Eukaryotic Cells and Microorganisms Flashcards

Comprehensive vocabulary flashcards covering the evolutionary history, structure, and classification of eukaryotic microorganisms, including fungi, protozoa, and helminths.

Last Common Ancestor (LCA)

A likely large organism with loose boundaries and RNA as genetic material from which bacteria, archaea, and eukarya all evolved.

Endosymbiosis

The process where pre-eukaryotic cells engulfed bacteria, which then evolved into mitochondria or chloroplasts.

Eukaryotic Flagella

Long, sheathed cylinders containing regularly spaced microtubules that are approximately 10 times thicker and more structurally complex than bacterial flagella.

Cilia

Short, numerous eukaryotic appendages similar to flagella in structure; found only in a single group of protozoa and certain animal cells.

Glycocalyx

The outermost layer composed of polysaccharides that functions in protection, adherence, and signal reception.

Chitin

A polysaccharide found in the thick inner layer of the fungal cell wall.

Sterols

Steroid alcohols in the cell membrane that provide relative rigidity and stability, especially in cells without a cell wall.

Nuclear Envelope

An external boundary of the nucleus composed of two parallel membranes perforated with small, regularly spaced pores.

Nucleolus

A site found in the nucleoplasm responsible for ribosomal RNA (rRNA) synthesis.

Chromatin

Genetic material of the cell made of linear DNA and histone proteins.

Rough Endoplasmic Reticulum (RER)

A series of membrane tunnels with attached ribosomes used for transporting materials from the nucleus to the cytoplasm and cell exterior.

Smooth Endoplasmic Reticulum (SER)

A closed tubular network without ribosomes that functions in nutrient processing and the synthesis and storage of nonprotein macromolecules like lipids.

Golgi Apparatus

An organelle consisting of flattened, disc-shaped sacs called cisternae; the site for protein modification and shipping.

Lysosomes

Vesicles containing enzymes involved in intracellular digestion of food and protection against invading microorganisms.

Cristae

Folds on the inner membrane of mitochondria that hold enzymes and electron carriers for aerobic respiration.

Mitochondrial DNA and Ribosomes

Unique mitochondrial features including circular strands of DNA and bacteria-sized $70S$ ribosomes.

Thylakoids

Structures within chloroplasts where the light-dependent reactions of photosynthesis occur.

$80S$ Ribosomes

The standard eukaryotic ribosome size, composed of $60S$ and $40S$ subunits.

Cytoskeleton

Intercellular framework composed of actin filaments, intermediate filaments, and microtubules.

Yeasts

Fungal cells with a round to oval shape that reproduce asexually by budding.

Hyphae

Long, threadlike cells found in the bodies of filamentous fungi.

Mycelium

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

Saprobe

An organism that obtains nutrients from the remnants of dead plants and animals in soil or aquatic habitats.

Sporangiospores

Asexual spores formed within a saclike head called a sporangium attached to a stalk (sporangiophore).

Ectoplasm

The clear outer layer of protozoan cytoplasm involved in locomotion, feeding, and protection.

Trophozoite

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

Cyst

The dormant, resistant stage of a protozoan life cycle that allows for survival in unfavorable conditions and helps in disease spread.

Conjugation

A form of sexual reproduction in ciliates where two cells fuse and exchange micronuclei.

Nematodes

Commonly known as roundworms, characterized by an elongated, cylindrical, unsegmented body.

Cestodes

A category of flatworms commonly referred to as tapeworms.

Trematodes

A category of flatworms commonly referred to as flukes.

Definitive (Final) Host

The host in which helminth adulthood and mating occur.

Intermediate Host

The host in which helminth larval development occurs.

Enterobius vermicularis

Also known as the pinworm or seatworm, a common helminth infestation of the large intestine.