Cell Biology (B1)

There's no right or wrong answer - this just helps us see how you're getting on. Pick the one that feels closest.

1. Place a cutting mat on the bench before using any sharp equipment.
2. Use a cork borer to push through the potato and remove a cylinder of tissue.
3. Use a scalpel to trim each cylinder to the same length on the cutting mat.
4. Repeat until you have 6 cylinders of equal length.
5. Use a measuring cylinder to add equal volumes of each solution to six labelled boiling tubes.
6. Blot each cylinder dry with paper towel, then record its initial mass on the balance.
7. Place one cylinder into each tube. Start the stopwatch immediately.
8. After 25–30 minutes, remove each cylinder and blot it dry.
9. Record the final mass of each cylinder.
10. Calculate % change = (final − initial) ÷ initial × 100 for each cylinder.
11. Plot concentration (x-axis) vs % change in mass (y-axis). Draw a line of best fit.

1. Peel a thin, transparent layer from the inner surface of an onion using forceps.
2. Place the tissue flat on a clean glass slide.
3. Add one drop of iodine solution to stain the cells.
4. Carefully lower a coverslip at an angle to avoid air bubbles.
5. Place the slide on the microscope stage and clip it in place.
6. Start on the lowest power objective lens.
7. Use the coarse focus knob to bring the cells roughly into view.
8. Switch to a higher objective lens.
9. Use the fine focus knob to sharpen the image.
10. Make a scientific drawing of what you see, labelling cells and recording the magnification.