b. Cell Wall Function – In many cases, the cell wall is very porous and does not regulate the
transport of substances into the cell. Two major functions of the cell wall are maintaining shape
and withstanding turgor pressure. Both are discussed below.
1.) Cell Shape - one fxn. of the cell wall is to confer shape on the bacterium; most bacteria fall
into one of these general groups. However, some bacteria have irregular shapes. Even bacteria of
the same kind or within the same culture sometimes vary in size and shape (especially in aging
cultures).
a.) cocci (singular - coccus) - spherical
b.) bacilli (singular - bacillus) - rod-shaped
c.) spirilli (singular - spirillum) - spiral-shaped
d.) vibrio - comma-shaped
In addition to these characteristic cell shapes, cells can also be found in distinctive groups of
cells: pairs, chains, tetrads (cubes), grape-like clusters, etc.
2.) Withstanding Turgor pressure – A cell's turgor pressure is the internal pressure from its
contents. Ordinarily, a bacterium is in a hypotonic solution (a more dilute solution that has less
8
transport of substances into the cell. Two major functions of the cell wall are maintaining shape
and withstanding turgor pressure. Both are discussed below.
1.) Cell Shape - one fxn. of the cell wall is to confer shape on the bacterium; most bacteria fall
into one of these general groups. However, some bacteria have irregular shapes. Even bacteria of
the same kind or within the same culture sometimes vary in size and shape (especially in aging
cultures).
a.) cocci (singular - coccus) - spherical
b.) bacilli (singular - bacillus) - rod-shaped
c.) spirilli (singular - spirillum) - spiral-shaped
d.) vibrio - comma-shaped
In addition to these characteristic cell shapes, cells can also be found in distinctive groups of
cells: pairs, chains, tetrads (cubes), grape-like clusters, etc.
2.) Withstanding Turgor pressure – A cell's turgor pressure is the internal pressure from its
contents. Ordinarily, a bacterium is in a hypotonic solution (a more dilute solution that has less
8
