Cell parts

Differing in size, shape, and function, the cell is the smallest functional unit of tissues and organs.    Each cell is somewhat self-contained and self-maintaining:

•  It can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce
• Human cells have a surrounding protective membrane.   Enclosing a salty, watery cytoplasm in which is floating a set of membrane-bound organelles ("little organs"), which perform a number of vital functions for the cell.

For example:

•  The cell nucleus.   Houses DNA - the cell's genetic blueprint containing the building instructions for various protein molecules, such as enzymes;
•  The mitochondrion.   The cell's "Power Plant"
•  The endoplasmic reticulum.   The transport network for active molecules;
•  Ribosome.    Primary site of protein synthesis
•  The Golgi complex/apparatus.    The cell's central delivery system and a site for protein processing, packaging, and transport.
•  Lysosome.    Contains enzymes that break down waste materials and cellular debris

 Centriole.    Two per cell; help with mitosis and meisosis when cell divides.