Required Practicals

• Optical Microscopes

  -Place prepared slide onto stage, use clips to hold place

  -Use lowest objective lens (4x)

  -Turn course focussing dial

  -Look into eyepiece, and slowly turn course dial until cells turn into focus

  -Magnification of eyepiece x Magnification of objective lens

  -Measure in mm the slide and draw ruler line on scale bar
• Bacterial growth 


  -Sterilise loop, dish, agar jelly

  -Use loop to spread bacteria over jelly

  -Place sterile filter paper discs with antibiotics on plate

  -Incubate plate upside down at 25°C

  -Area of zone of inhibition= pi x radius2
• How osmosis effects plant cells

  % CHANGE= change in value/original value X100


  -First peel a potato

  -Use cork borer to make 3 cylinders of potato

  -Use a scalpel to trim them to 3cm

  -Measure length of each cylinder using ruler

  -Measure mass of each cylinder using a balance

  -Place each cylinder into test tube

  -Add 10cm3 of a 0.5 molar sugar solution into FIRST tube

  -Add 10cm3 of a 0.25 molar sugar solution into SECOND

  -Add 10cm3 of distilled water to THIRD

  -Leave overnight

  -Remove potato cylinders and dry on paper towel

  -Finally re measure length and mass of cylinders
• Effect of PH on amylase

  Place one drop of iodine solution into each dip of a spotting tile

  First test tube add 2cm3 of starch solution

  Second test tube add 2cm3 of amylase solution

  Third test tube add 2cm3 of PH 5 buffer solution

  Place all tubes in 30°c water bath for 10 minutes

  Combine all 3 into one and mix with rod

  Place back in water bath and start 30s timer

  Use rod to place a drop of solution into dip with iodine

  Iodine turns blue/black and continue to place drops until iodine remains orange

  REPEAT experiment using PH buffers 6,7,8
• Food tests


  1. Take food samples and grind with distilled water

  2. Transfer paste into beaker with more distilled water

  3. STIR and FILTER
• CARBOHYDRATES


  • 2cm3 of food solution into test tube
  • Add iodine (orange) if present turns (blue or black)
• SUGARS


  • 2cm3 of food solution into test tube
  • Add 10 drops of Benedict's solution (blue)
  • Place test tube into half filled beaker with hot water
  • If present Benedict's solution turns green/yellow/red
• PROTEIN


  • 2cm3 of food solution into test tube
  • Add 2cm3 of biuret solution (blue) if present turns (purple)
• LIPIDS/FATS


  • 2cm3 of food solution to test tube
  • Add ethanol and shake solution
  • If present, turns (cloudy, colourless)
• Photosynthesis required practical

  • Place boiling tube 10cm away from an LED light
  • Fill boiling tube with sodium hydrogen carbonate solution
  • Place pondweed into tube, with the cut end at the top
  • Leave for 5 minutes
  • Count how many bubbles are produced in 1 minute
  • Repeat 2 more times
  • Calculate the mean
  • Repeat experiment 20,30,40cm away
• Inverse square law (photosynthesis)

  • Double the distance, light intensity falls by 4x
  • Causes bubbles to fall by 4x