1. Active Transport Requires use of energy because it does not happen naturally through diffusion or facilitated diffusion. Requires a carrier protein* that uses energy from ATP molecules (Adenosine Tri-Phosphate, a nucleotide that stores energy and can release it when bonds are broken.) Why? Moving stuff against the concentration gradient requires a “pump”. OR Fusing/rebuilding of cell membranes

2. Compare Membrane Proteins Active Transport vs. Facilitated Diffusion : Both use…. Carrier Proteins But only active transport carrier proteins require… ATP Because they need energy to change their shape!

3. ATP Sodium – Potassium Pump Phospholipid Bilayer Na+ Phosphates from ATP breakdown K+

4. Active Transport - Bulk Transport One large or many small particles moved in or out of cell using membrane bubbles called vesicles that can fuse with the cell/plasma membrane Exocytosis – materials moved out of cell Ex.: secretion of tears & sweat

5. Active Transport - Bulk Transport Endocytosis – materials moved into cell Phagocytosis – “cell eating”  solid particle(s) taken in Ex.: phagocytes such as macrophages & other immune cells ingesting bacteria Pinocytosis – “cell drinking”  liquid/many small particle(s) taken in Ex.: Cells “gulping up” plasma from blood, leaving RBCs in blood

7. Endocytosis? Exocytosis? # 2 # 1 #3

8. Endocytosis 1. Pinocytosis 2. Phagocytosis

9. Contractile Vacuole ‘Sump Pump’ in unicellular aquatic organisms Environment is 99% Water Cell is 95% Water Active or Passive?