1. Cell Membrane Structure

2. The Cell Membrane
It is important to know the composition of the cell membrane because each part is responsible for bringing a type of nutrient into the cell.

3. Components of the cell membrane
Phospholipids (Yes these are a type of lipid)
Proteins
Carbohydrates

4. Phospholipids Make up a majority of the cell membrane
Small molecules (such as water and oxygen) can pass freely between phospholipids
Phospholipid structure:
Hydrophilic head (loves water)
 Faces towards water
Hydrophobic tail (Water fearing)
 Faces away from water

5. Phospholipids Exist in a bilayer – “2 layers”
Heads face out of the cell and inside the cell
Tails cluster in the middle (see pictures)

6. Proteins
Some are embedded on the inside of the cell membrane – Intrinsic proteins
Some are embedded on the outside of the cell membrane – Extrinsic proteins
Some pass through the cell membrane – Transmembrane Proteins
All are involved in moving things into or out of the cell membrane

7. Proteins in the Cell Membrane
Transmembrane Protein
 Goes through the cell membrane
Extrinsic Protein
Found on outside of cell membrane
Intrinsic Protein – Found on inside of cell membrane

8. Carbohydrates Made of Glycogen (Type of polysaccharide) 2 types:
Glycoproteins
Attached to proteins on the cell membrane
Used in cell to cell recognition
Glycolipids
Attached to phospholipids on the cell membrane
Used to recognize foreign substances in the environment
Both are found on outside of cell membrane

9. Carbohydrates
Phospholipids
Protein

10. Cell Membrane Structure Review
Made mainly of Phospholipids
Exist in a bilayer
Hydrophilic head faces outside and inside of cell
Hydrophobic tail faces the middle of the membrane
Proteins are embedded on the surface and through the membrane
Intrinsic – Inside of cell
Extrinsic – Outside of cell
Transmembrane – Extend through cell

11. Cell Membrane Structure Review
Carbohydrates extend from the surface of the membrane to sense the environment
Glycolipids – Attach to phospholipids
Glycoproteins – Attach to proteins