Many are pathogenic and so give the good guys, like the photosynthesizers, a bad name. Splendid Metabolic Diversity Photoautotrophs synthesize their own organic compounds using sunlight as the energy source and carbon dioxide as the carbon source. Chemoautotrophs use carbon dioxide and produce organic compounds using the energy in simple inorganic substances. Chemoheterotrophs include parasitic types that draw nutrition from living hosts and saprobic types that obtain nutrition from products, wastes, or remains of other organisms. Typically, the length or width of bacteria falls between 1 - 10 nm.
Metabolic reactions take place in the cytoplasm or at the plasma membrane.
Proteins are assembled on floating ribosomes. Nearly all bacteria have a cell wall, usually containing a tough mesh of peptidoglycan, peptides cross-linked with polysaccharides. Cell walls of Gram-positive bacteria retain a deep purple stain. Gram-negative bacteria lose the purple color when washed with alcohol and stain pink with a counterstain. Exterior to the cell wall is the glycocalyx, a jellylike capsule that helps bacterial cells attach to a substrate or deter the host's infection-fighting cells.