Morphology means systematic study of external characters of bacteria.
Morphology of bacterial cell deals with study of
- Size of bacteria.
- Shape of bacteria.
- Arrangement of bacteria.
1. Size of bacteria.
- Size of bacterial cell is less than 3 micrometer.
- The bacteria are microscopic in nature and are visible only under compound microscope.
- These bacteria may be spherical,cylindrical or spiral in shape.
- Size of a spherical shape bacteria can be measures in diameter.
- Size of a cylindrical bacteria is measured by its length and width.
- In spiral shape bacteria length is measured but due to spiral form it is not exact.
- As we know all bacteria are microscopic in nature so their size is also measured under microscope.
- Size of bacteria is measured by using calibrated slide and calibrated occular compound microscope is used.
- The above method of measuring size is called as micrometry.
- The size of bacteria can also be measured by electron microscopic micrometry.
- Units of measurement used in bacteriology are
- Micron or micrometer.
- Nanometer (nm) or Millimicron.
- Angstrom (A°)
- The conversion are as follows
- 1 μm = 10-3 mm = 10-4cm = 10-6 meter1 nm = 10-3 μm = 10-6 mm1 A0 = 10-1 nm = 10-4 m =10-7 mm
- Size of spherical bacteria or cocci ranges from 0.5 to 3.0 μm.
- Size of cylindrical or rod shape bacteria ranges from 0.15 μm to 2.0 μm in width and 0.5 μ to 20 μ in lenght.
- The small size of bacteria have large surface area for entry of nutrients, water and exit of waste.