Osmosis, Diffusion & Active Transport L/O: To review understanding of diffusion, osmosis and active transport and how to investigate the process of osmosis Starter Recap: Write your own definition of diffusion on the whiteboard Extension: Explain how nutrient get from inside the small intestine to the blood stream CORE: Independent Enquirers Success Criteria: A* - Suggest how to investigate the rate of osmosis A – Explain the process of osmosis and its primary functions, and how these differ from diffusion and active transport B – Describe the steps in osmosis C – State what is involved in diffusion KEY WORDS Osmosis Solute Partially permeable membrane particle diffusion concentration gradient Active transport

If you open a can of pop, gas particles spread out into the air. This is another example of diffusion. Diffusion is the movement of particles from an area of high concentration, to an area of lower concentration. Definition:

Osmosis Solute molecule Many water molecules Weak Solution Strong Solution Fewer water molecules Partially permeable membrane What will happen in this situation?

Osmosis in blood cells Liquid is more concentrated Liquid and cell cytoplasm are the same concentrations Inside cells are more concentrated flaccid Cells become flaccid when water moves out of them. turgid Cells become turgid due to water pressure when water moves into them

Osmosis vs. Diffusion What are the similarities and differences between the two? SimilaritiesDifferences

Osmosis vs. Diffusion: PEER ASSESS What are the similarities and differences between the two? SimilaritiesDifferences Movement of molecules from areas of high concentration to low concentration Movement of small particles/molecules Both found in all plant and animal cells to move substances in and out Osmosis is movement of water only/ Diffusion any small molecules Osmosis moves across a partially permeable membrane/ Diffusion moves more generally

How to kill a slug? QUESTIONS: Using your knowledge of osmosis explain how to remove the slugs that are eating Farmer Gile’s lettuces! Include an explanation using the following key words: Concentration gradient Osmosis Diffusion Solute Particle

Active Transport This is when substances are absorbed against their concentration gradients. This uses energy. Explain how this process uses active transport and where this might be found.

OSMOSIS Recap both directions Water molecules move in both directions Net flowhigh concentrations water molecules low concentrations water molecules Net flow of water is from areas of high concentrations of water molecules to low concentrations of water molecules partially permeable membrane large Sugar cannot cross the partially permeable membrane as they are too large Net flowdilute solutions concentrated solutions Net flow of water is from dilute solutions to concentrated solutions

Cold Call Questions! 1.What is an independent variable? 2.What is a dependent variable? 3.What is a systematic error? 4.What makes something reliable? 5.What makes something valid? 6.What is diffusion? 7.Give an example of diffusion? 8.What is osmosis? 9.What is different about osmosis and diffusion? 10.Name one place in the body where diffusion happens? 11.What happens to a red blood cell if it is placed in a salt solution? 12.What happens to a red blood cell if placed in a pure water solution?

THE EXPERIMENT 1.Weigh 4 different 1cm 3 of potato cube on scales (RECORD EACH WEIGHT) 2.Place each potato chip into a boiling tube with different sugar solutions 3.Leave for 20mins and complete questions while waiting! 4.Remove chips, dry and re-weigh. 5.Calculate the change in mass of each chip in each concentration Method:

THE EXPERIMENT Method: Label the potato boiling tube so you know which cube is which! Complete the workshe et while you are waiting for the results!

DRAWING A TABLE Solution sugar concentration (%) Initial Mass (g)Final Mass (g)Change in mass (g)

INTERPRETING RESULTS Change in mass of potato (g) Sugar solution (%) Plot a graph of your results and explain what happens at each stage

What have I learnt? A* - Success Criteria: A* - Suggest how to investigate the rate of osmosis A – Explain the process of osmosis and its primary functions, and how these differ from diffusion and active transport B – Describe the steps in osmosis C – State what is involved in diffusion On the exit ticket complete what target you archived you know you achieved (i.e. what can you do). Look at the success criteria to help you 5 min