Written By: Plasmid, in microbiology, an extrachromosomal genetic element that occurs in many bacterial strains. Plasmids are circular deoxyribonucleic acid (DNA) molecules that replicate independently of the bacterial chromosome. They are not essential for the bacterium but may confer a selective advantage.
A gnat /ËnÃ¦t/ is any of many species of tiny flying insects in the Dipterid suborder Nematocera, especially those in the families Mycetophilidae, Anisopodidae and Sciaridae. They can be both biting and non-biting. Most often they fly in large flocks resembling clouds.
Depending on the species, gnat eggs are laid on land or water. Larvae may be immobile or capable of movement by way of rocks and water plants. Adults range in size but usually are no larger than 33 mm. The larval and adult stages of the gnat are considered both beneficial and detrimental.epending on the species, gnat eggs are laid on land or water. Larvae may be immobile or capable of movement by way of rocks and water plants. Adults range in size but usually are no larger than 33 mm. The larval and adult stages of the gnat are considered both beneficial and detrimental.