Required Practicals

• Photosynthesis experiment


  1. Take a boiling tube and place it 10cm away from an LED source

  2. Fill the boiling tube with sodium hydrogen carbonate solution

  3. Put a piece of pondweed into the boiling tube with the cut end at the top

  4. Leave for 5 minutes to acclimatise

  5. Observe bubbles of gas being produced

  6. Cut the end of the pondweed

  7. Start a stopwatch and count the number of bubbles produced in 1 minute

  8. Repeat 2 more times to calculate the mean

  9. Repeat the experiment at different distances from the LED source (20cm, 30cm, 40cm)

  10. Place the pondweed under a funnel and catch the bubbles in a measuring cylinder to measure the volume of oxygen gas produced
• Osmosis experiment


  1. Peel a potato

  2. Cut the potato into 3 cylinders of the same diameter

  3. Use a scalpel to cut the cylinders to the same length (3cm)

  4. Measure the length and mass of each cylinder

  5. Place each cylinder into a test tube

  6. Add 10cm³ of 0.5 molar sugar solution to the first test tube

  7. Add 10cm³ of 0.25 molar sugar solution to the second test tube

  8. Add 10cm³ of distilled water to the third test tube

  9. Leave overnight for osmosis to occur

  10. Remove the cylinders, dry them on paper, and measure their new length and mass
• Microscope


  • Stage - holds the microscope slide
  • Lamp (below stage) - mirror reflects light up through the microscope slide
  • Lenses - objective lenses have a magnification of 4x, 10x or 40x, eyepiece lens has a magnification of 10x
  • Coarse focusing dial - adjusts focus roughly
  • Fine focusing dial - brings the cell into clear focus
• Iodine solution test for starch


  1. Add one drop of iodine solution into each well of a spotting tile

  2. Prepare 3 test tubes - one with 2cm³ of starch solution, one with 2cm³ of amylase solution, and one with 2cm³ of pH 5 buffer solution

  3. Place all 3 test tubes in a water bath at 30°C for 10 minutes

  4. Combine the 3 solutions into one test tube and mix with a stirring rod

  5. Return the test tube to the water bath and start a stopwatch

  6. After 30 seconds, use the stirring rod to transfer one drop of the solution to a well in the spotting tile containing iodine

  7. Repeat this every 30 seconds until the solution remains orange, indicating starch is no longer present

  8. Repeat the experiment with different pH buffers (6, 7, 8)
• Food testing for starch, sugars and proteins


  1. Grind the food sample with distilled water using a mortar and pestle to make a paste

  2. Transfer the paste to a beaker and add more distilled water to dissolve the chemicals

  3. Filter the solution

  4. Place 2cm³ of the food solution in a test tube and add drops of iodine solution - blue-black indicates starch is present

  5. Add 10 drops of Benedict's solution to 2cm³ of the food solution, place in a water bath at 60°C for 5 minutes - green, yellow or red indicates the presence of reducing sugars

  6. Add 2cm³ of biuret solution to 2cm³ of the food solution - purple/violet indicates the presence of proteins

  7. Grind the food with distilled water using a mortar and pestle, do not filter - add a few drops of ethanol, a cloudy emulsion indicates the presence of lipids/fats
• Safety goggles must be worn when conducting experiments
• Increasing temperature increases kinetic energy, which can increase reaction rate but also denature proteins (unfolding).
• The purpose of this practical is to investigate the effect of temperature on enzyme activity.
• Enzymes are biological catalysts that speed up chemical reactions without being used up themselves.
• The purpose of this practical is to investigate the effect of temperature on enzyme activity.