do not carry genetic information. The cell membrane acts as a protective barrier around the cell and is not involved in the genetic material transport process.