Lipids and Cell Membrane Structure Lipids a k

Lipids and Cell Membrane Structure

Lipids (a. k. a. Fats) • Lipids are NOT soluble in water. – Lipids are non-polar. • Lipids store large amounts of energy. • The monomers are called fatty acids. • Lipids make up most of the cell membrane.

Phospholipids §The cell membrane is made of special lipids called phospholipids. §Polar heads are hydrophilic – “water loving” §Non-polar tails are hydrophobic – “water fearing” §The polarity determines the arrangement of the phospholipids. §Phospholipids form two layers – called lipid bilayer §Polar heads face outward (water outside and inside the cell) §Non-polar tails face inward (creates barrier to protect the cell)

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

Cell Membrane Proteins 1. Integral Proteins § Proteins that penetrate completely through the membrane (inside) 2. Peripheral Proteins § § Embedded but not all the way Located on the outside surface and function to help transport different substances into and out of the cell. fluid mosaic model

Cell Membrane Functions • Controls what enters and exits the cell. – Selectively Permeable - only lets certain molecules into and out of the cell • Maintains cell’s shape. • Connects each cell to other cells near it. • Can allow movement of the cell – parts can move around each other, called the fluid mosaic model