Conjugation is observed in which organisms?

• A. Paramecia and some prokaryotes
• B. Only plants
• C. Only animals
• D. Only viruses

Answer: (A)

Conjugation is a direct-contact method of genetic exchange between cells. In bacteria, a donor cell passes DNA to a recipient through a physical bridge called a pilus, often transferring plasmids or parts of the chromosome—this is horizontal gene transfer, not reproduction. Some single-celled eukaryotes, such as Paramecium, also undergo conjugation where the two cells exchange genetic material during a mating-like process, increasing genetic diversity.

Plants and animals reproduce through other means (sexual reproduction or asexual reproduction) but not via this direct cell-to-cell DNA transfer. Viruses don’t conjugate in the classic sense either; they don’t exchange DNA through mating bridges between cells.

Therefore, the organisms in which conjugation is observed are Paramecia and some prokaryotes.