AP BIOLOGY

Detailed explanation-1: -Plasmids contain just a few genes, but they make a big difference to their host bacterium. The genes are usually not essential for the bacterium’s day-to-day survival – instead, they help the bacterium to overcome occasional stressful situations.

Detailed explanation-2: -Bacterial plasmids may encode genes for traits that are sometimes beneficial to their hosts, such as antimicrobial resistance, virulence, heavy metal tolerance, and the catabolism of unique nutrient sources.

Detailed explanation-3: -’Plasmids carry genes that help bacteria to adapt to new niches and stresses, playing a key role in bacterial evolution, ’ said Alvaro San Millan of Oxford University’s Department of Zoology. ‘In the last decades they have become especially relevant as vehicles for the spread of antibiotic resistance.

Detailed explanation-4: -A plasmid is a small, circular, double-stranded DNA molecule that is distinct from a cell’s chromosomal DNA. Plasmids naturally exist in bacterial cells, and they also occur in some eukaryotes. Often, the genes carried in plasmids provide bacteria with genetic advantages, such as antibiotic resistance.