Environmental Engineering Reference
In-Depth Information
Capsule
Inclusions
Nuclear Material
Cell Membrane
Cytoplasm
Mesosome
Ribosomes
Cell Wall
Flagellum
Figure 6.2
Bacterial cell.
Structure of the bacterial Cell
The structural form and various components of the bacterial cell are prob-
ably best understood by referring to the simplified diagram of a rod-form
bacterium shown in Figure 6.2 . When studying Figure 6.2 , keep in mind that
cells of different species may differ greatly, both in structure and chemical
composition; for this reason, no typical bacterium exists. Figure 6.2 shows a
generalized bacterium used for the discussion that follows; however, not all
bacteria have all of the features shown in the figure, and some bacteria have
structures not shown in the figure.
Capsules
Bacterial capsules (see Figure 6.2 ) are organized accumulations of gelatinous
material on cell walls, in contrast to slime layers (a water secretion that adheres
loosely to the cell wall and commonly diffuses into the cell), which are unor-
ganized accumulations of similar material. Macrocapsules are usually thick
enough to be seen under an ordinary light microscope, but thinner capsules
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