Solution

1. Solution • Fluid environment on both sides of the plasma membrane is a solution • A mixture where the particles are evenly distributed

2. Solute • What is being dissolved in the solution

3. Solvent • What is doing the dissolving in the solution • Water is the most common solvent, due to its polarity

4. Membrane Transport • Passive -Difffusion -osmosis -facilitated diffusion -Filtration • Active -Na+/K+ pump -Endocytosis and Exocytosis

5. Diffusion • Movement of molecules from a greater to a lesser concentration • Ex: Smells from dinner in the kitchen gradually reach the other side of the house

6. Osmosis • Movement of WATER molecules from a greater to a lesser concentration • The movement occurs through a selectively permeable membrane • Ex: A cell

7. Isotonic Solution • Having equal concentrations inside and outside

8. Hypotonic Solution • Hypo means less • Has a lower concentration of solute (what dissolved in the water) • Has greater concentration of water

9. Hypertonic solution • Hyper means more, higher • Has greater concentration of solute • Has less concentration of water

10. Facilitated Diffusion • Protein carrier is needed as a transport vehicle (proteins in the plasma membrane) • For molecules that are too large or lipid-insoluble to pass through the plasma membrane • Concentration gradient still in force

11. Filtration • Water and solutes are forced through a membrane by fluid or hydrostatic pressure (exerted by the blood) • Gradient is involved, but it is a pressure gradient instead of concentration • Not very selective, since only molecules too large to pass are held back • Ex: kidneys form filtrate (urine)

12. Solute Pumping (Na+/K+ Pump) • Use of ATP to energize protein carriers (as opposed to kinetic energy in passive transport) • Amino acids, some sugars, and most ions are transported this way • Movement is against concentration gradient • Very selective

13. Exocytosis and Endocytosis • Substances are moved out of the cell • Ex: hormones, mucus, cellular waste • Small membrane sacs produced by the Golgi apparatus to carry substances • Sacs move to plasma membrane, fuses with it, then ruptures, spilling the contents out of the cell • Endocytosis is the reverse process

14. Pinocytosis and Phagocytosis • Two types of endocytosis • Pinocytosis is “cell drinking”, taking in liquids that contain fats or proteins • Especially found in cells that function in absorption (small intestine and kidney tubule cells) • Phagocytosis is “cell eating”, taking in large bacteria or dead body cells • Phagocytes (WBC) act as scavengers