1.3 Membrane Structure

Question 1

Fluid Mosaic Model proposed by Singer & Nicholson using techniques such as freeze-etching. It is amphipathic (part hydrophobic & hydrophilic)

Answer 1

• Proteins are distributed throughout the bilayer in a mosaic pattern
• Phospholipid bilayer
• Hydrophilic phosphate head (Outside)
• Hydrophobic hydrocarbon tails (Inside)

Question 2

Glycoproteins

Answer 2

• Cell recognition site

- Cell adhesion

Question 3

Phospholipid Bilayer

Answer 3

• Barrier to water soluble compounds
• Passage of lipid soluble substances
• Fatty acids maintain fluidity

Question 4

Cholesterol

Answer 4

• Regulates fluidity/stability
• Storage
• Restricts movement of phospholipids
• Influences permeability of membrane

Question 5

Integral Proteins

Answer 5

• Permits movement of ions

- Provide hydrophobic channels for charged ionic or polar molecules through facilitated diffusion/active transport