Cells

ucleus	The cell structure that directs all of the activities of the cell
ucleolus	The site of ribosome production inside the nucleus; called "little nucleus"
ell Membrane	The thin, flexible envelope that surrounds a cell and allows passage in and out of the cell
ytoplasm	The region between the cell membrane and the nucleus
acuole	A large, round sac in the cytoplasm of a cell that stores water, food, enzymes, and other materials
hloroplast	A cell organelle containing chlorophyll that is involved in the process of photosynthesis
itochondrion	The powerhouse of the cell in which cellular respiration occurs
ell Wall	The outermost boundary of plant cells that is made of cellulose
uclear Membrane	A membrane that surrounds the nucleus and allows passage in and out of the nucleus
ibosome	The protein-making site of the cell
ndoplasmic Reticulum	Tubular passageways in the cells through which materials are transported
ysosome	A small, round structure in a cell involved in the digestive activities of a cell

All cells have a nucleus. The nucleus directs all of the activities of the cell and contains the nucleolus, the protein-making site of the cell. They also have a cytoplasm, which is the jelly-like substance between the cell membrane. The cell membrane is the flexible envelope surrounding the cell. The nuclear membrane is the envelope surrounding the nucleus. Both types of cells contain an endoplasmic reticulum, which is the tubular passageway through which materials are transported. All cells contain a mitochondrion, which is the powerhouse of the cell. It also provides most of the energy for the cell. All cells also contain ribosomes, which are the protein-making sites of the cells.

Plant cells have a chloroplast, which contains chlorophyll that is used in photosynthesis. They also have a cell wall, which is made up of cellulose, a nonliving material. The cell wall provides support and protection for the plant cell, allowing the plant to grow tall and become strong. Neither the cell wall or the chloroplast is found in an animal cell. Vacuoles are in most plant cells and some animal cells. Vacuoles can store materials such as food and water, as well as waste in the cell. The plumpness of the vacuole depends on how much water is in it. It is this plumpness that makes a plant firm. Lysosomes are commonly found in animal cells, but are rare in plant cells. They are involved in the digestive activities of the cell.