Introduction to Lab 6: Ex. Protozoa

This lab exercise introduces a group of microorganisms that are called the Protozoa (proto – primitive; zoa – animal). Characteristics of Protozoa are: -unicellular (one-celled) organisms, -aquatic habitats -Eukaryotic - lack a cell wall, -may have specific structures to help in movement: (pseudopodia, flagella, cilia); -aerobic, -holozoic nutrition (ingest food particles). -some are parasitic and cause diseases in humans and animals.

Protozoa are classified into different groups based on the presence and type of locomotory organelle they possess: Sarcodina - pseudopodia (false feet – cytoplasmic outflowings that help the organism move and to obtain food); Mastigophora – have whip-like structures called flagella, move by undulations); Ciliophora – have short hair-like structures distributed over the surface to help in locomotion. Organisms will be studied by making wet mounts. Methyl cellulose (protoslo) will be added to slow down highly motile organisms.

Specific organisms to be studied in lab: Amoeba proteus: (wet mount) Amorphous structure changing shape due to formation of pseudopodia

Euglena: (wet mount) Elongated shape with flagella protruding out of one end; green due to presence of chloroplast (able to photosynthesize)

Trypanosoma: (stained slide) Elongated with a single flagella out of one end. Causes Sleeping sickness in humans – transmitted to humans by the bite of vector – the tse tse fly. Infection found in the blood and affects the nervous system resulting in loss of muscle control and gives the appearance of sleeping. Found in Africa and South America

Paramecium: (wet mount) Slipper shaped cell with many cilia distributed over the entire surface of the organism.