● Bacterial cells may be `color{violet}"motile or non-motile"`.

● If motile, they have `color{violet}"thin filamentous extensions"` from their cell wall called `color{Brown}"flagella"`.

● Bacteria show a `color{violet}"range"` in the `color{violet}"number and arrangement"` of flagella.

● `color{violet}"Bacterial flagellum"` is composed of three parts – `color{Brown}"filament, hook"` and `color{Brown}"basal body"`.

● The `color{violet}"filament"` is the `color{violet}"longest portion"` and extends from the cell surface to the outside.

● Besides flagella, `color{Brown}"Pili and Fimbriae"` are also `color{violet}"surface structures"` of the bacteria but `color{violet}"do not play"` a role in `color{violet}"motility"`.

● The `color{Brown}"pili"` are `color{violet}"elongated tubular structures"` made of a `color{violet}"special protein"`.

● The `color{Brown}"fimbriae"` are `color{violet}"small bristle like fibres"` sprouting out of the cell.

● In some bacteria, they are known to `color{violet}"help attach the bacteria"` to rocks in streams and also to the `color{violet}"host tissues"`.

● In `color{violet}"prokaryotes ribosomes"` are associated with the `color{violet}"plasma membrane"` of the cell.

● They are about `color{violet}"15 nm by 20 nm"` in size and are made of two subunits - `color{Brown}"50S and 30S units"` which when present together form `color{Brown}"70S prokaryotic ribosomes"`.

● `color{violet}"Ribosomes"` are the site of `color{violet}"protein synthesis"`.

● `color{violet}"Several ribosomes"` may attach to a `color{violet}"single mRNA"` and form a chain called `color{Brown}"polyribosomes or polysome"`.

● The `color{violet}"ribosomes of a polysome"` translate the `color{violet}"mRNA into proteins"`.

● `color{violet}"Reserve material"` in prokaryotic cells are `color{violet}"stored in the cytoplasm"` in the form of `color{Brown}"inclusion bodies"`.

● These are `color{violet}"not bounded"` by any membrane system and `color{violet}"lie free in the cytoplasm"`, e.g., `color{Brown}"phosphate granule"`s, `color{Brown}"cyanophycean granules"` and `color{Brown}"glycogen granules"`.

● `color{Brown}"Gas vacuoles"` are found in `color{violet}"blue green"` and `color{violet}"purple and green"` photosynthetic bacteria.