The role of diffusion Saturday, 03 August 2019 Learning objectives: To collect data and analyse it to explain the connection between surface area and rate of diffusion.

Starter (5 mins) Prediction about how big the biggest cell in the world is???

Nerve cell 12 metres in length! However, despite their length they are still only around 0.5 mm in width.

Cells need water, oxygen and other substances in order to carry out processes such as respiration. Some substances are able to travel through the cell membrane by a process called diffusion.

Animal cell

Work in pairs. Practicals and Investigations sheet ‘Jelly cells and diffusion’. Read through the sheet and complete the risk assessment, then decide on the sizes they will use for the cubes and design a results table. After going through some of their ideas, and checking they understand the method, allow the students to proceed with the investigation.

Once they have gathered results, students should plot line graphs to display their results and write a conclusion using the information on the practical sheet.

Diffusion is when particles move from one area to another. They move from a high concentration to a low concentration.

Plenary (5 mins) Explain why individual cells must stay small. Use the words: diffusion, cell membrane and surface area in their answer.