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“Materials move across the cell’s membranes”
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”
Membrane Components
• Phospholipids:– Gives the general structure of the membrane
Membrane Components
• Proteins: allow bigger substances to pass through, also provide structure
Membrane Components
• Cholesterol: helps maintain structure of phospholipids, prevents them from sticking
Membrane Components
• Carbohydrates: receptors that send and receive signals.
Simulation Activity
• Everybody Stand up!!! Lets make a membrane out of the desks.
• I need 4 volunteers (1-H2O, 3-Glucose)
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 a high concentration to a low concentration to create DYNAMIC EQUILIBRIUM.
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html
Effected By…
• Heat- higher temp increases rate
• State of Matter– Solid- slow– Liquid- faster– Gas- fastest
• Size and Concentration– Bigger= slower– More concentration = faster
Perfume Demo
Food Coloring Demo
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:
Solutions
- Solutions can be…- Isotonic- Hypertonic- hypotonic
Isotonic Solutions• Same amount of solute inside the
membrane as there is outside.
• Cell in this solution: NOTHING
Blood CellPlant Cell
11,397x
HYPERtonic Solutions
• More solute, less water
• Cell in this solution:shrinks/shrivels
“Plasmolysis”“Crenates”
HYPOtonic Solutions
• Less solute, more water
• Effect: cell swells or bursts! /
Do NowHigh or low Solute?
Cell in ________ Solution
Cell in ________ Solution
Cell in ________ Solution
H2
OH2
O
H2
OH2
OH2
OH2
O
Do NowWrite where there is high water
and high solutes.Cell in hypotonic Solution
Cell in isotonic Solution
Cell in hypertonic Solution
H2
OH2
O
H2
OH2
OH2
OH2
O
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?
2% Salt
3% Salt
12% Salt
9% Salt
28% Salt
18% Salt
A. B. C.
Scenario 3
• 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 )
Your garden is infested with slugs so you go around pouring salt on them
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?
DO NOW
• What type of solution is in the IV?
• What is going to happen to the cells of the human?
A patient is given an IV, which contains the perfect balance of glucose
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.
DO NOW
• What type of solution is the freshwater?
• What is going to happen to the cells of the fish?
A salt water fish is put into a freshwater aquarium.
For the following examples:
• A. Label the types of solutions inside the cell and outside the cell (hypertonic, isotonic, hypotonic)
• B. Where is the water going to move?
• C. What will happen to that cell? (Use vocab words!)
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