Here , is the description of morphology of bacteria .

1. - Sonal Maurya
- @microbiology-edu

2. MORPHOLOGY : It is the study of external
character of bacteria i.e., size , shape , arrangement of
the bacteria.
■ Explanation :
1. Size of bacteria :-
 Size of bacteria is less than 3mm .
 Bacteria’s may be spherical , cylindrical or spiral .
 Bacteria’s are visible under the compound microscope .
 Bacteria’s size measurement are done by micrometry or electron microscopic
micrometry.
2. Shape of bacteria :-
 They depend on the rigidity of the cell wall .
3. Arrangement of bacteria :-
 This means that whether the bacteria exist in the single form or in the colony/
grouping form.

3. ■ There are some of the units which are used for the measurement of
the bacteria:-
• Micrometer(mm)
• Nanometer (nm)
• Millimicron (uu)
• Angstrom (A°)

4. 1. Spherical bacteria ( round or cocci shaped )
2. Rod shaped bacteria ( rod / bacilli shaped )
3. Spiral shaped (spiral / helical structure )

5. Staphylococcus
Coccus
Diplococcus
streptococcus
SPHERICAL :-
(Round or cocci ) ■ They are round shaped bacteria.
■ They don’t have flagella , so they cannot move and they
have to depend on the living organism or environmental
condition for their movement from one place to another.
■ The size ranges from 0.5 to 1.0 micrometer .
When two coccus shaped bacteria are joined together then
they are called Diplococcus .
when the coccus shaped bacteria are arranged
in a chain form , then they are called streptococcus .
When coccus shaped bacteria are arranged in a grouped or
clustered form then they are called staphylococcus .

6. Diplococcus
Bacillus
Rod shaped bacteria :-
(Bacilli or cylindrical)
* when the rod shaped bacteria are in single form
then they are called Bacillus .
* They have Flagella for their movement from
one place to another.
* Their size ranges from 0.5 to 1.0 micrometer
wide and 1.0 to 4.0 micrometer long .
when two rod shaped bacteria are
joined together , then they are called
Diplobacillus .
Diplobacillus

7. streptobacillus
when the rod shaped bacteria are
arranged in a chain form , then they
are called streptobacillus .
Note : The rod shaped bacteria doesn’t exist in a clustered
form .

8. Spirochetes
vibrio
spirilla
Spirilla :-
They don’t exist in the grouping form ,they only exist independently and in single form
only .
*They are rigid and spring type.
*No accurate size due to spiral form.
* They are comma shaped , and sometimes
they are having flagella also, for movement.
* They are incomplete spiral.
* They are like spirilla only they are flexible.