3. Trypsin is a protease enzyme used in the manufacture of food for babies - Edexcel - GCSE Biology Combined Science - Question 3 - 2020 - Paper 1

Mashing the food increases its surface area, allowing for more effective action by the enzyme trypsin. This enhanced exposure promotes quicker digestion as the enzyme can access more protein molecules simultaneously.

The temperature should be controlled, as variations in temperature can affect enzyme activity and digestion rates.

The temperature can be controlled by conducting all tests in a temperature-controlled water bath set to a consistent temperature.

As the pH increases from 1 to 4, the time taken to digest the food decreases significantly, indicating that the enzyme is more effective at this pH. However, at pH 5 and 6, the time increases again, suggesting that higher pH levels reduce enzyme efficiency.

To calculate the rate of digestion at pH 1, use the data from pH 4. At pH 4, the trypsin digested 1.5 g at a rate of 0.8 g per minute, which took 1.875 minutes (1.5 g / 0.8 g/min). Since digestion took 42 minutes at pH 1, the rate at pH 1 is:

$ext{Rate} = \frac{1.5 ext{ g}}{42 ext{ min}} = 0.0357 \text{ g/min}$

Rounding this to one significant figure gives approximately 0.04 g per minute.

At pH 1, the trypsin activity is significantly lower due to the highly acidic environment, which hampers enzyme function. In contrast, at pH 4, the enzyme is at or near its optimum pH, facilitating maximum activity and a faster rate of digestion.