6 (a) The activity of the heart can be monitored by measuring the pulse rate. Two students measured their pulse rates before, during and after exercise. The results are shown in Fig. 6.1. 0 20 40 60 80 100 120 140 160 180 0 5 10 15 20 25 time / minutes pulse rate / per minute 30 35 40 45 50 Key: student A student B before exercise during exercise after exercise Fig. 6.1 (i) Describe the changes in the pulse rates shown in Fig. 6.1 for student A and student B. … … … … … … … [4] (ii) Calculate the percentage change in the pulse rate between 0 and 15 minutes for student A. Give your answer to the nearest whole number. Space for working. … % [3] (iii) State two other methods that can be used to monitor the activity of the heart. 1 … 2 … [2] (b) Exercise levels, environmental temperature and changes in water intake can affect the volume and concentration of urine produced. Complete the sentences by circling the correct words in bold. The first sentence has been done for you. More exercise causes the volume of urine to increase / decrease / stay the same and the concentration of urine to increase / decrease / stay the same. A greater intake of water causes the volume of urine to increase / decrease / stay the same and the concentration of urine to increase / decrease / stay the same. A higher environmental temperature causes the volume of urine to increase / decrease / stay the same and the concentration of urine to increase / decrease / stay the same. [2] [Total: 11]

6(a)(i) 1 pulse rates for both students increase, during exercise / at 10–15 minutes / for 5 minutes ; 2 pulse rate for both students plateau, during exercise / at 15–25 minutes / for 10 minutes / until 25 minutes ; 3 pulse rate for both students decreases, after exercise / at 25–40 minutes / for 15 minutes / until 40 minutes ; 4 both students, took the same amount of time to recover from exercise / get back to the same pulse rate as before exercise / AW ; 5 pulse rate for student B increases more than student A / AW ; 6 comparative data quote / manipulation, with units ; 4 6(a)(ii) 94(%) ;;; 3 MP1 correct readings from graph of 64 and 124 MP2 correct calculation, i.e. 93.75(%) ecf wrong graph readings. MP3 correct rounding to whole number ecf MP2 6(a)(iii) any two from: ECG ; listening to the closing of the valves ; AVP ; 2 6(b) (second sentence) ‘increase’ circled and then ‘decrease’ circled ; (third sentence) ‘decrease’ circled and then ‘increase’ circled ; 2 To earn marks, you must describe that both students' pulse rates increase during exercise, plateau during exercise, and decrease after exercise, taking the same time to recover. You also need to state that student B's pulse rate increases more than student A's, and provide comparative data with units. For the calculation, you must correctly read the initial and peak pulse rates from the graph, calculate the percentage change, and round it to a whole number. Finally, you need to state two other ways to monitor heart activity, such as ECG or listening to valve closing, and correctly circle 'increase' then 'decrease' in the second sentence, and 'decrease' then 'increase' in the third sentence.

5 (a) State two factors that affect the volume of urine produced in the human body. 1 … 2 … [2] (b) Nitrogen is an important element for organisms. In a livestock farm, waste from animals contains protein. This waste is often spread on farmland as a fertiliser. Describe how the nitrogen in protein is recycled in the soil into a form that plants can absorb and use. … … … … … … … … … … … [5] (c) Waste from livestock farms often pollutes water courses, such as streams and rivers, leading to a reduction in biodiversity. Explain how the pollution of water courses by animal waste leads to a reduction in biodiversity. … … … … … … … … … … … … … [6] [Total: 13]

4(a) one mark for each row: function name letter on Fig. 4.1 conducts impulses to CNS sensory / afferent, neurone V ; conducts impulses to an effector motor / effector / efferent, neurone Y ; conducts impulses within the CNS relay / connector / intermediate, neurone X ; detects / senses, stimulus / change in temperature receptor U ; contracts / causes movement / carry out response biceps / muscle / effector Z ; 5 A nerve cell / nerve throughout A interneurone A receive A change in, environment / surroundings A heat / hot object A carry out an action ignore triceps 4(b) any four from: 1 vesicles move towards end of, pre-synaptic neurone / axon / AW ; 2 vesicles fuse with (pre-synaptic) membrane ; 3 (named) neurotransmitter released ; 4 neurotransmitter diffuses across, synapse / gap / synaptic cleft ; 5 neurotransmitter binds to receptor, on post-synaptic neurone ; 6 impulse (generated) in post-synaptic neurone ; 7 AVP ; 4 4(c) blinking / pupil reflex / iris reflex / accommodation / corneal reflex / tear reflex / AVP ; 1 5(a) any two from: water / fluid / liquid, intake ; exercise / activity level ; sweating ; temperature ; salt / salty food, intake ; quantity of urea produced / concentration of urea in blood ; (named) drug ; (named) medical condition ; AVP ; e.g. water potential of blood / AW 2 5(b) any five from: 1 protein, broken down / digested / decomposed, to amino acids ; 2 ammonification / mineralisation ; 3 amino acids converted to, ammonium (ions) / NH4+ ; 4 by, decomposers / fungi / bacteria ; if linked to MP1, MP2 or MP3 5 ammonium (ions) / NH4+, converted / oxidised to, nitrate (ions) / NO3– ; 6 nitrification / nitrifying bacteria ; 7 plants, absorb / use, nitrate (ions) (and ammonium ions) ; 8 AVP ; e.g. deamination of amino acids 5 MP5 A nitrite converted to nitrate if ammonium not given

1 (a) Fig. 1.1 shows some of the structures involved in excretion. … … … … … Fig. 1.1 Complete Fig. 1.1 by labelling the structures in the spaces provided. Choose structures from the list: bladder bronchus heart liver lung pancreas trachea ureter urethra [5] (b) Urea is excreted. (i) State the name of the substance that urea is made from. … [1] (ii) State where in the body urea is made. … [1] (c) Urine produced by the kidneys contains three excretory substances: urea, water and mineral salts. Table 1.1 shows the average mass of urea, water and mineral salts in 100 g of blood plasma and in 100 g of urine. Table 1.1 substance average mass / g in 100 g of blood plasma in 100 g of urine water urea mineral salts 90.00 0.03 0.69 95.00 2.00 1.35 Calculate the percentage increase in the average mass of mineral salts between blood plasma and urine. Give your answer to two decimal places. Space for working. … % [3] (d) Describe the process that produces the carbon dioxide that is excreted by the lungs. … … … … [2] (e) State the name of the component of blood that transports carbon dioxide to the lungs. … [1] [Total: 13]

1(a) bronchus ; lung ; liver ; ureter ; bladder ; 5 1(b)(i) amino acids ; 1 1(b)(ii) liver ; 1 1(c) 95.65(%) ;;; 3 1(d) any two from: respiration ; aerobic / use of oxygen ; to break-down of glucose / nutrient molecules ; correct word equation ; 2 1(e) plasma ; 1 (a) To earn marks, you must correctly identify and label each of the five specified structures on the diagram. (b)(i) You need to state 'amino acids' as the substance urea is made from. (b)(ii) You must state 'liver' as the location where urea is made. (c) You need to correctly calculate the percentage increase and provide the answer to two decimal places. (d) You must provide two correct points describing the process that produces carbon dioxide, such as respiration, aerobic process, breakdown of glucose, or a correct word equation. (e) You must state 'plasma' as the component of blood that transports urea.

6 (a) (i) The box on the left shows the beginning of a sentence. The boxes on the right show some sentence endings. Draw two straight lines from ‘Excretion’ to the boxes on the right to make two correct sentences. Excretion is the removal of excess substances from an organism. is the removal of toxic materials from an organism. is the taking in of materials for energy and growth. is the movement of digested food molecules into cells. is the passing out of undigested food from an organism. [2] (ii) The kidney filters the blood and produces a liquid called urine. State three substances that are found in the urine of a healthy person. 1 … 2 … 3 … [3] (b) Fig. 6.1 is a diagram of part of the human excretory system and associated blood vessels. P R Q Key: direction of blood flow Fig. 6.1 State the names of parts P, Q and R in Fig. 6.1. P … Q … R … [3] (c) The volume and concentration of urine produced is affected by changes in water consumption, temperature and exercise levels. Table 6.1 shows three different conditions. Complete Table 6.1 by writing increases or decreases in the boxes to show the effect of each condition on the volume and concentration of urine produced. Table 6.1 condition volume of urine concentration of urine increase in water consumption increase in temperature increase in exercise level [3] (d) Protein can be broken down into amino acids. (i) List four chemical elements that are always found in protein. 1 … 2 … 3 … 4 … [2] (ii) State the name of the organ in the human body that breaks down excess amino acids. … [1] (e) Fig. 6.2 shows some chemical reactions that are catalysed by enzymes. The enzyme catalysing the reaction is shown on the arrow. Complete Fig. 6.2 by filling in the names of the four missing molecules. amylase starch … … protein amino acids lipase fats … and … Fig. 6.2 [3] [Total: 17]

6(a)(i) is the movement of digested food molecules into cells. is the passing out of undigested food from an organism. is the removal of excess substances from an organism. Excretion is the removal of toxic materials from an organism. is the taking in of materials for energy and growth. ;; 2 one mark per line R each additional line 6(a)(ii) any three from: water ; urea ; salts / (named) ions ; hormones ; AVP ; 3 6(b) P – renal artery ; Q – bladder ; R – ureter ; 3 6(c) condition volume of urine concentration of urine increase in water uptake increases decreases increase in temperature decreases increases increase in exercise level decreases increases ;;; 3 one mark per correct row 6(d)(i) carbon, hydrogen, oxygen ; nitrogen ; 2 6(d)(ii) liver ; 1 6(e) (simple) sugars ; (named) protease ; fatty acids and glycerol ; 3 A glucose / maltose

Cambridge IGCSE Biology · 0610

IGCSE Biology (0610) Excretion in humans past paper questions

Questions on the kidney, urine formation, and osmoregulation.

92 free questions from 2017–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Excretion in humans in IGCSE Biology 0610 exams, 2020–2025

Across 2020–2025, Excretion in humans accounted for 114 questions worth 388 marks in Cambridge IGCSE Biology (0610) papers.

By year
Year	Questions	Marks
2020	16	65
2021	20	42
2022	19	62
2023	21	64
2024	18	74
2025	20	81

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13.1 Excretion in humans297 marks

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Paper 2 · 46 qs
Paper 3 · 14 qs
Paper 4 · 9 qs

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2021 May/Jun · Paper 3 · Q6 · 11 marks
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2021 Oct/Nov · Paper 4 · Q5 · 13 marks
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2020 May/Jun · Paper 3 · Q1 · 13 marks
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2020 Oct/Nov · Paper 3 · Q6 · 17 marks
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2021 May/Jun · Paper 1 · Q19 · 1 mark
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Mark scheme — 2021 Paper 1 Q19
Answer: C
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