Protozoans, Porifera, and Cnidaria Lecture Review

Vocabulary flashcards covering protozoan biology, Amoeba, Paramecium, Phylum Porifera, and Phylum Cnidaria based on lecture notes.

Protozoa

A term coined by Goldfuss (1817) referring to primitive, acellular or microscopic eukaryotic animals belonging to Kingdom Protista and Phylum Protozoa.

Encystment

A common protective stage in protozoans that helps them survive unfavourable environmental conditions, such as a lack of food.

Nummulite

A fossil protozoan that measured up to $19\,cm$ in size.

Ectoplasm

The outer, thin, and transparent layer of cytoplasm in protozoans.

Endoplasm

The inner, granular layer of cytoplasm in protozoans that contains cellular organelles.

Macronucleus

The large, kidney-shaped vegetative nucleus in dimorphic protozoans that controls vegetative and metabolic activities.

Micronucleus

The small, spherical diploid nucleus in dimorphic protozoans that functions specifically in reproduction and heredity.

Lobopodia

A specific type of pseudopodia found in Amoeba used for locomotion.

Trichonympha

A protozoan that maintains a mutualistic symbiotic relationship inside the hindgut of lower termites and wood-feeding cockroaches, producing enzymes that break down cellulose into simple sugars.

Uroid

A wrinkled structure located at the posterior part of the body in Amoeba.

Cyclosis

The continuous streaming movement of cytoplasm within a cell that aids in locomotion, shape determination, and nutrient cycling.

Methyl green acetic acid

A chemical reagent used to visualize the nucleus of Amoeba.

Circumvallation

An ingestion method in Amoeba where pseudopodia extend around highly mobile prey to form a cup-like food cup.

Circumfluence

An ingestion method in Amoeba where pseudopodia directly touch less active or immobile bacteria to initiate food vacuole formation.

Pinocytosis

The bulk ingestion of liquid food through the plasmalemma, forming pinocytosis channels and pinosomes.

Holotrichous Condition

The structural condition in Paramecium where the entire body surface is uniformly covered with cilia.

Caudal tuft

A group of elongated cilia located at the posterior end of Paramecium.

Kinetosome

Also known as a basal body; a minute structure at the base of a cilium or flagellum featuring a $(9+0)$ microtubule triplet arrangement.

Axoneme

The microtubule-based cytoskeletal core of a cilium or flagellum, featuring a $(9+2)$ microtubule arrangement in motile cilia.

Cytoproct

Also known as the anal pore; the specific body location in Paramecium where waste-laden food vacuoles move to expel undigested content.

Trichocysts

Organelles situated right under the cell membrane in the ectoplasm of Paramecium, serving functions of defense against predators and anchorage.

Porifera

A phylum of multicellular, predominantly marine, sedentary organisms commonly known as sponges, meaning 'pore bearers'.

Ostia

Numerous minute body pores on sponges that serve as entry channels for water currents entering the body.

Spongocoel

Also known as the paragastric cavity; the single, central, and spacious cavity inside a sponge.

Osculum

The large main opening on a sponge through which water exits the body.

Pinacoderm

The outermost body layer of a sponge composed of flattened epithelial-like cells called pinacocytes.

Choanocytes

Specialized flagellated collar cells lining the inner layer or radial canals of sponges that generate water currents to filter food particles and oxygen.

Archaeocytes

Also known as amoebocytes; mobile, multipurpose cells present in the mesohyl of sponges that aid in digestion and nutrient transportation.

Sclerocytes

Specialized cells in sponges that secrete skeletal elements known as spicules.

Gemmules

Internal asexual reproductive structures formed by certain freshwater sponges like Spongilla to survive harsh environmental conditions.

Calcarea

A class of Phylum Porifera characterized by shallow marine habitats and skeletons composed of $CaCO_3$ spicules with 3 or 4 rays.

Hexactinellida

A class of Phylum Porifera, commonly called glass sponges, characterized by 6-rayed siliceous spicules forming an intricate lattice-like structure.

Demospongia

The largest class of sponges, comprising over 90% of species, featuring predominantly leuconoid structures and skeletons made of spongin fibers, siliceous spicules, or both.

Megascleres

Large spicules in sponges that form the primary supporting structural framework.

Microscleres

Small spicules scattered within the mesenchyme of sponges.

Cnidaria

Also known as Coelenterata; a phylum of diploblastic, tissue-grade aquatic animals characterized by specialized stinging cells called cnidoblasts.

Nematocyst

A microscopic stinging organelle found inside a cnidocyte, containing a tiny bulb-shaped capsule, coiled hollow thread, and venom.

Gastrozooids

Specialized feeding zooids in a polymorphic coelenterate colony responsible for food collection.

Dactylozooids

Specialized protective zooids in a coelenterate colony that serve defense functions.

Gonozooids

Budding individuals in a coelenterate colony that produce new individuals asexually.

Polyp

A sessile, cylindrical, asexual body form of a coelenterate with an upward-facing mouth.

Medusa

A free-swimming, sexual body form of a coelenterate with a downward-facing mouth.

Metagenesis

The alternation of generations in coelenterates between an asexual polyp phase and a sexual medusa phase.