Chapter 7 Microbial Genetics Plasmids Circular genetic elements that reproduce autonomously and have an extra chromosomal existence 1-1000 KB in size Most are circular double- stranded dna. some linear ds DNA Transmitted from cell to cell via conjugation process Some can integrated into chromosome Can carry a variety of genes for production of toxin, resistance to antibiotics and heavy metals.Chapter 7 Microbial Genetics Plasmids • Circular genetic elements that reproduce autonomously and have an extra￾chromosomal existence. – 1-1000 KB in size – Most are circular double￾stranded DNA, some linear ds DNA – Transmitted from cell to cell via conjugation process – Some can integrated into chromosome – Can carry a variety of genes for production of toxin, resistance to antibiotics and heavy metals