Cell Biology Quest 2 notes

o   What are the seven major functions of membranes?

o   Describe the experiment that first revealed that the plasma membrane was a lipid bilayer.

o   The fluid-mosaic model is the prevailing current model for the plasma membrane.  Describe this model.

o   What are the primary components of membranes?  How does this vary among different cell types? Among different organelles of the same cell?

o   What does amphipathic mean?

o   Name and describe the three main types of membrane lipids.  What are properties of each?

o   What is a liposome?

o   What is a stealth liposome? What is the application?

o   Why is it important that membranes are fluid?

o   Why are the inner and outer membrane leaflets different?

o   How is ABO blood typing related to the membrane?  What kinds of blood can you give to patients and why?

o   Describe the three classes of membrane proteins.

o   What does Freeze-fracture analysis show?  How is it performed?

o   How would you solubilize an integral membrane protein?

o   What types of amino acids are typically found in transmembrane domains?

o   What is a hydropathy plot?

o   Describe how you could use site-directed mutagenesis to identify spatial relationships within and between proteins.

o   What factors influence membrane fluidity?

o   What are lipid rafts?  Why are they controversial?

o   Describe an experiment that shows the dynamic nature of proteins within the plasma membrane.

o   Why do proteins move more rapidly in artificial membranes versus real cellular membranes?

·       Membrane Transport

o   What are the four basic mechanisms by which solute molecules move across the membrane?

o   What is the difference between diffusion and active transport?

o   What is the partition coefficient?  What does it determine?

o   What is osmosis?

o   What happens to a cell when placed in a hypotonic solution? How about a hypertonic solution?  An isotonic solution?

o   When might a plant cell undergo plasmolysis?

o   What are aquaporins?

o   What is turgor pressure?

o   What is the permeability of the membrane for ions? Water? Macromolecules?  Small, uncharged molecules?

o   What are some properties of ion channels?

o   What do patch clamping experiments show?

o   What does it mean that most ion channels are gated?

o   What are 3 types of ion channels?

o   Describe in detail how the voltage-gated potassium channel works.

o   Describe facilitated diffusion using the glucose transporter as an example.

o   Describe active transport using the Na+/K+ ATPase as an example.

o   What is a P type pump?  Name an example.

o   What is a V type pump?

o   What is an ATP-binding cassette protein?

·       Membrane Potentials and Nerve Impulses

o   What is a membrane potential?

o   What is a resting potential?

o   What types of cells have a resting potential?

o   What is a neuron?

o   Name the parts of a typical neuron and their functions.

o   How are K+ gradients across the membrane maintained?

o   Which ions (Na+, K+, Cl-, Ca++) are typically more concentrated inside the cell versus outside?

o   How is an action potential generated?  What happens in the stages of an action potential?

o   Excitable membranes exhibit all-or-none behavior.  What does this mean?

o   The speed of a nerve impulse depends primarily upon what two criteria?

o   Describe the propagation of an impulse for a non-myelinated and myelinated neuron.

o   What is a synapse?

o   Describe the importance of neurotransmitters.

o   How is neurotransmitter action terminated?

o   Describe impulse transmission with acetylcholine as the neurotransmitter.

o   How do different cone snail toxins affect impulse transmission?  See HHMI animations.