1. Anatomy of
Prokaryotic Cells
Dyzza Lei L. Albarico
Julian Philip A. Soriano
Shaina Mavreen D. Villaroza

2. What are Prokaryotic Cells?
Prokaryotes are single-celled organisms that are
the earliest and most primitive forms of life on
earth.
They have no true nucleus as the DNA is not
contained within a membrane or separated from
the rest of the cell

4. Prokaryotes do not have a
nucleus, mitochondria, or any other membrane-
bound organelles. In other words, neither their
DNA nor any of their other sites of metabolic
activity are collected together in a discrete
membrane-enclosed area.
They have a single, circular chromosome.
They have cell walls containing peptidoglycan
Their DNA is not associated with Histones.

5. Cell Structure
 Capsule - Found in some bacterial cells, this
additional outer covering protects the cell
when it is engulfed by other organisms, assists
in retaining moisture, and helps the cell
adhere to surfaces and nutrients.

Cell Wall - Outer covering of most cells that
protects the bacterial cell and gives it shape.

Cytoplasm - A gel-like substance composed
mainly of water that also contains
enzymes, salts, cell components, and various
organic molecules.

6. Cell Structure
 Cell Membrane or Plasma
Membrane - Surrounds the cell's
cytoplasm and regulates the flow of
substances in and out of the cell.
 Pili - Hair-like structures on the
surface of the cell that attach to other
bacterial cells. Shorter pili called
fimbriae help bacteria attach to
surfaces.

7. Cell Structure
 Flagella - Long, whip-like protrusion
that aids in cellular locomotion.
 Ribosomes - Cell structures
responsible for protein production.

Plasmids - Gene carrying, circular
DNA structures that are not involved in
reproduction.
 Nucleiod Region - Area of the
cytoplasm.

8. Cell Structure

9. Cell Shape
 Prokaryotes appear in 3 basic shapes:
1. Coccus – Spherical shaped
(plural,Cocci)
2. Bacillus – Rod shaped (plural, Bacilli)
3. Spirillium – Spiral known

10. Coccus
 The cocci are spherical or oval bacteria
having one of several distinct arrangements
based on their planes of division.
a. Division in one plane produces either
a diplococcus or streptococcus
arrangement.
1. diplococcus: cocci arranged in pairs
2.streptococcus: cocci arranged in chains
b. Division in two planes produces
a tetrad arrangement.
1.a tetrad: cocci arranged in squares of 4

11. Coccus
c. Division in three planes produces
a sarcina arrangement.
1.sarcina: cocci in arranged cubes of 8
d. Division in random planes produces
a staphylococcus arrangement.
1.staphylococcus: cocci arranged in
irregular, often grape-like clusters
 An average coccus is about 0.5-1.0 micrometer
(µm) in diameter.
 (A micrometer equals 1/1,000,000 of a meter.)

12. Coccus Shape

13. Spirillum
 Spirals come in one of
three forms, a vibrio, a spirillum, or
a spirochete.
a) vibrio: a curved or comma-shaped rod
b) spirillum: a thick, rigid spiral
c) spirochete: a thin, flexible spiral
 Spirals range in size from 1 µm to over
100 µm in length.

14. Bacillus
 Bacilli are rod-shaped bacteria. Bacilli all
divide in one plane producing
a bacillus, streptobacillus, or coccobacillus ar
rangement.
a) bacillus: single bacilli
b) streptobacillus: bacilli arranged in chains
c) coccobacillus: oval and similar to a coccus
 An average bacillus is 0.5-1.0 µm wide by
1.0-4.0 µm long.

15. Bacillus Shape

16. Example:

18. Staining Techniques
 Simple Stains
◦ Differential Stains
1. Gram Staining
2. Acid-fast Stain
◦ Special Stains
1. Endospore Staining
2.Flagella Staining
3.Capsule Staining

19. Simple Staining
 Staining can be performed with basic
dyes such as crystal violet or
methylene blue, positively charged
dyes that are attracted to the
negatively charged materials of the
microbial cytoplasm.

20. Differential Staining
 Gram Staining
This differential technique separates bacteria into
two groups, Gram-positive bacteria and Gram-negative
bacteria.
Crystal violet is first applied, followed by the
mordant iodine, which fixes the stain .Then the slide is
washed with alcohol, and the Gram-positive bacteria
retain the crystal-violet iodine stain; however, the Gram-
negative bacteria lose the stain.
The Gram-negative bacteria subsequently stain
with the safranin dye, the counterstain, used next.
These bacteria appear red under the oil-immersion
lens, while Gram-positive bacteria appear blue or
purple, reflecting the crystal violet retained during the
washing step.

21. Figure 1. The Gram stain
procedure used for differentiating
bacteria into two groups.

22. •Acid Fast Stain
This technique differentiates species
of Mycobacterium from other bacteria.
Heat or a lipid solvent is used to carry the first
stain, carbolfuchsin, into the cells. Then the cells are
washed with a dilute acid-alcohol
solution. Mycobacterium species resist the effect of the
acid-alcohol and retain the carbolfuchsin stain (bright
red).
Other bacteria lose the stain and take on the
subsequent methylene blue stain (blue). Thus, the acid-
fast bacteria appear bright red, while the nonacid-fast
bacteria appear blue when observed under oil-
immersion microscopy.

23. Special Staining
 Negative Staining for Capsule
Capsule staining uses a mixture of the bacteria
in a solution containing a fine colloidal
suspension of colored particles to provide a dark
background and then stain the bacteria with a
simple stain such as safranin.

24. Example of Negative Staining

25. Endospore Staining
◦ An endospore is a special resistant
dormant structure formed within a cell that
protects a bacterium from adverse
environmental conditions. Endospores
cannot be stained by ordinary methods
such as simple stains and gram staining.
Malachite green the primary stain is
applied to a heat fixed smear and heated
to steaming for about 5 min. Then the
perparation is washed for about 3o sec.
with water to remove the malachite green
from all the cells parts except for the

26. Example of Endospore
Staining

27. Flagella Staining
A tedious and delicate staining
procedure uses a mordant and the stain
carbolfuchsin to build up the diameters of
the flagella until they become visible
under the light microscope

28. Example of Flagella Staining