Protists and Fungi

Definition: A diverse group of eukaryotic organisms. It includes unicellular, colonial, and simple multicellular organisms that are not plants, animals, or fungi.

Groups:

1. Animal-like (Protozoa): Heterotrophs. e.g., Amoeba, Plasmodium.
2. Plant-like (Algae): Autotrophs. e.g., Euglena, Kelp.
3. Fungus-like: Absorptive heterotrophs. e.g., Slime molds.

• Amoebae: Move by Pseudopodia (false feet). e.g., Entamoeba histolytica (causes Dysentery).
• Zooflagellates: Move by Flagella. e.g., Trypanosoma (causes Sleeping Sickness).
• Ciliates: Move by Cilia. e.g., Paramecium (has 2 nuclei: Macronucleus & Micronucleus).
• Sporozoans: Parasitic, non-motile, spore-formers. e.g., Plasmodium.

Involves two hosts: Man (Intermediate) and Mosquito (Definitive).

1. In Man (Asexual): Sporozoites injected by mosquito → Liver (Schizogony) → Merozoites released → Enter RBCs → Trophozoites (Ring stage) → Rupture RBCs (Fever/Chills) → Gametocytes formed.
2. In Mosquito (Sexual): Gametocytes ingested → Gametes fuse in stomach → Zygote → Ookinete → Oocyst → Sporogony → Sporozoites migrate to salivary glands.

• Euglenoids: e.g., Euglena. Have flagella, chloroplasts, but no cell wall (Pellicle instead). Mixotrophic.
• Dinoflagellates: 2 flagella. Cause 'Red Tides' (blooms). e.g., Gonyaulax.
• Diatoms: Silica shells (frustules). Major producers in oceans.
• Green Algae (Chlorophyta): Ancestors of plants. e.g., Chlorella, Spirogyra.
• Brown Algae (Phaeophyta): Largest protists (Kelps). Marine. e.g., Fucus.
• Red Algae (Rhodophyta): Marine. Source of Agar. e.g., Polysiphonia.

Characteristics: Eukaryotic, Non-motile, Heterotrophic (Absorptive). Cell wall made of Chitin.

Structure: Body is called Mycelium, made of thread-like filaments called Hyphae. Hyphae can be Septate (cross-walls) or Coenocytic (non-septate/multinucleate).

• Zygomycota (Zygomycetes): Conjugating fungi. Coenocytic hyphae. Sexual spore: Zygospore. e.g., Rhizopus (Black Bread Mold).
• Ascomycota (Sac Fungi): Largest group. Septate hyphae. Sexual spore: Ascospores produced inside an Ascus. e.g., Yeasts (Unicellular), Penicillium, Truffles.
• Basidiomycota (Club Fungi): Septate hyphae. Sexual spore: Basidiospores produced on a Basidium. e.g., Mushrooms, Rusts (Puccinia), Smuts (Ustilago).
• Deuteromycota (Imperfect Fungi): Sexual reproduction absent or unknown. Reproduce asexually by Conidia. e.g., Alternaria, Fusarium.

• Beneficial: Decomposers (recycle nutrients), Food (Mushrooms, Morels), Fermentation (Yeast in baking/brewing), Antibiotics (Penicillin from Penicillium).
• Harmful: Plant diseases (Rusts, Smuts, Powdery mildew), Animal diseases (Ringworm, Athlete's foot, Candidiasis), Mycotoxins (Aflatoxin).