“Materials move across the cell’s membranes” Section 2.3

“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