7.3 Cell Membrane and Osmosis/Diffusion

phospholipid bilayer

two sheets of phospholipids in a cell membrane, passive transport diffusion

peripheral protein

protein not "embedded" in phospholipid bilayer, helps with transport and communication

integral proteins

protein that is embedded in phospholipid bilayer, helps channel and transport molecules across phospholipid bilayer

channel protein

integral protein that does facilitated diffusion (facilitated transport)

carrier protein

integral protein that does active transport using ATP

gradient of concentration

used to describe concentration of solvent and solute

solvent

dissolves (water, etc)

solute

gets dissolved (salt, sugar, etc)

exocytosis

cell vacuole expels large amounts of material

endocytosis

cell vacuole intakes large amounts of material

phagocytosis

endocytosis of large solids (amoeba eating cell, etc)

pinocytosis

endocytosis of extracellular fluids

diffusion

the spreading out of molecules from high concentration to low concentration

osmosis

diffusion of solvent (water) through selectively permeable membrane

facilitated diffusion

when only specific molecules can pass through selectively permeable membrane, which speeds up diffusion (NO ENERGY USED)

isotonic solution

solute/solvent ratio equal compared to cell (cell remains same)

hypertonic solution

more solute compared to cell (water leaves cell, cell shrinks)

hypotonic solution

less solute compared to cell (water enters cell, cell expands)

cholesterol

helps phospholipid bilayer resist structure change caused by temperature changes

protein pumps (ion pumps)

moves ions against concentration gradient using ATP

sodium-potassium pump

3 Na+ (sodium ion) pumped out for every 2 K+ (potassium) pumped in

cotransport

coupling the transport of molecules through cell membrane

sodium-glucose symport

couples transport of sodium ions and glucose into cell

proton pump

remove hydrogen ions (H+)

glycoprotein, glycolipid, and carbohydrates

on the outside of phospholipid bilayer, used for messaging and cell identification