Warm up 10/15 Draw a plasma membrane & Include the following Label correct parts of the phospholipids hydrophobic and hydrophilic. Integral proteins Peripheral proteins Cholesterol What does semi-permeable mean?

Chapter 4- 5: Notebook #9 (Ws #1: Notebook #8) Textbook pg. 97-102 PASSIVE TRANSPORT Chapter 4- 5: Notebook #9 (Ws #1: Notebook #8) Textbook pg. 97-102

Solutions 2 Parts: Concentration: A measure of how much solute per unit of solvent ex/ 200mg NaCl / mL H20 Solution = Solute (that which is dissolved) + Solvent (the liquid that does the dissolving) These glasses containing red dye demonstrate qualitative changes in concentration. The solutions on the left are more dilute, compared to the more concentrated solutions on the right.

Passive transport Movement across the cell membrane without energy. What characteristic does the cell membrane have?

Diffusion Movement of molecules from area of high concentration (CONC) to area of low concentration

Concentration Gradient Molecules have kinetic energy Concentration Gradient: difference between high and low concentration Molecules move “down” gradient. Molecules move until they reach equilibrium (when all molecules are evenly spread out).

Osmosis Osmosis: special diffusion of water across membrane A solution is made of a solute dissolved in a solvent (like water). Direction of movement is dependent on solutes outside cell.

Hypotonic Concentration of solutes is lower outside the cell and water moves into the cell  cell swells

Hypertonic Concentration of solutes is higher outside the cell and water moves out the cell  cell shrinks

Isotonic: Concentration of solutes inside = outside  so no water moves

Facilitated Diffusion Molecules too big to move across the membrane use carrier proteins Ex. Glucose

CELL DIVERSITY AND CELL SIZE Chapter 5 pg. 72-73

Cell shape Cell shape related to function of the cell

Cell size Surface area to volume ratio decreases with increasing cell size (EX. 6:1 vs 3:1) Volume increases quicker than the surface area

Summary of the Mini-Lab What was different about the 3 cubes? What happened when we placed the cubes (model cells) in the solution of NaOH? Did the NaOH diffuse the same distance?

Why is this important to the cell? Substances cannot get to the center, or out of the center of the cell if it’s too big

What does this mean for the cell? The bigger the volume the less surface area not enough surface area to meet the needs of the increasing volume distance to center increases as cell increases Difficulty exchanging materials (such as nutrients, oxygen, and waste products) across the cell

ACTIVE TRANSPORT Chapter 5 pg. 103-106

Active Transport Requires energy Molecules move from an area of low concentration to an area of high concentration Move against the concentration gradient

Membrane pumps

Carrier proteins that are active are called pumps. Protein binds to a specific molecule. Protein transfers the molecule to the other side. Sodium-Potassium Pump: transports Na+ and K+ against (not down) gradient 3 Na+ out and 2 K+ in

Endocytosis and Exocytosis Used to move very large molecules in and out of the cell

Endocytosis Ingest large molecules into cell Material is engulfed by cell membrane. Membrane makes a pouch. Pouch then pinches off and makes a vesicle. Vesicle binds with lysosome.

Phagocytosis A form of endocytosis in which immune cells attack and ingest bacteria

Exocytosis (the reverse of endocytosis) moving large particles out of the cell