19 Facilitated Diffusion Use of carrier proteins the assist diffusion across a membrane.Specific carrier proteins for specific molecules (like glucose or amino acids)“Down the gradient”
20 Diffusion via ion channels Use of membrane proteins to assist diffusion of ions across a membraneChannel is usually specific to 1 type of ionCommon ions:SodiumPotassiumChlorineCalcium
21 Notebook Quiz Osmosis is the diffusion of _____________. During diffusion, molecules tend to move in what direction?Does the movement of molecules stop once equilibrium is reached? Explain.What is the function of carrier proteins?If the external solution is hypotonic compared to the cell, which direction will water move?
23 Active TransportUses energy (ATP) to move materials against the gradient“Up the gradient”Low to high concentration
24 1. Sodium Potassium PumpTransports sodium and potassium ions across the membrane up their gradientsLow to high concentrationUses ATP
25 2. Endocytosis Movement of large amounts of material into the cell Formation of a vesicle from the cell membrane that will go to the lysosome for digestionUses ATP
26 2 types of endocytosis 1. pinocytosis: “cell drinking” Transport of a large quantity of liquid into the cell2. phagocytosis: “cell eating”Transport of a large quantity of solids into the cellUses ATP
27 Moving the “Big Stuff”Large molecules move materials into the cell by one of three forms of endocytosis.
28 3. ExocytosisThe movement of a large amount of materials out of the cellVesicle fuses to the cell membrane to release contents out of the cellUses ATP
29 ExocytosisExocytic vesicle immediately after fusion with plasma membrane.