Lipids and Cell Membrane Structure

1. Lipids and Cell Membrane Structure

2. Lipids make up MOST of the cell membrane • Lipids are not soluble in water • Lipids store large amounts of energy • The monomers (smallest part of a lipid) are called fatty acids • Fatty acids can combine to make complex lipids by a reaction called dehydration synthesis (aka condensation)

3. Fatty Acids – unbranched carbon chain that makes up most lipids 2 parts: 1. Carboxyl Head • -COOH • Polar – attracted to water • Hydrophilic – “water loving” 2. Hydrocarbon Tail • H-C chain • Nonpolar – stays away from water • Hydrophobic – “water fearing”

4. Types of Fatty Acids • Saturated • Each C always bonded to 4 other atoms • Molecule contains the max. # of H atoms • Unsaturated • Double/triple bonds between some C atoms • Less H atoms needed

5. Phospholipids are lipids with 2 fatty acids attached to one glycerol. They have a polar and a non-polar end that align in the cell membrane forming a bi-layer

6. Cell Membrane Structure • The cell membrane contains fats, proteins, and carbohydrates.

7. 2 Kinds of cell membrane proteins • Integral Proteins • Proteins that penetrate completely through the lipid bilayer (inside) • Function to help transport different substances into and out of the cell. 2. Peripheral Proteins • Embedded into the bilayer • Located on the outside surface fluid mosaic model

8. Cell Membrane Functions • It controls what enters and exits the cell. It is considered selectively permeable since it only lets certain molecules into and out of the cell • It maintains the cell shape • It connects each cell to other cells near it • It can allow movement of the cell because the parts can move around each other, called the fluid mosaic model fluid mosaic model