The Cell MembraneOsmosis and Diffusion

The Plasma (Cell) Membrane

- Flexible boundary- Allow entry and exit of

materials- Surface markers- Selectively permeable/semi-

permeable - Phospholipids- Fluid mosaic model

Channel Protein

Cell

Membrane

Lipid

Outside of Cell

Inside of Cell

Marker Protein

ReceptorProtein

Carbohydrate chain

Cells move substances through the cell membrane

by a process called transport

Two Types of Transport:

Passive Transport

Active Transport

What is Passive Transport?

Requires no energy from cell.

Molecules move from high concentration to

low concentration.

Molecules move with the concentration gradient.

What’s happening?

How would diffusion happen in a cell?

Osmosis is a type of diffusion

Cell Membrane

HELP WANTED!

I’m a Channel, I can help!

Explain what is happening

Cellular Transport and Osmosis

- Maintaining homeostasis/equilibrium

- Hypertonic solution – low water- Hypotonic solution – high water,

lyses- Isotonic solution – equal solutions

What would happen to the animal cells in each beaker?

100% Distilled Water

80% H2O

70% Water30% Dissolved

Substances

80% H2O

80% Water20% Dissolved

Substances

80% H2O

Which way did the water move?

100% Distilled Water

80% H2O

Why did the cell get so big?

Which way did the water move?

80% Water20% Dissolved

Substances

80% H2O

Why did the cell stay the same

size?

Which way did the water move?

70% Water30% Dissolved

Substances

80% H2O

Why did the cell get so small?

How is Active Transport different?

1. Active transport requires energy.

2. Molecules move from low concentration to high concentration

3. Molecules move against concentration gradient.

Which way would the solute be moving if this were active

transport?

90% Water

80% H2O

Why would it move that direction?

Types of Transport

- Passive transport- Diffusion – molecules from high to low- http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/

animation__how_diffusion_works.html

- Osmosis – water from high to low- http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/

animation__how_osmosis_works.html

- Active transport- http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/

animation__how_facilitated_diffusion_works.html

- Endocytosis – taking in- Phagocytosis – solids- http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/

animation__phagocytosis.html

- Pinocytosis - liquids- Exocytosis

- removal