CELL STRUCTURE AND FUNCTION

3.2 Looking Inside Cells

Cell Wall•Rigid layer of nonliving material•Surrounds the cells of plants and some other organisms•Protects and supports•Made of cellulose•Strong, but permeable

Cell Membrane•Barrier separating the cell from its environment•Controls what substances enter and exit a cell•Semi-permeable

Nucleus•Control center of the cell•Contains the DNA

Cytoplasm•Clear, thick, gel-like fluid•Contains many organelles

Mitochondria•Small, rod-shaped organelles •"Powerhouses" of the cell•Convert food energy into energy the cell can use

Endoplasmic Reticulum•Maze of passageways•Helps form proteins •Carries material throughout the cell

Ribosome•Small, grain-like body•Some are attached to endoplasmic reticulum•Some float freely in the cytoplasm•Protein "factories"

Golgi Body• Flattened sacs and tubes• Receive proteins to be packaged and distributed to

other parts of the cell or even outside the cell

Chloroplasts•Large, green structures•Generally found only in plants•Capture energy from sunlight and convert it into sugar

Vacuole•Large water-filled sac•Storage areas•Plant cells usually have one large, central vacuole

Lysosome•Small, round structures•Contain chemicals for breaking down certain materials•Clean-up crew