3. Transport across Cell membrane

• What is the structure of phospholipids?

  One fatty acid replaced by phosphate group
• What is the behavior of phospholipids in water?

  Form a bilayer with hydrophilic heads
• What are three differences between animal and plant cells?

  Plant cells have chloroplasts, vacuoles, and walls
• What effect does thick mucus have in the gaseous exchange system?

  It blocks airways and reduces oxygen flow
• Where does the genetic material of a prokaryotic cell exist?

  In the cytoplasm
• Why are cell membranes important?

  • Control entry and exit of substances
  • Maintain homeostasis
  • Facilitate communication between cells
• What is the structure of the cell membrane?

  It consists of a phospholipid bilayer
• What causes cystic fibrosis (CF) in relation to cell membranes?

  A faulty chloride channel protein in epithelial cells
• What is the basic structure of a phospholipid bilayer?

  Two layers of phospholipids
• How do phospholipids differ from triglycerides?

  Phospholipids have two fatty acid chains
• What is the property of the phosphate head of phospholipids?

  It is polar and hydrophilic
• What is the property of the tails of phospholipids?

  They are non-polar and hydrophobic
• What happens when phospholipids are added to water?

  They arrange to avoid water contact
• How is the phospholipid bilayer formed?

  • Bulky fatty acid tails favor bilayer formation
  • Critical for biological functions
  • Forms compartments around and within cells
• Why is the phospholipid bilayer the most stable arrangement?

  Hydrophobic tails avoid water contact
• What components are included in the phospholipid bilayer structure?

  • Bilayer of phospholipids
  • Intrinsic proteins
  • Extrinsic proteins
  • Cholesterol
  • Glycolipids
  • Glycoproteins
• What are the cells called that line the trachea?

  Ciliated epithelial cells
• what cell makes mucus ?

  goblet cells
• What is mucus made up of?

  Mucin(gives it its sticky property), water, salt, sodium and chloride ions, proteins
• What’s Ficks law?


  Rate of diffusion∝surface area∝concentration gradient/diffusion distance