Three major parts of the cell
1. Plasma Membrane
2. Cytoplasm
3. Nucleus
Plasma Membrane - Functions
*Forms outer cell boundary
*Separates internal environment of the cell from the external environment
*Regulates what gets in and out of the cell
Plasma Membrane - Structure
*Lipids
*Proteins
*Carbohydrates
Lipids of the Plasma Membrane
*Phospholipids (phospholipid bylayer) are the predominant lipid
*Cholesterol is found between phospholipids to provide stability
Functions of Proteins in the Plasma Membrane
*Makers
*Attachment sites
*Channels
*Receptors
*Enzymes
*Carriers
Marker Molecules
*Protein of the plasma membrane
*Involved in cell to cell recognition
*Most are glycoproteins, but some are glycolipids
*It is the "glyco" part that is responsible for recognition
Attachment Proteins
*Proteins of the plasma membrane
*Attach cells to other cells, extracellular molecules or intracellular molecules
Channel Proteins
*Proteins of the plasma membrane
*Allows ions of the correct size, shape and charge to pass through the channel, moving into or out of the cell
*Nongated ion channels, gated ion channels and ligand gated ion channels are all types of channel proteins
Receptor Proteins
*Proteins of the plasma membrane
*Proteins with an exposed receptor site on the outer cell surface, which can attach to specific chemical signals (ligands)
Enzymes
*Proteins of the plasma membrane
*Catalyze (speeds up) chemical reactions on either the inner or outer surface of the plasma membrane
Carrier Proteins
*Proteins of the plasma membrane
*Move substances (ions or molecules) from one side of the plasma membrane to the other
Carbohydrates of the Plasma Membrane
*Found on the outer surface of the plasma membrane (form the glycocalyx)
Cytoplasm
*Everything on the inside of the plasma membrane except the nucleus
*Site where most cellular activity takes place
*Contains four major parts:
-Cytosol
-Cytoskeleton
-Inclusions
-Organelles
Cytosol
*Fluid portion of cytoplasm
Cystoskeleton
*Provides support and structure
*Involved with the movement of cellular structuresn("highway system inside the cell")
Inclusions
*Miscellaneous substances in the cytoplasm not cytosol, cytoskeleton or organelles
*Examples: lipid droplets, hemoglobin, melanin
Organelles
*Machinery of the cell
*Each carries out a specific function