Chapter 5: Eukaryotic Cells and Microorganisms

Vocabulary flashcards covering key terms related to eukaryotic cells and their microorganisms from the lecture notes.

Endosymbiotic theory

Eukaryotic cells arose when one prokaryotic cell engulfed another living inside it, and the two evolved together until they became a single organism.

Eukaryotes

Organisms with membrane-bound organelles and a nucleus; thought to arise via endosymbiosis.

Mitochondrion

Energy-producing organelle in most eukaryotic cells; site of cellular respiration.

Nucleus

Organelle that houses the cell’s DNA; surrounded by a nuclear membrane.

Ribosome

Small particle where protein synthesis occurs; made of RNA and proteins.

Endoplasmic reticulum

Membrane network involved in protein (rough ER with ribosomes) and lipid synthesis (smooth ER).

Golgi apparatus

Organelle that modifies, sorts, and ships proteins and lipids to their destinations.

Cytoplasm

Semifluid interior of the cell that holds organelles and hosts many metabolic activities.

Cell wall

Rigid layer outside the cytoplasmic membrane; present in fungi and some algae.

Fungi

Majority are harmless heterotrophic saprobes; some are parasites; cause mycoses; widespread.

Candidiasis (Candida albicans)

Fungal infection including vaginal yeast infections and oral thrush.

Aspergillosis (Aspergillus)

Respiratory infection and allergy caused by Aspergillus spores.

Blastomycosis (Blastomyces)

Respiratory infection from Blastomyces; associated with Ohio or Mississippi River valleys.

Coccidioidomycosis / Valley Fever (Coccidioides)

Respiratory infection with flu-like symptoms and rash from Coccidioides spores (SW US).

Histoplasmosis (Histoplasma)

Respiratory infection from soil with bird or bat droppings.

Algae

Photosynthetic organisms; free-living in fresh and marine water; basis of aquatic food webs; produce much of Earth's O2.

Dinoflagellates

Algae that can produce neurotoxins, cause red tides, and lead to food poisoning via toxins.

Red tides

Algal blooms (often by dinoflagellates) producing toxins that discolor water and can affect health/ecosystems.

Paralytic shellfish poisoning (PSP)

Neurotoxic effect from shellfish contaminated with dinoflagellate toxins; can cause severe illness or death.

Protozoa

Single‑celled eukaryotes with life cycles that include trophozoite and cyst stages; reproduce asexually or sexually.

Trophozoite

Motile, feeding stage of protozoa; active form.

Cyst

Dormant resting stage formed by some protozoa under unfavorable conditions.

Encystment

Process by which protozoa form cysts to survive adverse conditions.

Excystment

Reactivation of trophozoite from a cyst.

Conjugation

Sexual reproduction in some protozoa involving genetic material exchange.

Malaria (Plasmodium)

Protozoan disease transmitted by mosquitoes; RBC involvement is central to its life cycle.

Plasmodium

Genus of protozoan parasites that cause malaria.

Ascaris lumbricoides

Common roundworm infection of the intestine; linked to poor sanitation; symptoms vary with worm load.

Hookworm (Ancylostoma spp.)

Soil‑transmitted roundworms; larvae penetrate skin; can cause anemia; widespread in warm regions.

Trematodes (Flukes)

Flattened, ovoid flatworms with sucking mouthparts; cause foodborne trematodiases; prevalent in certain regions.

Cestodes (Tapeworms)

Eggs form larval cysts in tissues; adults live in the intestine; transmission via contaminated food or water.

Helminths

Parasitic worms including flatworms and roundworms; commonly inhabit soil and water.

Prevention of Helminth-Associated Disease

Prevent fecal contamination of soil and water; proper sewage and latrine use; avoid infested water; cook or freeze food to kill eggs.