Biology 0610/32 February/March 2025: question paper and mark scheme

Question

(a) Complete the sentences to describe enzymes. Use words or phrases from the list. Each word or phrase may be used once, more than once or not at all. amino acids calcium carbon fatty acids hydrogen iron magnesium molecules nitrogen oxygen water Enzymes are proteins. All proteins are made up from a chain of smaller …… called …… . All proteins contain the chemical elements …… , …… , …… and …… . [4] (b) Enzymes function as biological catalysts. Describe what is meant by the term catalyst. …… [2] (c) Fig. 1.1 shows a reaction catalysed by an enzyme. substrate enzyme Fig. 1.1 Use Fig. 1.1 to describe enzyme action. …… [3] (d) Some bacteria are found living in very high temperatures. Fig. 1.2 shows the effect of temperature on the activity of an enzyme in these bacteria. 12 10 8 enzyme activity / arbitrary units 6 4 2 0 0 10 20 30 40 50 60 70 temperature / °C Fig. 1.2 Using the information in Fig.1.2: (i) Identify the optimum temperature for this enzyme. …… °C [1] (ii) Identify the temperature when the enzyme is completely denatured. Explain how you identified your choice. temperature …… °C explanation …… [2] (iii) Calculate the difference in enzyme activity between 20 °C and 40 °C. Space for working. …… arbitrary units [2] (iv) The mean body temperature for humans is 37 °C. On Fig. 1.2, sketch the curve for the activity of an enzyme found in humans. [2] [Total: 16]

Question

(a) Fig. 2.1 shows the human digestive system. A B C D E F G H J K Fig. 2.1 (i) The human digestive system is made up of the alimentary canal and the associated organs. Food moves through the alimentary canal, but does not move through the associated organs. The pancreas is one of the associated organs. State the letter in Fig. 2.1 that identifies the pancreas and state the name of two enzymes secreted by the pancreas. letter …… enzyme 1 …… enzyme 2 …… [3] (ii) State one letter in Fig. 2.1 that identifies one other associated organ of the digestive system. Name this organ. letter …… name …… [1] (iii) In Fig. 2.1, structure J is the small intestine. State two functions of the small intestine. 1 …… 2 …… [2] (b) Some antibiotics are taken into the body as tablets. Fig. 2.2 shows the concentration of antibiotic in the blood after a tablet is taken. 2.0 1.5 concentration of antibiotic in blood 1.0 / arbitrary units 0.5 0 0 2 4 6 8 10 time after antibiotic is taken / hours Fig. 2.2 (i) Using Fig. 2.2, describe how the concentration of antibiotic in the blood changes. …… [3] (ii) Circle the name of the process of taking substances into the body. assimilation digestion egestion excretion ingestion [1] (iii) Antibiotics are transported around the body by the blood. State the name of the component of blood that transports substances such as nutrients, hormones and antibiotics. …… [1] (iv) State the type of organism killed by antibiotics. …… [1] [Total: 12]

Question

(a) Fig. 3.1 shows blood flow through a human heart. The arrows show the direction of blood flow. A B C septum Fig. 3.1 (i) On Fig. 3.1, draw a label line and the letter X to identify the muscular wall of the left ventricle. [1] (ii) Describe the path taken by blood as it moves from A to B in Fig. 3.1. …… [3] (iii) State the name of blood vessel C shown in Fig. 3.1. …… [1] (b) The activity of the heart can be monitored using an ECG. Fig. 3.2 shows the results of an ECG for a person who has been resting for 15 minutes. one heart beat Fig. 3.2 Fig. 3.3 shows the results of ECGs for the same person: • resting • during vigorous physical activity • one minute after physical activity • one hour after physical activity. (i) Draw lines to link each activity with its ECG. Draw three lines. One has been done for you. activity ECG resting during vigorous physical activity one minute after physical activity one hour after physical activity Fig. 3.3 [2] (ii) State two other ways that the activity of the heart can be monitored. 1 …… 2 …… [2] (c) During vigorous physical activity humans respire anaerobically. (i) Tick (✓) three statements that describe anaerobic respiration in humans. alcohol is produced carbon dioxide is produced glucose is required lactic acid is produced oxygen is required releases less energy per substrate molecule than aerobic respiration [3] (ii) State how vigorous exercise affects the rate and depth of breathing. rate …… depth …… [1] [Total: 13]

Question

Fig. 4.1 shows part of a leaf from a Mexican hat plant. offspring Fig. 4.1 (a) The Mexican hat plant shown in Fig. 4.1 is reproducing. Tick (✓) three statements that describe the reproduction shown in Fig. 4.1. Gametes are produced. Involves implantation. Only one parent is involved. Pollination occurs before the stage shown in Fig. 4.1. The offspring are genetically identical to each other. The reproduction is asexual. [3] (b) Fig. 4.2 shows a section of a flower. L M N Fig. 4.2 Identify structures L, M and N shown in Fig. 4.2. L …… M …… N …… [3] (c) Fig. 4.3 shows a flower from a Crocus plant. petals Fig. 4.3 (i) Using the information in Fig. 4.3, predict the type of pollination used by the Crocus plant. Explain your prediction. prediction …… explanation …… [3] (ii) Describe the process of pollination. …… [2] (d) Fig. 4.4 is a photomicrograph of pollen grains. P Q W R V S 0.03 mm T Fig. 4.4 (i) State one letter in Fig. 4.4 that identifies a pollen grain from a wind-pollinated flower. …… [1] (ii) Using the information in Fig. 4.4, estimate the maximum length of pollen grain V. Include the unit. …… unit …… [2] (iii) State two characteristics of pollen grains from insect-pollinated flowers. 1 …… 2 …… [2] [Total: 16]

Question

(a) Fig. 5.1 shows a leaf insect on a leaf. Fig. 5.1 (i) State one feature visible in Fig. 5.1 that identifies this leaf insect as an insect. …… [1] (ii) State one feature visible in Fig. 5.1 that identifies this leaf insect as an arthropod. …… [1] (b) The leaf insect in Fig. 5.1 has adaptive features. (i) Describe the adaptive features visible in the insect shown in Fig. 5.1, and explain the importance of these features. …… [3] (ii) Complete the sentences by writing a suitable word in each space. In a population of leaf insects there are differences between the individuals. The term for the difference between individuals of the same species is …… . Individuals that reproduce are able to pass on their …… to the next generation. Over many generations the features of individuals that reproduce will be more common in the population. This process is called …… selection. [3] (c) Some species of leaf insect are endangered. State three ways that endangered species can be conserved. 1 …… 2 …… 3 …… [3] [Total: 11]

Question

(a) Barley is a crop plant. Fig. 6.1 shows the yield of barley per unit area of crops grown between 1945 and 2020. 8 C 6 yield of barley / tonnes per 4 B unit area 2 A 0 1940 1960 1980 2000 2020 year Fig. 6.1 (i) Selective breeding of barley plants has increased the yield of barley. Identify the period, A, B or C, when the largest increase in yield occurred. Explain how you made your choice. period …… explanation …… [2] (ii) Using the information in Fig. 6.1, calculate the yield of barley in the year 2000 in kilograms per unit area. One tonne = 1000 kg. Space for working. …… kg [2] (iii) The list contains statements that describe selective breeding of barley plants to increase yield. A Humans select barley plants with a high yield. B New barley plants are grown. C Offspring with a high yield are selected and bred together. D Pollination and fertilisation occurs. E Seeds form. F The process is repeated over many generations. Arrange the statements in the correct order to describe the process of selective breeding in barley plants. Two have been done for you. A B [2] (iv) State three other ways that humans can increase the yield of barley. 1 …… 2 …… 3 …… [3] (b) Barley can be grown as a monoculture. (i) Describe what is meant by the term monoculture. …… [1] (ii) State one advantage and one disadvantage of growing crops as monocultures. advantage …… disadvantage …… [2] [Total: 12]