Chapter 5: Eukaryotic Cells and Microorganisms Flashcards

Vocabulary flashcards focusing on the eukaryotic cell organelles, fungal structures and diseases, protists, and parasitic helminths covered in Chapter 5.

Glycocalyx

An outermost boundary of eukaryotic cells that comes into direct contact with the environment, composed of polysaccharides as a network of fibers, slime layer, or capsule.

Nucleolus

A specialized matrix region within the eukaryotic nucleus that serves as the site for ribosomal subunit synthesis.

Eukaryotic Ribosome

An $80\text{S}$ protein synthesizer composed of a $60\text{S}$ large subunit and a $40\text{S}$ small subunit.

Endomembrane System

The eukaryotic pathway for protein synthesis and transport, moving from the nucleus to the rough endoplasmic reticulum, transitional vesicles, Golgi apparatus, condensing vesicles, and out through secretory vesicles by exocytosis.

Chromatin

The material of eukaryotic chromosomes, consisting of long, linear DNA molecules bound to histone proteins.

Mycoses

Diseases caused by fungal infections in humans or animals, which typically occur through accidental exposure to soil, water, or dust.

Yeast

A microscopic fungal cell characterized by a round to oval shape that reproduces asexually by budding.

Hyphae

Long, threadlike cells that make up the body or filament structure of molds.

Pseudohypha

A chain of yeast cells formed when buds remain attached to one another in a line.

Mycelium

The woven, intertwining mass of hyphae that makes up the visible body or colony of a mold.

Dimorphic

The capacity of certain fungal species to take on either a yeast or hyphal form depending on growth conditions such as temperature.

Saprobes

Heterotrophic organisms that obtain their organic nutrients directly from dead plant and animal substrates.

Ergot Toxin

A potent neurotoxin produced by Claviceps purpurea that can lead to seizures, psychosis, nausea, vomiting, and death.

Aflatoxin

A toxic substance produced by molds such as Aspergillus on stored crops (grains, peanuts) that can cause liver cancer upon chronic long-term exposure.

Histoplasmosis

A community-acquired fungal respiratory disease caused by an environmental species that thrives in bird and bat droppings.

Coccidioidomycosis

Also called valley fever, a fungal disease caused by an environmental species in dust and soil of the southwestern United States that produces flu-like respiratory symptoms.

Protist

Any eukaryotic unicellular or colonial organism that lacks true tissues, historically encompassing algae and protozoa.

Plankton

A floating community of microscopic aquatic organisms, including algae, that forms the foundation of the aquatic food web and generates about $70\%$ of Earth's oxygen.

Trophozoite

The active, motile, feeding stage of a protozoan's life cycle that requires moisture and food to remain functional.

Protozoan Cyst

The dormant, resting stage of a protozoan encased in a protective wall, formed when conditions become unfavorable for survival.

Conjugation

A form of sexual genetic exchange that takes place between two protozoan cells.

Primary Amebic Meningoencephalitis (PAM)

A severe brain infection caused by free-living ameboid protozoa of the genera Naegleria and Acanthamoeba found in fresh water.

Nematodes

Roundworms characterized by a long, unsegmented, cylindrical body plan, such as Ascaris lumbricoides and Enterobius vermicularis.

Cestodes

Tapeworms; flatworms characterized by a long, ribbon-like, segmented body structure.

Trematodes

Flukes; flatworms characterized by a flat, unsegmented body plan.

O&P Testing

Ova and parasite testing of a stool sample to detect diagnostic microscopic stages of helminths and protozoa.

Intermediate Host

The host organism in which larval development of a parasitic worm occurs.

Definitive Host

The host organism in which adult parasite growth and sexual reproduction occur.

Enterobius vermicularis

The human pinworm, a nematode measuring $2\text{ to }12\,\text{mm}$ that causes self-limiting intestinal infection spread by the ingestion of fertile eggs.