This is a picture of the experiment “Shaping Up – the relationship between shape and diffusion”. It shows the agar stained with phenolphthalein indicator, which turns clear in acid. When the different size and shaped agar blocks are placed in an acid solution, the aicd diffuses into the jelly, causing to change from pink to clear. The time taken for a block to totally decolourise is a measure of the rate of diffusion of acid into the jelly. We will be doing this experiment on Friday, during periods 1 and 2.
Please make sure you have read all of chapters 1 and 2 and finished all the relevant Chapter Review questions. If you have finished this work, you can start reading chapter 3 “Composition of Cells” (pages 52 to 73). This chapter is designed for you to develop a knowledge and understanding of the composition of cells, understand the relationship between the nature of various substances found in cells and the functions they perform in those cells and learn more about inputs and outputs, enzymes and biochemical processes.