Eukaryotic Cells and Microorganisms Lecture Review

Comprehensive vocabulary flashcards covering the origins, structures, and classifications of eukaryotic microorganisms, including fungi, protozoa, and helminths.

Last Common Ancestor (LCA)

A primitive, likely large organism with loose boundaries and RNA genetic material from which bacteria, archaea, and eukarya evolved roughly $3$ to $4$ billion years ago.

Endosymbiosis

The theory that eukaryotic cells evolved when a pre-eukaryotic cell engulfed bacteria, which then stabilized to become mitochondria or chloroplasts.

Eukaryotic Flagella

Long, sheathed cylinders containing microtubules that are approximately $10$ times thicker and more structurally complex than their bacterial counterparts.

Cilia

Short, numerous locomotor structures similar to flagella, found primarily in a specific group of protozoa and certain animal cells.

Glycocalyx

An outermost layer of polysaccharides, appearing as a network of fibers, slime layer, or capsule, that functions in protection, adherence, and reception.

Chitin

A polysaccharide that forms the thick inner layer of fungal cell walls, providing rigid structural support.

Sterols

Lipid components in eukaryotic cell membranes that provide relative rigidity and stability, especially important for cells lacking a cell wall.

Nuclear Envelope

An external boundary of the nucleus consisting of two parallel membranes with regularly spaced pores for macromolecule transport.

Nucleolus

A dense region in the nucleoplasm where ribosomal RNA is synthesized and ribosomal subunits are collected.

Chromatin

The genetic material of the cell, composed of linear DNA molecules associated with histone proteins.

Rough Endoplasmic Reticulum (RER)

A series of membrane tunnels with attached ribosomes involved in protein synthesis and transport to the cell's exterior.

Smooth Endoplasmic Reticulum (SER)

A closed tubular network without ribosomes that functions in lipid synthesis and nutrient processing.

Golgi Apparatus

An organelle consisting of flattened sacs called cisternae where proteins are modified, packaged, and shipped via vesicles.

Lysosomes

Vesicles containing digestive enzymes used for intracellular digestion of food and protection against invading microbes.

Cristae

The inner folds of the mitochondrial membrane that house enzymes and electron carriers for aerobic respiration and $ATP$ production.

$70S$ Ribosomes

The size of ribosomes found specifically within mitochondria and chloroplasts, providing evidence of their bacterial origins.

$80S$ Ribosomes

The standard eukaryotic ribosome size, composed of a $60S$ large subunit and a $40S$ small subunit.

Actin Filaments

One of the three main fibers of the cytoskeleton, characterized as long, thin protein strands involved in cell movement.

Dimorphic

The ability of certain fungi to exist in either a yeast or hyphae form depending on growth conditions such as temperature.

Saprobe

An organism, such as many fungi, that obtains nutrients from the remnants of dead plants and animals.

Mycelium

The woven, intertwining mass of hyphae that constitutes the body or colony of a mold.

Sporangiospores

Asexual fungal spores formed by successive cleavages within a saclike head called a sporangium.

Trophozoite

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

Cyst

A dormant, resistant stage of protozoa that allows for survival in unfavorable environmental conditions and aids in disease transmission.

Nematodes

Roundworms characterized by an elongated, cylindrical, and unsegmented body plan.

Cestodes

A group of flatworms, commonly known as tapeworms, with thin, segmented body plans.

Intermediate Host

The host organism in which a helminth's larval stage develops.

Definitive Host

The final host in which a helminth reaches adulthood and undergoes sexual reproduction.