Included in this category are the cyanobacteria, a group of bacteria formerly known as the blue-green algae because they have chlorophyll, and thus the ability to photosynthesize their food. They were re-categorized as bacteria rather than algae when researchers determined that the organisms were more similar to bacteria than to algae. All bacterial cells have a cell wall surrounding a cell membrane, inside of which lies the unbound nuclear matter and other material. Some cells are surrounded with a gelatinous capsule. The jellylike cells are almost transparent, so that it is necessary to stain them with a dye to see them clearly.
Most bacteria reproduce by dividing in the middle to form two cells.
After these cells reach maturity, they in turn divide to form four. In some bacteria, such division may occur as often as every 15 minutes. Thus billions of bacteria may be formed from a single bacterium in 24 hours. Others divide only every 16 hours. Where Bacteria Are Found Bacteria are found in more varied habitats and environments than any other living thing.