Microbiology – Chapter 4: Introduction to Eukaryotic Cells

Vocabulary flashcards covering key terms from Chapter 4—including eukaryotic evolution, cellular processes, parasitic worms, fungal diseases, and major groups of protists—to help review microbiology concepts for the exam.

Endosymbiotic Theory

Explanation that eukaryotic organelles (mitochondria, chloroplasts) originated from symbiotic prokaryotes engulfed by an ancestral cell.

Mitochondria (Origin)

Organelles thought to have arisen from engulfed non-photosynthetic prokaryotes according to endosymbiotic theory.

Chloroplast (Origin)

Photosynthetic organelle believed to have evolved from an engulfed cyanobacterium.

Circular DNA (Organelle Evidence)

Mitochondria and chloroplasts possess this bacterial-like genome, supporting endosymbiotic theory.

70S Ribosomes

Prokaryote-style ribosomes found in mitochondria and chloroplasts, not 80S like rest of the eukaryotic cell.

Binary Fission (Organelle)

Bacterial-type replication process used by mitochondria and chloroplasts to divide.

Eukaryotic Cell

Cell type with membrane-bound nucleus, multiple linear chromosomes, and diverse organelles; larger and more complex than prokaryotes.

Membrane-Bound Organelle

Intracellular structure surrounded by lipid bilayer (e.g., nucleus, mitochondrion, ER, chloroplast).

Mitosis

Asexual eukaryotic cell division yielding two genetically identical diploid daughter cells.

Meiosis

Sexual eukaryotic division consisting of two sequential divisions that produce four genetically unique haploid gametes.

Crossing Over

Exchange of homologous chromosome segments during meiosis that increases genetic diversity.

Gamete

Haploid reproductive cell produced by meiosis (e.g., sperm or egg).

Binary Fission

Asexual division used by prokaryotes and some organelles; produces two identical cells.

Endocytosis

Bulk import mechanism where the plasma membrane invaginates to internalize substances in vesicles.

Exocytosis

Process by which vesicles fuse with the plasma membrane to release contents outside the cell.

Pinocytosis

“Cell drinking” form of endocytosis that non-selectively uptakes small volumes of extracellular fluid.

Phagocytosis

Endocytic process where a cell engulfs large particles or microbes into a phagosome.

Phagolysosome

Fusion product of a phagosome with a lysosome; site of microbial destruction by hydrolytic enzymes.

Receptor-Mediated Endocytosis

Highly specific uptake wherein ligands bind surface receptors triggering clathrin-coated vesicle formation.

Clathrin

Protein that coats inward-forming vesicles during receptor-mediated endocytosis.

Acidic Endosome

Intracellular vesicle with lowered pH where ligands dissociate from receptors after endocytosis.

Animal Kingdom

Eukaryotic multicellular organisms lacking photosynthesis; includes parasitic worms (helminths) and arthropods.

Helminth

Parasitic worm such as roundworms, tapeworms, or flukes; often have complex life cycles.

Tapeworm (Cestode)

Segmented flatworm that can reach meters in length; hermaphroditic; acquired by ingesting larval cysts in undercooked meat or fish.

Fluke (Trematode)

Non-segmented leaf-shaped flatworm; includes liver, lung, and blood flukes; often require snails as intermediate hosts.

Roundworm (Nematode)

Cylindrical, non-segmented worm; sexes separate; transmitted by eggs/larvae via fecal–oral route or skin penetration.

Hookworm

Nematode whose larvae penetrate skin, migrate to lungs, then intestines; can cause cutaneous larva migrans.

Trichinella spiralis

Nematode responsible for trichinosis; larvae encyst in muscle after ingestion of undercooked pork or game.

Mycosis

Disease caused by a fungus.

Opportunistic Fungus

Fungal organism that mainly causes disease in immunocompromised or microbiota-disrupted hosts (e.g., Candida species).

True Fungal Pathogen

Fungus capable of infecting healthy hosts (e.g., Histoplasma capsulatum, Coccidioides spp.).

Dermatophyte

True pathogenic fungus that infects keratinized tissues (skin, hair, nails); causes tinea (ringworm) infections.

Mycotoxin

Toxic secondary metabolite produced by fungi; includes ergot toxin from Claviceps purpurea.

Ergot Toxin

Potent neurotoxin causing seizures, psychosis, and vasoconstriction, produced by Claviceps purpurea on grains.

Protist

Broad group of eukaryotes that are not plants, animals, or fungi; variable forms, nutrition, and reproduction.

Protozoan

Unicellular, usually motile, non-photosynthetic protist; classified by locomotion type.

Amoeboid Protozoan

Protozoan that moves via pseudopods (e.g., Entamoeba histolytica, Naegleria fowleri).

Flagellated Protozoan

Protozoan possessing one or more flagella for motility (e.g., Giardia lamblia, Trypanosoma spp.).

Trypanosoma cruzi

Flagellated protozoan causing Chagas disease, transmitted by Triatomine “kissing” bugs.

Ciliated Protozoan

Protozoan using numerous cilia for movement; Balantidium coli is the only human pathogen in this group.

Spore-Forming Protozoan (Apicomplexan)

Obligate intracellular parasite that glides, lacking flagella/cilia; complex life cycle with merogony, gamogony, sporogony.

Merogony

Asexual replication phase of apicomplexans producing numerous merozoites.

Gamogony

Sexual phase of apicomplexans that forms gametes from some merozoites.

Sporogony

Phase where zygote forms spores containing infectious sporozoites in apicomplexans.

Toxoplasma gondii

Apicomplexan parasite causing toxoplasmosis; often transmitted via cat feces or undercooked meat.

Plasmodium spp.

Apicomplexan parasites that cause malaria in humans, transmitted by Anopheles mosquitoes.

Cryptosporidium

Spore-forming protozoan causing diarrheal disease; resistant to chlorine and spread via water.

Microsporidia

Group of spore-forming obligate intracellular fungi-like parasites; cause microsporidiosis, especially in immunocompromised.