Key terms of Concept 6l1

Organelle: Part of a cell with a specific function.

Plasma membrane: Thin outer boundary of a cell that regulates the traffic of chemicals between the cell and its surroundings.

Nucleus: In an atom, the central core that contains protons and neutrons in a cell, the part that houses the cell’s genetic material in the form of DNA.

Cytoplasm: Region of a cell between the nucleus and the plasma membrane.

Cell wall: Strong wall outside a plant cell’s plasma membrane that protects the cell and maintains its shape.

Prokaryotic cell: Cells lacking a nucleus and most other organelles.

Eukaryotic cell: Cells with a nucleus and other internal organelles.

Diffusion: Net movement of the particles of a substance from where they are more concentrated to where they are less concentrated.

Equilibrium: Point at which the number of diffusing molecules moving in one direction is equal to the number moving in the opposite direction.

Selectively permeable membrane: Membranes that allows some substance to pass more easily than others and blocks the passage of some substance altogether.