Protists are a diverse group of eukaryotic organisms including algae, protozoa, and slime and water molds. Some key protists discussed include Euglena, which is a phytoflagellated protozoan that contains chloroplasts and moves using a flagellum, Amoeba, which moves using pseudopodia and has two differentiated cytoplasmic regions, and Plasmodium, which is an apicomplexan parasite that causes malaria and has a complex lifecycle alternating between human and mosquito hosts.

1. Study of Animal like
Protists
Lecture-1 & 2

2. Key Concepts
• Protists are a diverse group of eukaryotic
organisms, most of which are microscopic.
• Contains
• Algae: “plant-like” protists..
• Protozoa: “animal-like” protists
• Slime & Water molds: fungal-like protists

3. What are Protists?
• Dumping ground” kingdom
• Eukaryotic
• Heterotrophic and/or autotrophic
• Single or multicellular
• Ancestors to animals, plants, fungi

4. Euglena- Phytoflagellated Protozoan
• One celled alga that moves with one flagellum
• About 50µm long
• Lives in fresh water
• Reproduces asexually
• Red eyespot near front end to find light (Stigma)
• Have chlorophyll and can make their own food (autotroph)
• Contains disk-shaped chloroplasts

5. Structure

6. Amoeba- Supergroup Amoebozoa
• Unicellular organism found in stagnant water
• Extremely variable size ranges from 2.3- 200,000µm
• They move with temporary cell extensions called pseudopodia
• Lobopodia
• Filopodia
• Reticulopodia
• Exopodia
• Cytoplasm differentiated into two parts;
• Outer ectoplast
• Inner endoplast containg food vacuoles

7. Amoeba….
• Examples; Arcella and Difflugia are freshwater amoebozoans
Difflugia Arcella

8. Entamoeba
• Entamoeba is a genus of Amoebozoa found as internal parasites or commensals of
animals.
• Have no flagella or centrioles, and lack mitochondria.
• Amoebiasis caused by Entamoeba histolytica
• Fourth most common protozoan infection in the world
• Entameoba histolytica causes amoebic dysentery (diarrhea) and can enter the liver, lungs,
and brain.
• The trophozoites are 20-30 µm in diameter and contain a vesicular nucleus.
• The cysts are spherical measuring 10-15 µm in diameter and have 4 nuclei.

10. Plasmodium
• Plasmodium is a genus of unicellular eukaryotes that are obligate parasites of vertebrates
and insects.
• They characteristically show the presence of apical complex.
• Apical complex consists of polar rings, rhoptries, micronemes, mitcochondrions,
microtubules and microspores
• Organs for locomotion
• They show slight amoeboid change of form

11. Plasmodium………..
• The parasite in their life cycle shows an alternation of generation accompanied by an
alternation of host
• Asexual cycle (Schizogony) takes place in erythrocytes in human host, sexual cycle
(Sporogony) takes place in mosquito
• Development of microgametes and macrogametes take place independently
• Each microgamont produces 8 microgametes on exflagellation.
• Sporozoites are naked with three layered wall

12. Plasmodium falciparum life cycle

13. Trypanosome- Zooflagallated Protozoan
• Name is derived from Greek word, trypano means “borer” and soma means “body”
• Unicellular flagellate protozoa
• Ranges in size from 14-33 micrometers
• Lack chloroplasts
• Heterotrophic
• Have single large mitochondrion that contain kinetoplasts
• Some are parasites
• Example; Trypanosoma brucei that caused African Sleeping Sickness

14. Morphology of Trypanosoma

15. Paramecium
• Unicellular, slipper-shaped
• Move by coordinated beating of many cilia
• Aquatic - mostly found in ponds and streams
• Have many specialized structures, including mouths, anal pores, contractile vacuoles, and
two nuclei (a large macronucleus and small micronuclei)
• Usually do not cause diseases in humans
• Feeding occurs in the funnel-shaped gullet (buccal cavity)
• Ingests organic detritus and other small organisms like bacteria and other protozoans

16. Reproduction in Paramecium
• Binary fission
• Conjugation; Form structure called conjugation tube to exchange genetic material
Binary fission Conjugation
Paramecium