Biology Experiment Essay

1441 Words6 Pages
Identify data sources, plan, choose equipment or resources and perform a first-hand investigation to test the effect of increased temperature, change in pH and change in substrate concentrations on the activity of named enzyme(s). Part A effect of temperature Information Rennin is an enzyme that acts on the milk protein casein, causing it to set (clot and form a curd). This has the effect of keeping liquid foods in the stomach for long enough so that some digestion can take place. Rennin is found in the stomachs of babies and young children whose diet is mainly milk. Another source of rennin is junket tablets, which are used in setting milk into a solid junket or dessert. Junket tablets are used as a source of rennin in this experiment. Materials (per group) (This experiment may be done in groups of four. Each student can look after two temperature set-ups.) » 2 Bunsen burners
 »2 tripods » 2 wire gauzes » 2 × 150 mL beakers » 2 × 250 mL beakers for 70°C and 80°C water baths
 » 5 Styrofoam cups for unheated water baths
 » 8 thermometers 0–100°C
» 16 test tubes in a rack
 » 10 mL measuring cylinder
» junket tablet
» 50 mL milk » Crushed ice
» dropper
» plastic spoon
» marking pen
 » Distilled water
Note: Thermostatically controlled water baths may be used if available. Method 1 Prepare half-filled water baths by mixing different amounts of tap water, boiling water and ice in the styrofoam beakers to give one of each temperature: 10°C, 20°C, 30°C, 40°C and 50°C. Maintain the 70°C and 80°C temperatures by placing water in the beakers on the Bunsen burners and adjusting with cold water as necessary. Alternatively, use thermostatically controlled water baths for the 30°C, 40°C, 50°C, 60°C, 70°C and 80°C experiments. Place thermometers in each water bath to record the actual temperature in each bath. 2 Using the 10 mL measuring cylinder, add 3
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