Passive Transport Type 1 Type 2 Type 3

Passive Transport Type 1 Type 2 Type 3 Definition: The process of substances passing through the cell membrane WITHOUT ANY INPUT OF ENERGY BY THE CELL. DIFFUSION Definition: Key Term: Solute molecules move from an area of high concentration to an area of low conc. Powered by the random motion of molecules. Equilibrium OSMOSIS Hypertonic: Solute conc. Bigr outside. H 2 O out Isotonic: Solute conc. = Inside & out. No net H 2 O change. Hypotonic: Solute conc. Lower outside. H 2 O in. Hypo-Hippo FACILITATED DIFFUSION Definition: Diffusion of water from an area of high H 2 O conc. (low solute conc. ) to low (high solute conc. ) Required for Ions (charged molecules) And Large Molecules Cell uses carrier proteins in membrane to allow the diffusion of molecules that can’t pass through membrane alone.

Active Transport • Active transport processes are different from passive ones: – Energy is required. – Substances move UP their concentration gradients from lower conc. to higher. – Equilibrium is PREVENTED.

Endocytosis • “Endo-” means in. • “cyto-” means cell. • “osis” means process of. • What does endocytosis mean? • Endocytosis: the process by which cells take in large amounts of material, by folding in the cell membrane

Endocytosis Example • Pinocytosis: non-specific endocytosis of small amounts of extracellular fluid. • Greek: “pino -” = “drinking”

Endocytosis Example • Phagocytosis: the endocytosis of solid particles such as bacteria, cell debris, or other solids • Greek: “phago-” = “eating”

Phagocytes • Phagocytes, such as some types of white blood cells, engulf foreign cells by phagocytosis.

For Protists, Phagocytosis = Eating

Exocytosis • Exocytosis is the same process as endocytosis, except in reverse. • The stuff leaving may be: – Proteins released into the ECF – New lipids for expanding the membrane – Membrane proteins – Chemicals for communication, etc. (e. g. dopamine)

Exocytosis

Endo and Exocytosis – quick review