04 December 2020 The role of diffusion Learning

04 December 2020 The role of diffusion 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.