Diffusion and osmosis LT 6.10.4 SWABT describe and compare different mechanisms of substance transport into and out of cells (e.g. diffusion, osmosis,

Diffusion and osmosis

LT 6.10.4 SWABT describe and compare different mechanisms

of substance transport into and out of cells (e.g. diffusion, osmosis, passive and active transport)

Do gummy bears grow up?

Have you ever bought a bag of gummy bears?

Are all gummy bears approximately the same size?

Do gummy bears grow up?

Let’s check this out!!

Hands on activity

• Here are your gummy bears!• Your job will be to PREDICT & OBSERVE what

happens to your gummy bears when you merge them into water

• First, make a prediction: what does it happen to the gummy bears if you put them in water?

• Then, record the weight of your gummy bear

Possible questions

• Does the color affect what is going to happen to the gummy bear?

• Is the color going to dissolve?• Will the size of gummy bear change in water?• Make a prediction• Discuss it with your partner

Diffusion and Osmosis

Diffusion and Osmosis

• Passive transports: diffusion (simple & facilitated) and osmosis

• Active transport

Materials move across membranes because of concentration differences.

Diffusion and Osmosis

Passive transport does not require energy input from a cell.

• Molecules can move across the cell membrane through passive transport.

• There are two types of passive transport.

• osmosis

• diffusion

Diffusion and Osmosis

Molecules move from high to low concentration

• Diffusion– move from HIGH to LOW concentration

Diffusion• Move from HIGH to LOW concentration

– passive transport– no energy needed

diffusion

Simple Diffusion • Move from HIGH to LOW

inside cell

outside cell

Which way will fat move?

fat

fat

fat

fat

fat

fat fat

fatfat

fat

fat

fat

fat

fat

LOW

HIGH

Facilitated Diffusion• Move from HIGH to LOW through a channel

inside cell

outside cell

sugar

sugar

sugar

sugar

sugarsugar

sugarsugar

sugarsugar

sugar

Which way will sugar move?

sugar

sugar

LOW

HIGH

Diffusion - Summarize• Move from HIGH to LOW concentration

– directly through membrane• simple diffusion• no energy needed

– help through a protein channel• facilitated diffusion (with help)• no energy needed HIGH

LOW

Simple vs. facilitated diffusion

inside cell

outside cell

lipidinside cell

outside cell

H2O

simple diffusion

facilitated diffusion

H2O

protein channel

Active transport• Cells may need molecules to move against

concentration gradient– need to pump “uphill”

• from LOW to HIGH using energy

– protein pump– requires energy

• ATP

ATP

Transport summary

simplediffusion

facilitateddiffusion

activetransport

ATP

Osmosis

• Movement of WATER into a region of higher solute concentration

osmosis

diffusion of water

Osmosis (diffusion of water)

• http://www.youtube.com/watch?v=sdiJtDRJQEc

White board

• What’s the main difference between passive and active transport?

White board

• How many types of passive transport do you know?

White board

• Describe the facilitated passive transport• Why is it called “facilitated” passive transport?

White board

• What are protein channels?

White board

• Describe active transport

White board

• What is osmosis?

White board

• Is osmosis a passive or active transport mechanism?

• There are three types of solutions.

• isotonic

Diffusion and Osmosis

• hypotonic

• hypertonic

Isotonic solution

Hypertonic solution

Hypotonic solution

Keeping water balanceCell survival depends on balancing water

uptake & water loss

freshwater balanced saltwater

J-TPS

Can you reverse the process? How?