2. 1- Know the definition of protozoa
2- Identify the general characteristics of protozoa
3- Identify the reproduction of protozoa
4- Identify the structure of the protozoa
5- Learn about the movement of protozoa
6- Identify the classification of protozoa
7- Identify the characteristics of protozoa
diagnosis
8- Identify the modes of transmission of protozoa
9- Differentiation between trophozoite and cyst
10- Get to know Protozoan Parasites of Humans
Objectives
3. Protozoa
Protozoa are one-celled animals found worldwide in most habitats.
Most species are free living, but all higher animals are infected with
one or more species of protozoa.There are about 45,000 protozoan
species; around 8000 are parasitic, and around 25 species are
important to humans.
4. ● Eukaryotic
● cell is much larger and more complex than prokaryotic cell and contains
a variety of organelles (Golgi apparatus, mitochondria, ribosomes, etc).
● Unicellular
● They lack a cell wall
● Vegetative form is a trophozoite
General Characteristics of Protozoa
5. Reproduction in Protozoa
Protozoa mostly reproduce asexually by binary fission
or multiple fission. Many protozoa also exchange
genetic material by sexual means (typically, through
conjugation)
6. Protozoa are microscopic unicellular eukaryotes that have a relatively
complex internal structure and carry out complex metabolic activities.
Some protozoa have structures for propulsion or other types of movement.
The Structure of Protozoa
9. 03
02
(Ciliata) The ciliates are propelled by rows of cilia
that beat with a synchronized wavelike motion.
01
Protozoa is Classified into Four Subdivisions
According to The Methods of Locomotion.
(Sarcodina) The amoebae move by means of
pseudopodia.
(Mastigophora) The flagellates typically move
by long, whiplike flagellae.
04
(Sporozoa) The sporozoans lack specialized
organelles of motility.
10. Diagnostic Features
• Nuclear structure - important in species differentiation.
• Size - helpful in identifying organisms; must have
calibrated objectives on the microscope in order to
measure accurately.
• Cytoplasmic inclusions - chromatoid bars (coalesced RNA)
food vacuoles containing bacteria, yeast
• Appearance of cytoplasm - smooth & clean or vacuolated.
• Type of motility - directional or non-directional; sluggish
or fast
12. Protozoa that enter the body via
ingestion have twomorphological
forms
Trophozoite
- the motile vegetative stage;
multiplies via binary fission;
colonizes host
Cyst
- the inactive, non-motile,
infective stage; survives
the environment due to the
presence of a cyst wall. Cysts
do not multiply, however,
some organisms divide within
the cyst wall.
13. Flagellates
• Protozoa that possess at least one flagellum
• Number and arrangement of flagella important
to determining the species
• The flagellates include members of the genera
Trypanosoma, Leishmania, Giardi, and
Trichomonas
• Protozoa that use cilia in their trophozoite
stage
• Only ciliate known to cause disease in
humans
• Commonly found in animal intestinal tracts
• Humans infected by food or water
contaminated with feces containing cysts
Protozoan Parasites of Humans
Amoebae
• Protozoa with no truly defined shape
• Move and acquire food through the
use of pseudopodia
• Found in water sources throughout
the world
• Few cause disease
Ciliates
