Diffusion and osmosis LT 6 10 4 SWABT

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

Diffusion and Osmosis 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. • diffusion • 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 fat inside cell fat LOW fat fat Which way will fat move? HIGH fat outside cell fat fat

Facilitated Diffusion • Move from HIGH to LOW through a channel sugar inside cell sugar sugar LOW Which way will sugar move? HIGH outside cell sugar sugar

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 simple diffusion inside cell lipid facilitated diffusion inside cell H 2 O protein channel outside cell H 2 O

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