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.
The difference is that the worker bees (female) and the queen bee have stingers, while the drones (male) do not. The workers look after the queen, bring up the young, keep â¦ the hive clean, defend the hive against intruders and can even lay eggs in certain circumstances.