Anatomy & Physiology Chapter 3

A cell from which other types of more specialized cells originate (or stem).

Theory consisting of three basic principles: (1) All living things are composed of cells and cell products. (2) A single cell is the smallest unit that exhibits all the characteristics of life. (3) All cells come only from preexisting cells.

Membrane surrounding the cell, consisting of a phospholipid bilayer with embedded cholesterol and proteins.

An organism composed of cells with nuclei and internal membrane-bound organelles.

One of many small cellular structures that perform specific functions for the cell as a whole.

A single-celled organism that lacks the nucleus and the membrane-bound organelles characteristic of eukaryotes.

Membrane transport processes that do not require cellular energy.

The movement of molecules from one region to another as the result of random motion; moves from higher concentration to lower concentration

The quality of allowing certain substances to pass while restricting the movement of others.

The net diffusion of water across a selectively permeable membrane, such as a cell membrane.

Passive transport of a substance into or out of a cell along a concentration gradient; requires a carrier protein.

A protein molecule of the cell membrane whose function is to transport one or more molecules across the cell membrane.

Process that transfers a substance into or out of a cell, usually against its concentration gradient.

An active transport protein of the plasma membrane that simultaneously transports three sodium ions (Na+) out of the cell and two potassium (K+) in.

Process by which fluids, extracellular particles, or even whole bacteria are taken into cells.