1. The Cell (Plasma) Membrane

2. Cell membrane (semi-permeable) – controls what goes in/out of the cell to maintain homeostasis (equilibrium)
Made up of a phospholipid bilayer with channel proteins (transport proteins)

3. Phospholipids Fatty acid tails – hydrophobic = nonpolar
Phosphate head – hydrophilic = polar
attracted to water
repelled by water
inside cell = cytoplasm
outside cell = extracellular fluid

4. Phospholipid bilayer polar hydrophilic heads nonpolar hydrophobic
tails
polar
hydrophilic
heads

5. Transport Proteins
Act as doors through the cell membrane to allow specific molecules in and out
2 Types
Peripheral Proteins – on the surface of the membrane
Integral Proteins (Transmembrane Proteins) – in the phospholipid bilayer

8. Extracellular Fluid Cytoplasm Phospholipids Cholesterol
Integral Proteins
Peripheral
Protein
Cytoplasm

9. Functions of the Cell Membrane
The Plasma Membrane
4/14/2018
Protective barrier – isolates the cytoplasm (intracellular fluid) from the external environment (extracellular fluid)
Regulates the exchange of substances (selectively permeable) to maintain homeostasis
Cell recognition
Communication with other cells
G. Podgorski, Biol. 1010