Syllabus update: Switch today (11/19) and tomorrow (11/20) Do Now 11.19 OBJECTIVES:1. Identify three ways that active transport is different from passive transport. 2. Define endocytosis and exocytosis. 3. Describe the function of the sodium-potassium pump as an example of active transport. TASK: One curve represents the diffusion of glucose through the lipid bilayer, and the other represents the transport of glucose by facilitated diffusion. Which curve corresponds to facilitated diffusion? Explain your reasoning. TASK2: Syllabus update: Switch today (11/19) and tomorrow (11/20)

Passive Transport Definition: Type 1 Type 3 Type 2 DIFFUSION OSMOSIS The process of substances passing through the cell membrane WITHOUT ANY INPUT OF ENERGY BY THE CELL. Passive Transport Type 1 Type 3 Type 2 DIFFUSION OSMOSIS FACILITATED DIFFUSION Definition: Solute molecules move from an area of high concentra-tion to an area of low conc. Powered by the random motion of molecules. Key Term: Equilibrium Definition: Cell uses carrier proteins in membrane to allow the diffusion of molecules that can’t pass through membrane alone. Hypertonic: Solute conc. Bigr outside. H2O out Definition: Diffusion of water from an area of high H2O conc. (low solute conc.) to low (high solute conc.) Required for Ions (charged molecules) Isotonic: Solute conc. = Inside & out. No net H2O change. And Hypotonic: Solute conc. Lower outside. H2O in. Hypo-Hippo Large Molecules

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

The Sodium / Potassium Pump The Na+/K+ pump is responsible for maintaining the electrical charge of a cell Cells are negative Communication, e.g. neurons Cation uptake It is an example of a membrane pump which move specific things into or out of the cell AGAINST THEIR CONCENTRATION GRADIENT. Since it requires energy, it is an example of ACTIVE TRANSPORT!

How the Na+/K+ Pump Works Don’t forget the animation….

Na+/K+ Pump… Drake demonstrates…

Recap: Active Transport Uses ATP Active transport is different from passive in 3 key ways (energy, up gradient, no equilibrium) Endocytosis = cell taking in material by infolding the membrane. Pinocytosis = “cell drinking” ECF Phagocytosis = “cell eating” bacteria, etc. Exocytosis = cell exporting materials in bulk. Na+/K+ Pump = an example of a membrane pump moves 3 Na+ out and 2 K+ in per cycle. Causes cells to be negatively charged.