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• What is Casein?


  Protein in milk
• What is Trypsin?


  Enzyme that digests Casein
• What is the independent variable?

  Temperature
• What is the dependent variable?


  Reaction rate
• How many temperatures do you investigate?

  20, 30, 40, 50 & 60.C
• What are the control variables?

  pH, enzyme concentration & substrate concentration
• What happens when Trypsin is added to dilute milk powder solution?

  Goes clear.
• 1st step:


  Write 'X' on side of 3 test tubes
• 2nd step:


  Add 10cm3 milk powder solution to each tube
• 3rd step:


  Add 2cm3 trypsin solution to 2cm3 pH 7 buffer in another 3 test tubes
• 4th step:


  put all tubes in water bath at 20.C for 10 mins
• 5th step:


  mix tubes, add cork, invert 5 times & place back in water bath
• 6th step:


  time how long it takes for milk to turn clear (can see 'X') using stopclock
• 7th step:


  repeat at 30, 40, 50 & 60.C.
• 8th step:


  draw graph- reaction rate against temperature