Required Practicals

• Investigate the effect of a range of concentrations of salt or sugar solutions on the mass of plant tissue

  1. Cut some cylinders of potato tissue and measure mass

  2. Place the cylinders in different concentrations of sugar solutions

  3. After around 30 mins, remove the cylinders + remeasure mass
• Test for sugars

  1. Add Benedicts solution

  2. Heat in a water bath for 2 mins

  3. If present, solution turns red
• Test for Starch

  1. Add iodine solution

  2. If present, solution turns blue-black
• Test for protein

  1. Add Biuret reagent

  2. If present, reagent turns purple
• Use a light microscope to observe, draw and label a selection of plant and animal cells

  1. Place tissue sample on microscope slide

  2. Add a few drops of a suitable stain

  3. Lower a coverslip onto the tissue

  4. Place the slide on the microscope stage and focus on the cells using low power

  5. Change to high power and refocus

  6. Draw any types of cells that can be seen

  7. Add scale line to diagram
• Investigating the effect of light intensity on the rate of photosynthesis using an aquatic organism such as pondweed

  1. Place pondweed in beaker

  2. Shine light using a lamp at a specific distance away

  3. Record number of gas bubbles coming from pondweed in one min

  4. Repeat with lamp at different distances
• Investigate the effect of pH on the rate of reaction of amylase enzyme

  1. Put test tube with Starch solution + test tube with amylase into water bath at 37°C

  2. After 5 mins add amylase to starch

  3. Every 30 secs take a drop from mixture and test for starch with iodine solution

  4. Record how long it takes for the starch to be completely digested

  5. Repeat at different pH values using different buffer solutions
• Investigating the effect of a factor on human reaction time

  1. Experimenter holds in ruler vertically from the end

  2. The subject has their finger + thumb a small distance apart, either side of ruler, on 50cm line

  3. Experimenter lets go of ruler, subject catches it

  4. Distance ruler travels is noted

  5. Experiment is repeated on subjects that have just drunk coffee or soda + subjects that haven't
• Measure the population size of a common species in a habitat

  1. Place a quadrat on ground at random

  2. Count number of individual plants of 1 species in the quadrat

  3. Repeat process

  4. Find mean number of plants

  5. Work out mean in 1m²

  6. Measure area of whole habitat

  7. Multiply the number of plants in 1m² by whole area