AQA GCSE BIOLOGY Higher Tier Paper 2H 2020.

GCSE BIOLOGY Higher Tier Paper 2H H 2 *02* IB/M/Jun20/8461/2H Answer all questions in the spaces provided. 0 1 This question is about the decay of milk. 0 1 . 1 Name two types of microorganism that cause decay. [2 marks] 1 2 0 1 . 2 Cows’ milk is pH 6.6. As milk decays, lipids in the milk are broken down. One of the products of the breakdown of lipids causes the pH of milk to decrease. Name the product that causes the pH to decrease. [1 mark] Do not write outside the box 3 *03* Turn over ► IB/M/Jun20/8461/2H Do not write outside the A student investigated the effect of temperature on the time taken for different types of box milk to decay. This is the method used. 1. Put cows’ milk in six test tubes. 2. Keep each test tube at a different temperature. 3. Measure the pH of the milk in each tube every day for 12 days. 4. Record the number of days taken to reach pH 5. 5. Repeat steps 1 to 4 with goats’ milk and with almond milk. 0 1 . 3 Give one way the pH can be measured. [1 mark] 0 1 . 4 Give two control variables the student should have used in this investigation. [2 marks] 1 2 Question 1 continues on the next page