Lecture 01, 2

• What is the structure of the plasma membrane?

  Bilayer of phospholipids with proteins

  
• What is the role of membrane transport?

  Facilitates movement of substances across membranes
• What are the types of membrane transport?

  • Simple diffusion
  • Facilitated diffusion
  • Primary active transport
  • Secondary active transport
  • Endocytosis
  • Exocytosis
  • Water transport and osmosis
• What is simple diffusion?

  Movement of molecules from high to low concentration
• What is facilitated diffusion?

  Transport of molecules via channels or carriers

  
• What is primary active transport?

  Transport using ATP directly against a gradient
• What is secondary active transport?

  Transport using energy from another molecule's diffusion
• What is endocytosis?

  Process of taking substances into the cell

  
• What is exocytosis?

  Process of releasing substances from the cell
• What is osmosis?

  Net diffusion of water across a membrane
• What is the importance of the plasma membrane?

  Acts as a cell border and drug target
• What is the fluid mosaic model?

  Describes the structure of the plasma membrane
• What are the components of the plasma membrane?

  Phospholipid bilayer, proteins, carbohydrates

  
• What is the role of membrane proteins?

  Facilitate transport and communication across membranes
• What are glycolipids and glycoproteins?

  Carbohydrates attached to lipids and proteins
• Why is membrane transport important?

  Regulates cell volume and metabolic processes
• What is passive transport?

  Transport that does not require energy
• What is the driving force for simple diffusion?

  Electrochemical gradient
• How does membrane permeability affect transport rate?

  Higher permeability increases transport rate
• Which substances are permeable through the membrane?

  Steroids, gases, water, urea, glycerol
• Which substances are non-permeable through the membrane?

  Sugars, amino acids, nucleosides, ions
• What factors affect membrane permeability?

  Lipid solubility, size, temperature, thickness
• What is carrier-facilitated diffusion?

  Transport using specific carriers down a gradient
• What determines the rate of facilitated diffusion?

  Rate of carriers, concentration gradient, number of carriers
• What is the function of ion channels?

  Allow specific ions to pass through the membrane
• What is the role of Na+/K+-ATPase?

  Maintains Na+ and K+ concentration gradients
• What is the function of secondary active transport?

  Uses ion diffusion energy to transport substances
• What is phagocytosis?

  Process of engulfing large particles into the cell

  
• What is pinocytosis?

  Process of taking in small particles and fluids
• What is receptor-mediated endocytosis?

  Specific uptake of macromolecules via receptors

  
• What is the role of aquaporins?

  Facilitate water transport across membranes
• How does osmosis occur?

  Water moves down its concentration gradient
• What is the effect of tonicity on cells?

  Affects cell volume and osmotic balance
• What are the types of tonicity?

  • Isotonic: no change in cell volume
  • Hypotonic: cell swells
  • Hypertonic: cell shrinks
• What is the summary of membrane transport types?

  Includes diffusion, active transport, endocytosis, and osmosis

  
• What is the role of water transport in renal function?

  Concentrates urine through osmosis
• What is the role of membrane transport in metabolic processes?

  Regulates substrate concentration and waste exclusion
• How does the plasma membrane relate to organism systems?

  Closely related to nervous, respiratory, and digestive systems
• What is the significance of signaling in membrane transport?

  Generates ion gradients for signaling functions
• How does the thickness of the membrane affect permeability?

  Thicker membranes reduce permeability