Cell Structure and Function Chapter 5 Membrane Dynamics

Cell Structure and Function - Chapter 5 Membrane Dynamics 1. Using “X’s” draw a blood cell in a hypertonic environment. Which way is the water going to move? Why? Label ECF and ICF

Which cell is in a hypertonic environment?

Cell Structure and Function - Chapter 5 Membrane Dynamics Review Key Terms • • • Osmosis Diffusion ICF/ ECF Hypertonic/ Hypotonic/ Isotonic Be able to predict what will happen to water!

Diffusion across a membrane: Passive Transport No energy req’d down concentration gradient

Passive Transport: Facilitated Diffusion The passive movement of molecules down its concentration gradient via a transport protein is called facilitated diffusion Aquaporins

Facilitated Diffusion: Gated Ion Channels Some transport proteins do not provide channels but appear to actually translocate the solute-binding site and solute across the membrane as the protein changes shape.

Active Transport Requires E (ATP) Against the concentration gradient UPHILL!

Using The Gradient’s Energy HIGH concentration of H+ ions Chemiosmosis The movement of H+ ions down its concentration gradient is harnessed to the synthesis of ATP. What organelle? How can you concentrate the H+ ions? What protein is shown? LOW concentration of H+ ions

Through the Membrane

Transport with the Membrane E req’d In phagocytosis, the cell engulfs a particle by extending pseudopodia around it and packaging it in a large vacuole. In pinocytosis, “cellular drinking”, a cell creates a vesicle around a droplet of extracellular fluid Receptor-mediated endocytosis is very specific in what substances are being transported. This process is triggered when extracellular substances bind to special receptors, ligands, on the membrane surface, especially near coated pits. This triggers the formation of a vesicle