Each organelle is a compact, highly organized system of molecules and macromolecules, usually bounded by a membrane, that has a definite size and generally recognizable shape under the electron microscope.

Protruding from the surface of many cells are motile projections that beat to move the surrounding liquid.

These projections are anchored in the cell membrane, the thin molecular covering of all cells.

Just beneath the surface of the membrane starts a network of filaments and fibers that interlace though out the cytoplasm.

A part of the cell involved in protein synthesis is the endoplasmic reticulum, a finely divided system of membrane-enclosed compartments.

Almost all eukaryotic cells, plant and animal, contain a golgi apparatus, a system of stacked cisternae in which proteins are processed.

Energy transformations take place in the mitochondria, where food is broken down and the energy transferred to ATP molecules.

The genetic material found in the nucleus is organized into chromosomes.