Membranes (phospholipid bilayer)

Membranes: - Phospholipid Bilayer

Key Words:

• Cell membrane
• Fluid-mosaic model
• Hydrophobic
• Hydrophilic
• Phospholipids

Membranes need to be flexible and be able to break/fuse easily.

Membranes allow cellular compartments to have different conditions and act as a barrier within a cell.

Major roles of membranes:

• Cell recognition and signalling
• Partially permeable membrane to let substances in and out of the cell
• Keeps everything in the cell together
• Holding the components of metabolic pathways seperate
• Seperating cell components from cytoplasm

Membrane Structure:

• All have a similar structure
• Usually between 7nm and 10nm
• Invisible to light microscopes but visible to electron microscopes
• Many different types of proteins found within double layer
• Formed by a double layer of phospholipids

Phospholipids are made up of a hydrophilic head which loves water and is made of a phosphate group. They also have the hydrophobic end which are fatty acid tails that must stay away from water.

Question:

Explain why…