1. Cell Membrane

2. Function/Purpose: Homeostasis
1) Controls what goes in/out of the cell (is semipermeable or selectively permeable) 2) Also acts a barrier to keep the internal metabolism/reactions separate from the outside

3. Structure Cell membrane is made of phospholipids
Has 2 layers so it is referred to as a phospholipid bilayer

4. Structure
Phospholipids have a polar/hydrophilic head and nonpolar/ hydrophobic tail. This causes the double membrane to have a hydrophobic environment on the inside and hydrophilic surfaces on both sides outside

5. Structure
Proteins are scattered throughout the cell membrane, there are 2 types:
Peripheral: proteins that only attach to one side of the membrane and do not go all the way across
Integral: proteins that span from one side of the membrane to the other

6. Fluid Mosaic Model
The Fluid Mosaic Model states that the cell membrane is like an ocean of phospholipids and proteins, they are able to move around freely

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

9. copyright cmassengale
The Plasma Membrane
11/9/2018
Cell Membrane
The cell membrane is flexible and allows a unicellular organism to move
copyright cmassengale
G. Podgorski, Biol. 1010

10. Functions of the Cell Membrane
The Plasma Membrane
11/9/2018
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

11. Cell Membrane parts A-phospholipid bilayer B-integral protein
C-Glycoprotein
E-glycolipid
F-fatty acid tails
G-phosphate head
H-peripheral protein
I-cholesterol

13. Functions of cell membrane parts
A-phospholipid bilayer-homeostasis
B-integral protein-transport across membrane, spans entire cell membrane
C-Glycoprotein-cell communication/recognition
E-glycolipid-cell communication/recognition
F-fatty acid tails-bilayer,repel water, hydrophobic
G-phosphate head- bilayer, attract water,hydrophillic
H-peripheral protein-does not span the membrane
I-cholesterol –flexibility of membrane