Question

"bacteria are poisoned by elemental oxygen" explain this

Answer 1

Anaerobes are the bacteria which are affected by elemental oxygen. oxygenas a electron in the final metabolic process other than anaerobes rely on molecules.Anaerobes cannot gain energy if oxygen is present evolution development is the reason for this.

Answer 2

Oxygen makes up 21% of the Earth’s atmosphere, and we need it to breathe. But early organisms would have found this environment toxic. Ancient bacteria evolved protective enzymes that prevented oxygen from damaging their DNA, but what evolutionary incentive did they have to do this? Researchers have discovered that ultraviolet light hitting the surface of glacial ice can release molecular oxygen. Bacteria colonies living near this ice would have needed to evolve this protective defense. They were then well equipped to handle the growth of atmospheric oxygen produced by other bacteria that would normally be toxic.

Two and a half billion years ago, when our evolutionary ancestors were little more than a twinkle in a bacterium’s plasma membrane, the process known as photosynthesis suddenly gained the ability to release molecular oxygen into Earth’s atmosphere, causing one of the largest environmental changes in the history of our planet. The organisms assumed responsible were the cyanobacteria, which are known to have evolved the ability to turn water, carbon dioxide, and sunlight into oxygen and sugar, and are still around today as the blue-green algae and the chloroplasts in all green plants.