“Materials move across the Cell’s membrane” Section 2.3

Do Now What is the purpose of the cell membrane in a cell? What goes in and out of our cells? Why are our membranes important?

Objectives To explain the different functions of the macromolecules in the plasma membrane. To understand the process of diffusion. To compare and contrast active and passive transport.

Membranes “Fluid Mosaic Model” Proteins and other components are embedded like a mosaic http://www.youtube.com/watch?v=Qqsf_UJcfBc

Membrane Components Phospholipids: Gives the general structure of the membrane

Draw a phospholipid and label its parts!!

Membrane Components Proteins: allow bigger substances to pass through Provide structure Microtubules and microfilaments (Cytoskeleton)

Membrane Components Cholesterol: helps maintain structure of phospholipids prevents them from sticking together!

Membrane Components Carbohydrates: receptors that send and receive signals. Attached to glyolipids and glycoproteins

Do Now What is diffusion? What is osmosis? How did you lab show osmosis happening?

Types of Transport across a cell membrane Passive Transport Active Transport Vesicular Transport

Passive Transport Do NOT require energy Go from an area of high concentration to an area of low concentration “Go with the flow”

3 Types of Passive Transport Diffusion Facilitated Diffusion Osmosis

Diffusion Molecules move from an area of high concentration to an area of low concentration . Trying to create DYNAMIC EQUILIBRIUM. (The same in all areas) http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

Affected By… Heat- higher temp increases rate State of Matter Solid- slow Liquid- faster Gas- fastest Size and Concentration Bigger= slower More concentration = faster

Explain what’s happening…

Do NOW Explain what happens when you put a sugar cube in your tea in regards to diffusion.

Objectives To understand how the process of Osmosis works. To explain the different types of solutions To compare and contrast endocytosis vs. exocytosis.

Facilitated Diffusion the molecules need a “helper” or “facilitator” to allow them to cross the membrane when they are too big.

Osmosis The flow of WATER from a high concentration to a low concentration Occurs based on the types of solutions you are working with.

Solution A) a mixture in which you cannot separate the components (ex: Kool aid) i. solute: the substance being dissolved Ex: kool aid powder Ii. solvent: The substance doing the dissolving Ex: water

Do Now I like to make ice tea using ice mix and water. Identify the: 1. Solute: 2. Solvent: 3. Solution:

Isotonic Solutions Same amount of solute inside the membrane as there is outside. Cell in this solution: NOTHING  Plant Cell Blood Cell 11,397x

HYPERtonic Solutions More solute, less water on the outside of the membrane. Cell in this solution: shrinks/shrivels  “Plasmolysis” “Crenates”

HYPOtonic Solutions Less solute, more water on the outside of the membrane. Effect: cell swells or bursts! /

Do Now High or low Solute? Cell in ________ Solution Cell in ________ Solution Cell in ________ Solution H2O H2O H2O

Answer key! Write where there is high water and high solutes. Cell in hypotonic Solution Cell in isotonic Solution Cell in hypertonic Solution H2O H2O H2O

Do Now For the following examples: Which way is the water moving? What kind of cell solution (outside)? What is going to happen to the cells? A. B. C. 12% Salt 9% Salt 28% Salt 18% Salt 2% Salt 3% Salt

Scenario 1 Your garden is infested with slugs so you go around pouring salt on them What type of solution is this salt? What is going to happen to the cells of the slug? (don’t do this to the poor slugs )

Scenario 2 A patient is given an IV, which contains the perfect balance of glucose What type of solution is in the IV? What is going to happen to the cells of the human?

A salt water fish is put into a freshwater aquarium. Scenario 3 A salt water fish is put into a freshwater aquarium. What type of solution is the freshwater? What is going to happen to the cells of the fish?

Practice By yourself or with a partner (anyone), work on the diffusion problems. First try to do this by yourself, then verify your answers with a partner. Try to help each other. If you are confused, raise your hand and I will come help you!! If you finish early, please pick up a copy of your homework. THIS WILL BE GRADED.

Do Now What is passive transport? What is an isotonic solution? What is a hypertonic solution? What is a hypotonic solution?

Objectives To compare and contrast active transport vs. passive transport To explain the process of endocytosis and exocytosis To determine the difference between pinocytosis and phagocytosis.

Active Transport when molecules move from a low concentration to a high concentration and must use ENERGY. Example- Sodium Potassium Pump http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html

Vesicular Transport Sometimes things enter and exit the cell by forming vesicles. For example… Endocytosis: When cells absorb molecules by engulfing them. (like pacman)

Endocytosis Pinocytosis: when the substance being engulfed is a LIQUID. Phagocytosis: when the substance being engulfed is a SOLID.

Vesicular Transport Exocytosis: When cells expel unwanted materials from vesicles.

Vesicular Transport http://highered.mcgraw-hill.com/olc/dl/120068/bio02.swf