PROTOZOA PHYLA
General characteristics:
 Single-celled or unicellular organisms; some live in colonies;
 Size = microscopic (3 to 1,000 microns).
 No germ layers, tissues, or organs.
 Specialized intracellular "organelles" are present.
 Locomotion by pseudopodia, flagella, or cilia.
 Symmetry = all types (bilateral, radial, spherical, or asymmetrical).
 Free living, commensal, parasitic, or mutualistic.
 Mostly naked, but few have simple protective exoskeletons.
 Reproduction: asexual = longitudinal and transverse binary fission, budding.
List of Phyla:
 Amoeba-like organisms (e.g., Amoeba)
 Phylum Euglenozoa
o Subphylum Euglenida (e.g., Euglena)
o Subphylum Kinetoplasta (e.g., Trypanosoma)
 Phylum Chlorophyta (e.g., Volvox)
 Phylum Apicomplexa (e.g., Plasmodium)
 Phylum Ciliophora (e.g., Paramecium)
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1. AMOEBA
Special features of the Amoeba:
 Amoebas are single-celled organisms.
 Flexible outer Membrane.
 Asymmetrical body.
 Continually change shape in movement.
 They spend most of their time attached to the bottom or to plants.
 The amoeba is a tiny, one-celled organism. You need a microscope to see most amoebas,
the largest are only about 1 mm across.
 Live in fresh water, salt water (ocean), in wet soil, in animals (including people) and
other organisms (they’re parasites!).
Anatomy
An amoeba consists of a single cell surrounded by a porous cell membrane. The amoeba
"breathes" using this membrane - oxygen gas from the water passes in to the amoeba through the
cell membrane and carbon dioxide gas leaves through it. Jelly-like cytoplasm fills most of the
cell. A large nucleus within the amoeba controls its growth and reproduction.
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Structure of Amoeba
Part of the amoeba:
 Nucleus
 Food vacuole
 Contractile vacuole
 Pseudopod
 Cytoplasm
 Cell Membrane
Cell membrane is semi-permeable. Cytoplasm divided up into endoplasm and ectoplasm and the
endoplasm is fluid-like. It has a grainy appearance due to the presence of food vacuoles and
waste materials. Ectoplasm can become soft in places to allow the development of pseudopodia.
Pseudopods are referred to as ‘false feet’ as they are produced at any point on the body and have
no fixed position. Pseudopodia extend in the direction Amoeba wishes to move.
Process of feeding
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To eat, the amoeba stretches out the pseudopod, surrounds a piece of food, and pulls it into the
rest of the amoeba's body. Some amoebas are parasites and amoebas eat algae, bacteria, other
protozoans, and tiny particles of dead plant or animal matter.
Phagocytosis: Amoeba feeds by surrounding its prey with pseudopodia and secreting digestive
enzymes into the vacuole created.
Steps in the Phagocytosis process:
 Forming of a psueudopod to engulf food.
 Part of membrane pinches off.
 Creates a food vacuole.
 Fuses with enzyme-filled lysosome.
 Creates digestion vacuole.
 Excretes waste.
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Movement: The psuedopod is used to help the amoeba move, and also to eat. This part of the
amoeba's body can stretch out and pull itself with.
 Temporary cytoplasmic projections.
 Cytoplasm flows into projection until entire cell has moved.
 Also used to capture food through Phagocytosis-surround food.
 This type of movement is called “cytoplasmic streaming.
Reproduction:
Amoebas reproduce (make more amoebas) by a process called binary fission. This means that
one amoeba can split in half and make two identical new amoebas. This is asexual reproduction.
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Trypanosoma
General characteristic of the Protozoa are :
1- Unicellular ( consist of one cell ) this cell performs all phsiological function ( activities ) of
life such as locomation , reproduction , respiration , ingestion , digestion and excretion .
2- They vary in size and shape some are visible while others require high magnification ( by
microscope ) .
3- The majority of protozoa are free living but some are parasitic.
4- Both sexual and asexual reproduction occur in protozoa (the majority of protozoa reproduce
by asexual reproduction) .
Class: Mastigophora .
Order: kinetoplastida
Family: trypanosomatidae
Genus:trypanosoma
Disease:typansomiasis.
1- T.gambiense : cause African sleeping sickness in human.
2- T .crusi : cause chagas disease (American trypanosomiasis) in human and dog.
3- T .evansi : cause surra disease of all domestic animals.
4- T. equiperdum : cause Dourine disease in horse & donkey.
Transmission or intermediate hosts (vector):-
T .brucei
T .gambiense
tse tse fly (glossina).
T .rhodesiense
T .evansi
tabanus (horse fly).
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T .cruzi
kissing bug (panstrongylus).
T. equiperdum transmition by coitus .
Trypanosoma are present in blood , lymph , lymphnodes and cerebrospinal fluid .trypanosoma is
multiply by longitudinal binary fission.
1-trypanosmes is an elongated , spindle-shape cell with a single nucleus near the middle of
parasite.
2-it has kinetoplast.
3-it has undulating membrane.
4-possess a slender-single flagella at the anterior end.
5-flagellum serve as organ of attachment and locomotion.
6-there are four stages in life cycle :A –trypomastigote:- postnuclear kinetoplast , flagellum start from anterior end with undulating
membrane , found in vertebrate and insects.
B –epimastigote:- kinetoplast anterior to nucleus flagellum emerging from the body and
continuing to the anterior end with short undulating membrane.
C –promastigote:- kinetoplast at the anterior end. Flagellum emerging from anterior end of the
body . there is no undulating membrane.
D–amastigote:- spherical or oval in shape without undulating membrane . flagellum not extend
from outside the membrane , start from the kinetoplast.
Diagnosis:1.blood smear , trypanosomes found in blood.
2.Lymph smear .
3.Serological test.
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Trypomastigote
Epimastigote
Promastigote
Amastigote
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