Introduction to Protists and Domains of Life

Vocabulary flashcards focusing on cellular structures, domain taxonomy, protist classification, and general biological principles based on the lecture notes.

Eukaryote

An organism whose name means 'true nucleus,' characterized by having its DNA enclosed within a protective nuclear envelope, and which is not an animal, plant, or fungus.

Prokaryote

An organism whose name means 'before the nucleus,' which lacks a nuclear envelope, leaving its DNA more exposed to the environment.

Protist

Any eukaryotic organism that is not an animal, a plant, or a fungus.

Structural pigments

Coloration formed by molecules packed closely together causing light to refract and diffract through layers, rather than using a standard pigment molecule.

Melanin

The brown protein pigment found in skin.

Diatom

A type of protist whose name translates to 'two parts' or 'two pieces,' referring to the two hard protective outer structures it constructs.

Amoeboid movement

A method of cellular movement where the cytoskeleton pushes outward, deforming the plasma membrane so that the cytoplasm follows.

Cilia

Filamentous protein structures (meaning 'eyelashes') extending outside the cell membrane that belong to the cytoskeleton and are used for locomotion.

Unicellular

Describing an organism that consists entirely of a single cell.

Multicellular

Describing an organism composed of many cells.

Photosynthesis

The chemical process in which light photons ('photo') are used to synthesize ('putting together') glucose.

Archaea

A domain of life whose name means 'old stuff,' believed to represent the earliest life forms on Earth prior to bacteria.

Endosymbiosis

The evolutionary process ('process of living together inside') in which one living organism began residing inside another, giving rise to eukaryotic protists from prokaryotic ancestors.

Excavata

A eukaryotic supergroup named for the visually scooped-out or excavated appearance of its cells.

Archaeplastida

A eukaryotic supergroup named for 'old plastids,' referencing the early evolutionary acquisition of cellular organelles such as chloroplasts.

Uniconta

A eukaryotic supergroup named for having a single ('uni') flagellum ('canta').

Opisthokonta

A subgroup within Uniconta where the flagellum is located 'in the back' ('opista'), driving the cell forward.

Biological evolution

Changes in an organism's DNA over time, originating from mutations or replication errors.

Homeostasis

The state of internal stability maintained within living systems through regulatory feedback mechanisms.

Negative feedback

The dominant type of biological feedback that stabilizes systems and maintains homeostasis.

Positive feedback

A rare type of biological feedback that functions as an amplifier rather than maintaining stability.