Biology Vocab

Vacuole: An organelle that stores key molecules; very prominent in most plant cells.

Chloroplast: An organelle that contains the molecular machinery required for photosynthesis.

Cell wall: A stiff structure outside of many types of cells, usually made primarily of carbohydrates.

Endoplasmic reticulum (ER): A eukaryotic organelle that forms a branching network of narrow tubes and flattened sacs. The place where proteins, membrane lipids, and other molecules are synthesized and/or processed. Can have ribosomes associated with it (rough ER) or not (smooth ER).

Golgi: An organelle comprised of stacked, flattened sacs, where proteins and other molecules are processed and packaged for shipment to specific destinations.

Actin filaments: Small-diameter cytoskeletal fibers made of subunits of the protein actin.

Intermediate filaments: Cytoskeletal fibers whose size is intermediate between those of actin filaments and microtubules and can be made from a variety of protein subunits.

Microtubules: Large-diameter, hollow cytoskeletal elements made of pairs of the proteins α-tubulin and β-tubulin.

Cytoskeleton: Rod-like proteins inside cells that function in structural support, transport of materials, and movement in some species.

Cell wall: A stiff structure outside the cell membrane composed of carbohydrates and other molecules.

Flagellum: A long, flexible structure that extends from the cell and whips or rotates to propel the cell through water.

Nucleus: An organelle unique to eukaryotes enclosed by a double membrane and containing the cell’s chromosomes.

Mitochondrion: An organelle found in all eukaryotes that functions in “burning” sugars to provide energy for the cell.

Eukaryote: A lineage of species with cells that contain a nucleus and mitochondria.

Prokaryote: A species in the lineages Archaea and Bacteria, with cells that lack a nucleus.

Ribosome: A molecular machine consisting of RNA and proteins that is the site of protein synthesis

Organelle: Any membrane-bound compartment inside a cell.

Chromosome: A DNA molecule — circular or linear, depending on the species — usually associated with specific proteins that bind to the DNA.