Biology 0610/63 October/November 2021: question paper and mark scheme

Question

Catalase is an enzyme found in many plants. It speeds up the break down of hydrogen peroxide into water and oxygen, as shown in Fig. 1.1. hydrogen peroxide water + oxygen Fig. 1.1 The oxygen produced during the reaction forms a foam on the surface of the liquid. The height of the foam can be used as an indication of the activity of catalase. (a) A student investigated the activity of catalase in three different types of plant tissue: seeds, roots and fruits. The student used this method: Step 1 Put one seed into a test‑tube labelled S1. Step 2 Cut a small piece of root and place it into a test‑tube labelled R1. Step 3 Cut a small piece of fruit and place it into a test‑tube labelled F1. Step 4 Put 5 cm3 of 6% hydrogen peroxide solution into each test‑tube. Leave for three minutes. Step 5 After three minutes, use a ruler to measure the height of the foam produced in each test‑tube. The student’s results from step 5 are shown in Fig. 1.2. results S1 = 40 mm of foam R1 = 14 mm of foam F1 = 4 mm of foam Fig. 1.2 Step 6 Repeat step 1 to step 5 with fresh plant tissues and fresh hydrogen peroxide solution to get a second set of results. Fig. 1.3 shows the second set of test‑tubes from step 6 after three minutes. S2 R2 F2 foam height of foam seed root fruit Fig. 1.3 (i) Prepare a table to record the two sets of results and the average height of the foam for each tissue. Measure the heights of the foams in the three test‑tubes in Fig. 1.3. Calculate the average height of the foam for each tissue. Include in your table: • the student’s results from Fig. 1.2 • the heights of the foams you have measured from Fig. 1.3 • the average heights you have calculated. [5] (ii) State a conclusion for these results. …… [1] (iii) Identify one potential source of error in this investigation. …… [1] (iv) The student collected two sets of results for each plant tissue. Explain why it would have been better to have collected three sets of results. …… [1] (v) State two variables that should have been kept constant during this investigation. 1 …… 2 …… [2] (vi) State the variable that was measured (the dependent variable) in this investigation. …… [1] (vii) Identify one safety risk when carrying out this investigation and describe how the risk could be reduced. risk …… method of reducing risk …… [2] (b) A student wanted to calculate the rate of gas production but could not do this using the height of the foam. Describe how the student could change the method to collect the data they needed and state how they would calculate the rate of gas production. change to method …… how the rate would be calculated …… [2] (c) (i) The student added iodine solution to samples of the three types of plant tissue. The student observed the colour of the iodine solution on the plant tissue after a few minutes. Their observations are shown in the table. Complete the table by writing a conclusion for each observation. plant tissue observation conclusion seed blue‑black root blue‑black fruit yellow‑brown [2] (ii) State the name of the reagent that would be used to test a seed for protein. …… [1] (d) A student stated that: ‘Different types of plant tissue will lose different amounts of water by osmosis when immersed in a salt solution.’ Plan an investigation to find out if the student was correct. …… [6] [Total: 24]

Question

Fig. 2.1 is a photograph of the cut surface of an apple. Fig. 2.1 (a) Make a large drawing of the cut surface of the apple shown in Fig. 2.1. [4] (b) Fig. 2.2 is a photograph of an apple ermine moth (Yponomeuta malinellus). B A magnification ×9 Fig. 2.2 (i) Line AB represents the length of the apple ermine moth. Measure the length of line AB on Fig. 2.2. length of line AB on Fig. 2.2 …… mm Use your measurement and the formula to calculate the actual length of the apple ermine moth. length of line AB on Fig. 2.2 magnification = actual length of the apple ermine moth Give your answer to two significant figures. Space for working. …… mm [3] (ii) Fig. 2.3 is a photograph of a bird‑cherry ermine moth (Yponomeuta evonymella). magnification ×9 Fig. 2.3 Identify two similarities and one difference between the apple ermine moth in Fig. 2.2 and the bird‑cherry ermine moth in Fig. 2.3. similarity 1 …… similarity 2 …… difference …… [3] (c) In a study, the number of apple ermine moths in one area was recorded every two weeks over a 12‑week period. The results are shown in Table 2.1. Table 2.1 number of apple ermine week moths 0 0 2 0 4 11 6 22 8 22 10 18 12 4 (i) Plot a line graph on the grid of the data in Table 2.1. [4] (ii) Use your graph to estimate the number of moths in week 11. Show on your graph where you took your readings. [2] [Total: 16]