Chapter 3 anatomy

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 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

*Attachment sites

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)


*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)


*Everything on the inside of the plasma membrane except the nucleus
*Site where most cellular activity takes place
*Contains four major parts:


*Fluid portion of cytoplasm


*Provides support and structure
*Involved with the movement of cellular structuresn("highway system inside the cell")


*Miscellaneous substances in the cytoplasm not cytosol, cytoskeleton or organelles
*Examples: lipid droplets, hemoglobin, melanin


*Machinery of the cell
*Each carries out a specific function