Guiding Questions
Membrane Structure
- Explain why phospholipids are amphipathic molecules.
- Explain what freeze-fracture techniques reveal about the arrangement of proteins in membranes.
- Describe the fluidity of the components of a cell membrane and explain how membrane fluidity is influenced by temperature and membrane composition.
- Explain how cholesterol resists changes in membrane fluidity with temperature change.
Traffic across Membranes
- Distinguish between peripheral and integral membrane proteins.
- List six major functions of membrane proteins.
- Explain the role of membrane carbohydrates in cell-cell recognition.
- Explain how hydrophobic molecules cross cell membranes.
- Distinguish between channel proteins and carrier proteins.
- Define diffusion. Explain why diffusion is a spontaneous process.
- Explain why a concentration gradient of a substance across a membrane represents potential energy.
- Distinguish among hypertonic, hypotonic, and isotonic solutions.
- Define osmosis and predict the direction of water movement based on differences in solute concentrations.
- Describe how living cells with and without cell walls regulate water balance.
- Explain how transport proteins facilitate diffusion.
- Distinguish among osmosis, facilitated diffusion, and active transport.
- Describe the two forces that combine to produce an electrochemical gradient.
- Explain how an electrogenic pump creates voltage across a membrane.
- Describe the process of cotransport.
- Explain how large molecules are transported across a cell membrane.
- Distinguish between pinocytosis and receptor-mediated endocytosis.
