The Cell
Cell Theory
1. All living things are made up of cells
2. Cells are the basic units of structure and function of all living things
3. All cells come from preexisting cells
Classes of Cells
1. Prokaryotic (no nucleus)
2. Eukaryotic (true nucleus)
Overview of the Cell
1. Cell parts are called organelles (mini-organs)
2. General Functions
Manufacture and Breakdown
The Nucleus
1. Nucleus- Control Center
2. Nucleolus- makes ribosomes
Endoplasmic Reticulum
1. Endoplasmic reticulum- a network of passageways
2. Ribosomes assemble proteins
Golgi Body
1. Golgi body packages products in membrane-bound vesicles
Vacuoles and Lysosomes
1. Vacuole- large membrane-bound sacs that store:
2. Lysosome- a vacuole that contains digestive enzymes
Energy, support, and movement
Chloroplasts
1. Chloroplasts convert energy from the sun into sugars
Mitochondria
1. The mitochondria release energy from sugar
Cytoskeleton
1. The cytoskeleton is a network of fibers extending throughout the cytoplasm
2. Centrosome- (microtubules)
Cilia and Flagella
1. Some cells have projections that enable the cell to move
Cell Wall
1. Found in Plant cells, but not animal
2. Contains pore to allow materials to pass through
3. Adjacent primary cell walls glued together by “middle lamella”
4. (Different cell walls found in bacteria, archaea, fungi, & some algae)
Membranes: structure/function
Membrane Structure
1. The cell membrane separates the interior of a cell from its surroundings
2. Each membrane is composed of proteins & phospholipids (animals contain cholesterol)
3. Membranes are selectively permeable (control what passes across)
4. Other functions include:
Types of Transport
1. Passive transport- diffusion across a membrane
2. Active transport- the use of energy to move molecules
3. Bulk transport- the use of membrane vesicles to move large particles across the membrane
Diffusion and Osmosis
Diffusion
1. Particles move from areas of high concentration to areas of low concentration by diffusion
2. Equilibrium is reached when particles are evenly spread out
Osmosis
1. The diffusion of water is called osmosis
2. Osmosis affects the water balance of cells
Membranes: structure/function
Diffusion and osmosis
Manufacture and Breakdown
Energy, support, and movement