Biology Paper 1

• Photosynthesis


  1. Cut a 10cm piece of pondweed

  2. Place it in a beaker filled with 500cm3 of water

  3. Add sodium hydrogen carbonate to the water

  4. Place the beaker at a set distance from the lamp

  5. Turn on the lamp - allow to start bubbling

  6. Count bubbles produced per minute - record

  7. Repeat at 40cm, 60cm, 80cm, 100cm

  8. Repeat each length 3 times and calculate mean number of bubbles produced
• Microscope


  1. Peel a thin layer of onion skin

  2. Use tweezers to spread onion out on glass slide

  3. Add 2 drops of iodine solution to stain cells

  4. Place glass cover slip - don't trap any air bubbles

  5. Put onto microscope stage and focus using the focus adjuster
• Magnification


  Images Size/Actual Size
• Aseptics

  1. Sterilise petri dish and agar gel using an autoclave

  2. Pour sterile agar plates and allow to set fully

  3. Sterilise inoculating loop by bunsen burner

  4. Dip inoculating loop into microorganism solution and make streaks on surface of agar plate

  5. Replace lid quickly and secure with tape. Store upside down

  6. Incubate at 25C
• Antiseptics


  1. Soak filter paper disks in a variety of solutions

  2. Pour sterile agar plates and allow to set fully

  3. Measure clear area around the disks, also include a control disk
• Osmosis

  1. Prepare a range of sucrose or salt solutions. Range from 0.2 mol dm to 1 mol dm

  2. Set up boiling tubes with these solutions and one with distilled water (control)

  3. Label each with the concentration

  4. Cut 5 identical pieces of potato, use borer to trim same length

  5. Weigh the mass of each

  6. Place potato in solution. Leave for 5 hours

  7. Remove potato and re weigh

  8. Calculate the change in mass
• Osmosis


  The movement of water molecules from a dilute to a concentrated solution through a partially permeable membrane
• Food Tests


  1. Grind up food using pestle and mortar

  2. Mix ground up food with distilled water to dissolve the nutrients

  3. Filter mixture to remove chunks, should be left with a clear liquid in the conical flask

  4. Split liquid between four testubes

  5. Add benedicts to test for sugar and put in water bath - red/orange/green if present

  6. Add iodine for starch - blue/black if present

  7. Add biuret for protein - lilac if present

  8. Add sudan 3 to test for fats - red layer if present
• Amylase Enzyme


  1. Set up spotting tile with few drops of iodine in each well

  2. Add 10cm3 ph buffer to a test tube and add another 10cm of starch solution, keep in water bath

  3. Add 10cm amylase to a second test tube

  4. Pour the amylase into the test tube with the ph buffer and starch solution

  5. Start the stopwatch

  6. Every 10 secs add a drop of solution to spotting tile

  7. Iodine will turn blue if starch is present

  8. When iodine remains orange this means all scratch ahs been digested

  9. Repeat at other ph to find optimum
• Cells can be classified into two main types - prokaryotic (bacteria) and eukaryotic (all other organisms).