Edexcel IGCSE Biology 2.17 Diffusion & osmosis practical

Practise diffusion and osmosis practical work with potato tissue, sucrose solutions, dialysis bags, ammonia diffusion, graphs and rate calculations.

Exam points

identify independent or dependent variables in diffusion and osmosis practicals
plot line graphs with correct axes, units, scales and joined data points
calculate diffusion rate or describe mass changes from practical results

[Maximum number: 2]

The image shows some cells from onion epidermis.

Figure for Question 2.17 Diffusion and osmosis practical question 1 — Edexcel IGCSE Biology

The images show samples of red onion epidermis cells before and after being placed into a 5\% sucrose solution for one hour.

Before

After

Describe how to make $10 \mathrm{~cm}^{3}$ of a 5% sucrose solution from a 10% sucrose solution and pure water.

A description that makes reference to the following:

- use a syringe / pipette / beaker / (measuring) cylinder / eq

- mix $5\left(\mathrm{~cm}^{3}\right)$ of ( $\left.10 \%\right)$ sucrose solution with $5\left(\mathrm{~cm}^{3}\right)$ water / eq

Accept other correct measuring apparatus

Accept take $5\left(\mathrm{~cm}^{3}\right)$ sucrose and make up to $10\left(\mathrm{~cm}^{3}\right)$ with water / add equal volumes of water and sucrose and use $10\left(\mathrm{~cm}^{3}\right) /$ eq

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2.17 Diffusion and osmosis practical question 1