Biology 0610/42 February/March 2024: question paper and mark scheme

Question

Enzymes are catalysts. (a) (i) Describe what is meant by the term catalyst. …… [2] (ii) Enzymes are proteins. State the names of the chemical elements found in all proteins. …… [2] (b) Lipase is an enzyme found in the human digestive system. Fig. 1.1 shows the effect of pH on the percentage activity of lipase. 100 80 60 percentage activity 40 20 0 3 4 5 6 7 8 9 10 11 pH Fig. 1.1 Describe and explain the change in percentage activity of lipase shown on Fig. 1.1. …… [6] (c) (i) Complete the word equation to show the substrate and products for lipase. lipase + [2] (ii) Lipase acts in the duodenum. Explain how the body provides a suitable pH for lipase activity. …… [3] [Total: 15]

Question

Fig. 2.1 shows a cross-section of a human heart. C B A Fig. 2.1 (a) (i) On Fig. 2.1, label with an R the position of the right ventricle. [1] (ii) State the names of the structures labelled A and B on Fig. 2.1. A …… B …… [2] (iii) Complete the sentence about blood vessel C. Blood vessel C transports blood from the …… to the …… . [2] (b) Fig. 2.2 shows a cross-section of part of a heart that has an incomplete structure. atria incomplete heart structure Fig. 2.2 Explain how the incomplete heart structure shown in Fig. 2.2 may affect a person’s ability to transport oxygen. …… [3] (c) Fig. 2.3 shows how the body uses aerobic and anaerobic respiration during the first 120 seconds of vigorous physical activity. Between 0 and 20 seconds, the body also uses stored energy. 100 80 aerobic respiration 60 percentage of energy released 40 20 anaerobic respiration 0 0 20 40 60 80 100 120 time / s Fig. 2.3 (i) Describe the data shown in Fig. 2.3. …… [4] (ii) State the balanced chemical equation for aerobic respiration. …… [2] (iii) During anaerobic respiration an oxygen debt can build up. State the name of the chemical that causes this oxygen debt. …… [1] [Total: 15]

Question

(a) Fig. 3.1 shows a growing plant. The plant is growing in the dark. plant shoot soil plant root Fig. 3.1 (i) State the name of the growth response shown by the plant shoot in Fig. 3.1. …… [1] (ii) Explain how the growth of the plant shoot in Fig. 3.1 is controlled. …… [3] (b) Plant roots growing towards water is another growth response. State two uses of water in a plant. 1 …… 2 …… [2] (c) A student measured the root length of a bean seedling over a period of 120 hours. Fig. 3.2 shows the results. 30 20 root length / mm 10 0 0 24 48 72 96 120 time / hours Fig. 3.2 Calculate the percentage increase in root length between 48 hours and 96 hours. Give your answer to two decimal places. Space for working. …… % [3] [Total: 9]

Question

Fig. 4.1 shows the concentrations of female sex hormones during the menstrual cycle. S progesterone R concentration of hormones FSH 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 day of menstrual cycle Fig. 4.1 (a) Identify, from Fig. 4.1, hormone: R …… S. …… [2] (b) State the day or days of the menstrual cycle shown in Fig. 4.1 when: ovulation is most likely to occur …… shedding of the uterine lining occurs. …… [2] (c) Describe how the concentration of progesterone would change during pregnancy. Give a reason for this change. …… [2] (d) State the sites of production of progesterone during a menstrual cycle and during pregnancy. during a menstrual cycle …… during pregnancy …… [2] (e) Describe the role of FSH in the menstrual cycle. …… [1] [Total: 9]

Question

Fig. 5.1 shows part of a monkey flower plant. Fig. 5.1 (a) (i) State two pieces of evidence, visible in Fig. 5.1, that show that monkey flower plants are pollinated by insects. 1 …… 2 …… [2] (ii) The monkey flower plant in Fig. 5.1 reproduces sexually. Describe the advantages and disadvantages of sexual reproduction for monkey flower plants. …… [4] (b) Monkey flower plants were introduced to Europe from North America about 200 years ago. Scientists measured the leaf area of five monkey flower plants growing in Europe and five monkey flower plants growing in North America. Their results are shown in Table 5.1 and Table 5.2. Table 5.1 plants growing in Europe plant leaf area / cm2 number 1 310 2 335 3 390 4 348 5 365 mean 350 Table 5.2 plants growing in North America plant leaf area / cm2 number 1 285 2 310 3 302 4 315 5 294 mean (i) Using the data in Table 5.2, calculate the mean leaf area for plants growing in North America. Give your answer as a whole number and include the unit. [2] (ii) State a conclusion for the results shown in Table 5.1 and Table 5.2. …… [1] (iii) Ancestors of monkey flower plants had a much smaller leaf area. Explain how the monkey flower plants have developed a larger leaf area over time. …… [5] [Total: 14]

Question

(a) Fig. 6.1 shows part of the carbon cycle in the ocean. Sun carbon dioxide in the atmosphere ocean surface phytoplankton feeding krill krill faeces zooplankton eating krill faeces Fig. 6.1 (not to scale) (i) Phytoplankton contain chlorophyll. Explain how phytoplankton lower carbon dioxide concentrations in the atmosphere. …… [2] (ii) Suggest the role of zooplankton in this ecosystem. …… [1] (iii) State the names of two processes that add carbon dioxide to the atmosphere. 1 …… 2 …… [2] (iv) Describe the effect on the environment of additional carbon dioxide in the atmosphere. …… [3] (b) Fig. 6.2 shows the pyramid of energy for a food chain in an ocean ecosystem. Fig. 6.2 (i) On Fig. 6.2, label the trophic level containing herbivores. [1] (ii) Explain why pyramids of energy usually have fewer than five trophic levels. …… [3] (iii) State two advantages of using a pyramid of energy rather than a pyramid of biomass to represent a food chain. 1 …… 2 …… [2] (c) The oceans contain fish stocks that can be managed as a sustainable resource to provide food for humans. (i) State what is meant by the term sustainable resource. …… [2] (ii) Fishing can be managed to promote the conservation of fish stocks. Explain one way that fishing can be managed to conserve fish stocks. …… [2] [Total: 18]