CP1-Reaction Rate

Question 1

Objectives of Core Practical 1-Investigate a factor affecting the initial rate of reaction

Answer 1

Objectives:

• understand initial rate of enzyme activity
• understand why measuring the initial rate is important

Question 2

Risks?

Answer 2

• trypsin above 1% is irritant, may cause allergic reaction
• water bath/Bunsen burner can cause fires
• glassware can break and cause cuts on skin
• wear gloves and goggles
• wash splashes from the skin as soon as possible
• avoid dropping glass equipment

Question 3

Method?

Answer 3

• serially dilute concentrations of 1%trypsin (10^-1, 10^-2, 10^-3), using 1:9 ratio of trypsin to distilled water ratio and a syringe NOT a measuring cylinder
• make up 10 cm^3 of each concentration
• 2cm^3 1% trypsin and distilled water into a cuvette, use as a reference and set the colorimeter absorbance to 0
• 2cm^3 of milk suspension into a cuvette and add 2cm^3 of trypsin solution and place in colorimeter quickly and start the stopwatch
• record the absorbance at 10 second intervals for 2 minutes
• rinse the cuvette and repeat with the same concentration twice more
• record results in a table and calculate mean absorbances
• repeat with different concentrations of trypsin solution

Question 4

Variables?

Answer 4

IV- trypsin concentration/enzyme concentration (changes)
DV- rate of reaction in absorbance units (s^-1)
CV- volume of milk suspension/volume of substrate, pH, temperature