Cell Biology Vocabulary

Vocabulary flashcards covering key cellular structures, organelles, and biological terms from the lecture notes.

Cell wall

A protective layer external to the plasma membrane in the cells of plants, prokaryotes, fungi, and some protists. Polysaccharides such as cellulose (in plants and some protists), chitin (in fungi), and peptidoglycan (in bacteria) are important structural components of cell walls.

Chloroplast

An organelle found in plants and photosynthetic protists that absorbs sunlight and uses it to drive the synthesis of organic compounds from carbon dioxide and water.

Cytoplasm/cytosol

Cytoplasm: The contents of the cell enclosed by the plasma membrane; in eukaryotes, the portion exclusive of the nucleus. Cytosol: The semifluid portion of the cytoplasm.

Endomembrane system

The collection of membranes inside and surrounding a eukaryotic cell, related either through direct physical contact or by the transfer of membranous vesicles; includes the plasma membrane, the nuclear envelope, the smooth and rough endoplasmic reticulum, the Golgi apparatus, lysosomes, vesicles, and vacuoles.

Endoplasmic reticulum

An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Lysosome

A membrane-enclosed sac of hydrolytic enzymes found in the cytoplasm of animal cells and some protists.

Endosymbiosis

A mutually beneficial relationship between two species in which one organism lives inside the cell or cells of another organism.

Eukaryotic cell

A type of cell with a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with eukaryotic cells (protists, plants, fungi, and animals) are called eukaryotes.

Glycolipid

A lipid with one or more covalently attached carbohydrates.

Glycoprotein

A protein with one or more covalently attached carbohydrates.

Golgi apparatus

An organelle in eukaryotic cells consisting of stacks of flat membranous sacs that modify, store, and route products of the endoplasmic reticulum and synthesize some products, notably noncellulose carbohydrates.

Mitochondrion (plural, mitochondria)

An organelle in eukaryotic cells that serves as the site of cellular respiration; uses oxygen to break down organic molecules and synthesize ATP.

Nuclear envelope

In a eukaryotic cell, the double membrane that surrounds the nucleus, perforated with pores that regulate traffic with the cytoplasm. The outer membrane is continuous with the endoplasmic reticulum.

Plasma membrane

The membrane at the boundary of every cell that acts as a selective barrier, regulating the cell's chemical composition.

Endosymbiont theory

The theory that mitochondria and plastids, including chloroplasts, originated as prokaryotic cells engulfed by host cells. The engulfed cell and its host cell then evolved into a single organism.

Ribosome

A complex of rRNA and protein molecules that functions as a site of protein synthesis in the cytoplasm; consists of a large subunit and a small subunit. In eukaryotic cells, each subunit is assembled in the nucleolus.

Prokaryotic cell

A type of cell lacking a membrane-enclosed nucleus and membrane-enclosed organelles. Organisms with prokaryotic cells (bacteria and archaea) are called prokaryotes.

Rough ER

That portion of the endoplasmic reticulum with ribosomes attached.

Smooth ER

That portion of the endoplasmic reticulum that is free of ribosomes.

Transport Vesicle

A small membranous sac in a eukaryotic cell's cytoplasm carrying molecules produced by the cell.

Vacuoles

A membrane-bounded vesicle whose specialized function varies in different kinds of cells.