Question

Cyanobacteria use the process of

to produce energy, and oxygen is given off as a waste product.

Answer 1

Photosynthesis utilizes water as an electron donor in cyanobacteria in general and creates oxygen as a by-product, although some can even use hydrogen sulfide, a process that occurs among other photosynthetic bacteria, such as purple sulfur bacteria. Carbon dioxide is reduced via the Calvin cycle to form carbohydrates.