Key Terms
Plankton
Microorganisms that drift/float in water moved by currents.
Trophozoite
Feeding and growth stage; ingests bacteria and small particles. Cyst: dormant, encapsulated form; survives harsh environ
Excystment
Cyst reactivating when conditions improve.
Plasmalemma
Plasma membrane of a protist. Pellicle: protein bands just inside the membrane; adds rigidity.
Contractile vacuole
Organelle for osmotic regulation (removes excess water). Pseudopodia: cytoplasmic extensions used for movement and attac
Movement
Amoeboid — actin microfilaments produce pseudopodia; cytoplasm flows in.
Defining feature
Cilia on cell surface (used for locomotion AND feeding). Some forms are nonmotile.
Plasmodium
Causes malaria; transmitted by mosquito bite.
Example
Letharia vulpina (fruticose) — poisonous; once used to make arrowheads.
CDC prioritization criteria
Number of people infected, severity of illness, whether it can be treated or prevented.
Two major groups
1. Nematoda (roundworms) — unsegmented 2.
Four classes
Turbellaria, Monogenea, Trematoda, Cestoda. Medically important: Trematoda (flukes) and Cestoda (tapeworms).
Life cycle
1. Eggs consumed by intermediate host.
Hyphae
Filaments making up multicellular fungal bodies (molds).
Mycelium
Tangled network of hyphae; forms the thallus (body) of fleshy fungi.