Cell Structure

Cell Theory All living things are composed of cells Cells are the basic units of structure and function in living things All cells come from pre-existing cells

Prokaryotes vs. Eukaryotes Prokaryotes: do not have membrane bound organelles or a nucleus, all are unicellular Ex: bacteria Eukaryotes: have membrane bound organelles and a nucleus, may be either unicellular or multicellular

Cell Membrane Regulates what enters & leaves the cell. Protects & supports the cell. Located around the outside of the cell. Made of a phospholipid bilayer with proteins and carbs.

Cell Wall Protects and gives structure to the cell. Located outside the cell membrane. Found in bacteria, fungi, and plants.

Nucleus Information center of the cell. Contains DNA (chromatin), directs cellular activities.

Cytoplasm Encases, cushions and protects the internal organelles Located between the nucleus and cell membrane.

Mitochondria Makes energy for the cell.

Chloroplast Makes sugar from sunlight Found in plants, some protists, and some bacteria

Endoplasmic Reticulum Manufactures and transports materials. Smooth ER- walls are smooth, involved in lipid synthesis Rough ER – ribosomes are stuck to its walls. Involved in protein synthesis.

Ribosomes Makes proteins Composed of RNA and protein Some are attached to parts of the ER, some are free in the cytoplasm

Golgi Apparatus Collect, modify, package, and distribute molecules (such as lipids and proteins from ER).

Lysosomes Have enzymes that digest materials in the cell (food, foreign material, waste) Usually NOT found in plants.

Vesicle Membrane bound sac that transports materials in and out of the cell.

Vacuoles Store water, salts, proteins, and carbohydrates. Much larger in plants cells than animal cells.

Centrioles Involved in cell division.

Cytoskeleton Framework in the cell Made of microfilaments (movement) and microtubules (structural support)