1 (a) Nutrition is one of the characteristics of living organisms. Identify the characteristics of living organisms defined as the chemical reactions in cells that break down nutrient molecules and release energy … the ability to detect and respond to changes in the environment. … [2] (b) Fig. 1.1 shows part of the alimentary canal and associated organs. Fig. 1.1 (i) Draw the letter X on Fig. 1.1 to identify the position of the liver. [1] (ii) The arrow shows the direction the food moves as it passes into the small intestine. Complete these sentences about what happens in the small intestine. Large insoluble molecules are broken down by the process of … . Small food molecules are then moved into the blood by the process of … . [2] (c) A student investigates nutrition in plants. Sugar is stored as starch in a leaf. The student puts black paper around a green leaf still attached to the plant. After two days she takes the leaf from the plant and removes the black paper. She then tests the leaf for starch using iodine solution. Fig. 1.2 shows the results. iodine solution turns blue-black iodine solution stays orange-brown starch test clip to hold paper leaf attached to plant black paper strip Fig. 1.2 Explain the results seen in Fig. 1.2 for the area that was covered by black paper. … … … [2] (d) Different plant tissues in the stem have different functions. Name the tissue that transports sugars in the stem. … [1] (e) Starch and sugar are carbohydrates. Table 1.1 shows the mass of carbohydrates in some different food types. Table 1.1 food type mass of carbohydrate in 100 g of food / g bread 40 cake 59 cheese 2 lentils 18 rice 25 tomato 3 (i) Identify the food type that contains the most carbohydrate. … [1] (ii) A man eats 200 g of bread and 50 g of cheese. Calculate the mass of carbohydrate he eats. mass of carbohydrate = … g [2] [Total: 11]

1(a) respiration ; sensitivity ; 2 1(b)(i) centre of X must be on liver ; 1 1(b)(ii) digestion ; absorption ; 2 1(c) no starch is made ; as light is needed for photosynthesis ; 2 1(d) phloem ; 1 1(e)(i) cake ; 1 1(e)(ii) (40 x 2) + (2 x 0.5) ; 81 (g) ; 2 (a) To earn marks, you must correctly identify 'respiration' for the breakdown of nutrient molecules and 'sensitivity' for detecting and responding to changes. (b)(i) You must draw the letter X with its center clearly on the liver in the provided diagram. (b)(ii) You need to state 'digestion' for the breakdown of large molecules and 'absorption' for small molecules moving into the blood. (c) To explain the results, you must state that no starch was made in the covered area and link this to light being necessary for photosynthesis.

1 (a) A blue dye is dissolved in water to make a blue liquid. Fig. 1.1 shows a cut plant stem in a beaker of the blue liquid. leaves plant stem blue liquid Fig. 1.1 The plant stem is left in the blue liquid for 24 hours. (i) Complete the sentences to explain why the leaves turn blue. Choose words from the list. Each word may be used once, more than once or not at all. cortex mesophyll phloem root hair stomata xylem The blue liquid moves up the plant stem in vessels called … . In the leaves, the blue liquid moves out of the vessels into … cells. Water in the blue liquid then diffuses out of the … into the air. [3] (ii) Fig. 1.2 shows the cross-section of the plant stem from Fig. 1.1. A B C D Fig. 1.2 The blue liquid only stains the transport vessels in the stem blue. Identify the letter in Fig. 1.2 that shows these transport vessels. … [1] (b) Plants make their own food. They make large molecules from smaller molecules. (i) The boxes on the left show some large molecules. The boxes on the right show the smaller molecules the large molecules are made from. Draw one straight line from each large molecule to the smaller molecules it is made from. large molecules smaller molecules oil amino acids protein fatty acids and glycerol starch glucose [2] (ii) Oils are stored in the seeds of a plant. A test is used to find the presence of oil in seeds. State the name of this test. … [1] (c) Oil from palm trees has many uses. Fig. 1.3 shows the mass of palm oil used worldwide between 2006 and 2016. 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 35 40 45 50 55 60 year mass of palm oil used worldwide / × 109 kg Fig. 1.3 (i) Use Fig. 1.3 to determine the mass of palm oil used worldwide in 2011. … ×109 kg [1] (ii) Areas of rainforest are removed to plant palm trees for oil. Describe how deforestation affects the animals living in the rainforest. … … … [2] [Total: 10]

1(a)(i) xylem ; mesophyll ; stomata ; 3 1(a)(ii) D ; 1 1(b)(i) oil amino acids protein fatty acids and glycerol starch glucose one correct ; three correct ; 2 1(b)(ii) ethanol (emulsion) ; 1 1(c)(i) 48 (× 109 kg ) ; 1 1(c)(ii) any two from: loss of habitat ; less food OR disruption to food, webs / chains ; less shelter ; migration (of species) ; extinction (of species) ; 2

1 (a) A blue dye is dissolved in water to make a blue liquid. Fig. 1.1 shows a cut plant stem in a beaker of the blue liquid. leaves plant stem blue liquid Fig. 1.1 The plant stem is left in the blue liquid for 24 hours. (i) Complete the sentences to explain why the leaves turn blue. Choose words from the list. Each word may be used once, more than once or not at all. cortex mesophyll phloem root hair stomata xylem The blue liquid moves up the plant stem in vessels called … . In the leaves, the blue liquid moves out of the vessels into … cells. Water in the blue liquid then diffuses out of the … into the air. [3] (ii) Fig. 1.2 shows the cross-section of the plant stem from Fig. 1.1. A B C D Fig. 1.2 The blue liquid only stains the transport vessels in the stem blue. Identify the letter in Fig. 1.2 that shows these transport vessels. … [1] (b) Plants make their own food. They make large molecules from smaller molecules. (i) The boxes on the left show some large molecules. The boxes on the right show the smaller molecules the large molecules are made from. Draw one straight line from each large molecule to the smaller molecules it is made from. large molecules smaller molecules oil amino acids protein fatty acids and glycerol starch glucose [2] (ii) Oils are stored in the seeds of a plant. A test is used to find the presence of oil in seeds. State the name of this test. … [1] (c) Oil from palm trees has many uses. Fig. 1.3 shows the mass of palm oil used worldwide between 2006 and 2016. 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 35 40 45 50 55 60 year mass of palm oil used worldwide / × 109 kg Fig. 1.3 (i) Use Fig. 1.3 to determine the mass of palm oil used worldwide in 2011. … ×109 kg [1] (ii) Areas of rainforest are removed to plant palm trees for oil. Describe how deforestation affects the animals living in the rainforest. … … … [2] [Total: 10]

1(a)(i) xylem ; mesophyll ; stomata ; 3 1(a)(ii) D ; 1 1(b)(i) oil amino acids protein fatty acids and glycerol starch glucose one correct ; three correct ; 2 1(b)(ii) ethanol (emulsion) ; 1 1(c)(i) 48 (× 109 kg ) ; 1 1(c)(ii) any two from: loss of habitat ; less food OR disruption to food, webs / chains ; less shelter ; migration (of species) ; extinction (of species) ; 2

4 (a) Table 4.1 shows the names and functions of some organs associated with the alimentary canal. Complete Table 4.1. Table 4.1 organ function pancreas produces enzymes used in the … intestine for digestion … produces bile which is stored in the gall bladder salivary gland makes saliva and releases it into the … for digestion [3] (b) Enzymes in saliva break down large starch molecules into smaller glucose molecules. (i) Glucose is a reducing sugar. State the name of the test solution used to identify the presence of a reducing sugar in food. … [1] (ii) Circle the name of one other large molecule made from glucose molecules. amino acids fatty acids glycerol glycogen [1] (c) Food labels show the quantities of nutrients found in the food. Fig. 4.2 shows a food label from a box of burgers. Energy Each grilled burger (94 g) contains Fat Sugars Salt Saturated fat 898 kJ 12 g 5.8 g 0.7 g 0.6 g Fig. 4.2 (i) A person eats two burgers. Calculate the mass of salt the person eats. … g [1] (ii) The label does not show a value for fibre. State the importance of eating fibre in a balanced diet. … … [1] [Total: 7]

4(a) small ; liver ; mouth ; 3 4(b)(i) Benedict's (solution) ; 1 4(b)(ii) glycogen ; 1 4(c)(i) 1.2 (g) ; 1 4(c)(ii) idea of keeping food moving (through alimentary canal) ; 1

Cambridge IGCSE Combined Science · 0653

IGCSE Combined Science (0653) Biological molecules past paper questions

Revise IGCSE Combined Science (0653) — Biological molecules with real Cambridge past-paper questions grouped by topic, each shown with its marking scheme. Working one topic at a time targets exactly the skill each question tests.

93 free questions from 2016–2021, each with its marking scheme. Open the full topical bank to filter by subtopic, paper, and year.

Biological molecules in IGCSE Combined Science 0653 exams, 2020–2025

Across 2020–2025, Biological molecules accounted for 95 questions worth 429 marks in Cambridge IGCSE Combined Science (0653) papers.

By year
Year	Questions	Marks
2020	15	83
2021	15	65
2022	16	71
2023	15	60
2024	18	67
2025	16	83

Most-tested subtopics

B4.1 Biological molecules376 marks

Appears in

Paper 1 · 36 qs
Paper 2 · 17 qs
Paper 3 · 21 qs
Paper 4 · 8 qs
Paper 5 · 7 qs
Paper 6 · 6 qs

All most-tested Combined Science topics

2021 May/Jun · Paper 3 · Q1 · 11 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q1 · 10 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q1 · 10 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q4 · 7 marks
Marking scheme
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2021 Feb/Mar · Paper 1 · Q3 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q3
Answer: C
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