Biology 0610/63 May/June 2023: question paper and mark scheme

Question

A student investigated the nutrient content of three types of drink: • drink A • drink B • drink C. The student used these methods for the three tests on each of the drinks: Test 1 Testing for reducing sugars: • Label three test-tubes A, B and C. • Put 1 cm3 of drink A into test-tube A. • Put 1 cm3 of drink B into test-tube B. • Put 1 cm3 of drink C into test-tube C. • Add 1 cm3 of Benedict’s reagent to each test-tube. • Put all three test-tubes into a hot water-bath. • Start the stop-clock and leave the test-tubes in the water-bath for five minutes. • After five minutes, remove the test-tubes from the water-bath. • Observe and record the colours in each test-tube. Test 2 Testing for starch: • Place two drops of each drink onto a white tile. • Add two drops of iodine solution to each drink sample. • Observe and record the colours on the tile for each sample. Test 3 Testing for protein: • Label three test-tubes A, B and C. • Put 1 cm3 of drink A into test-tube A. • Put 1 cm3 of drink B into test-tube B. • Put 1 cm3 of drink C into test-tube C. • Add 1 cm3 of biuret reagent to each drink sample. • Observe and record the colours in each test-tube. (a) The student’s observations are shown in Fig. 1.1. Test 1 drinks A and B were blue, C was brick-red Test 2 drinks B and C were both brown, and A was blue-black Test 3 drinks B and C were both lilac, while A was blue Fig. 1.1 (i) Prepare a table to record the colours observed by the student for all three tests for each drink. Do not include conclusions in your table. [4] (ii) State which nutrients are present in each drink. drink A …… drink B …… drink C …… [3] (iii) Identify one safety hazard associated with Test 1. …… [1] (b) The vitamin C content and the fat content of three other drinks D, E and F were determined. It was found that: • drink D contained vitamin C • drink E contained fat • drink F contained vitamin C and fat. (i) State the reagent used when testing for vitamin C. …… [1] (ii) Describe the method for the emulsion test for fats. …… [2] (iii) The results for one of the drinks are shown in Table 1.1. Table 1.1 test observation vitamin C the solution is colourless fat a white emulsion has formed Identify the drink from the results provided in Table 1.1. drink …… [1] (iv) Explain how you identified the drink from the results provided in Table 1.1. …… [1] (c) Three types of food contain different concentrations of the enzyme catalase. Catalase catalyses the breakdown of hydrogen peroxide to release water and oxygen gas: hydrogen peroxide water + oxygen The production of oxygen gas can be used to measure the activity of the enzyme. Plan an investigation to compare the concentrations of catalase in the three types of food. …… [6] [Total: 19]

Question

(a) The nutrient content of foods can affect a person’s bones. In a study, the diet and bone density of 120 women were monitored for two years. The women were all between 50 and 70 years of age. The scientists: • calculated the mean daily calcium intake for each woman • measured the change in density of one of their bones by using X-ray scans. The results for five of the women are shown in Table 2.1. Table 2.1 mean daily calcium intake mean change in bone for each woman density / mg per day / mg per cm2 per year 250 –8.6 750 –5.4 1250 –1.2 1750 +1.2 2250 +4.2 (i) Plot a line graph on the grid of the data in Table 2.1. One axis has been started for you. 0.0 [4] (ii) State two conclusions for the data in your graph. 1 …… 2 …… [2] (iii) Identify the independent variable in this investigation. …… [1] (iv) Describe two variables that the scientists should have considered when selecting women for the study. 1 …… 2 …… [2] (v) Suggest a reason for a large number of women (120) being included in the study. …… [1] (vi) State one way this study is not representative of the population. …… [1] (vii) A student stated that more women were losing bone mass than were gaining bone mass. Explain why this statement may not be correct for the data in this study. …… [1] (b) Fig. 2.1 is a photograph of a femur, which is a bone in the leg. P Q magnification ×0.3 Fig. 2.1 (i) Make a large drawing of the bone shown in Fig. 2.1. [4] (ii) The length of line PQ represents the length of the femur in Fig. 2.1. Measure the length of line PQ on Fig. 2.1. length of line PQ on Fig. 2.1 …… mm Use your measurement and the formula to calculate the actual length of the bone. length of line PQ on Fig. 2.1 magnification = actual length of the bone Give your answer to three significant figures. Space for working. …… mm [3] (iii) Fig. 2.2 shows a bone from a person who had vitamin D deficiency. magnification ×0.3 Fig. 2.2 State two ways the bone in Fig. 2.2 is different from the bone in Fig. 2.1. 1 …… 2 …… [2] [Total: 21]