2 (a) (i) List the chemical elements in a carbohydrate. … [1] (ii) State the name of one chemical element that is found in a protein but is not found in a carbohydrate. … [1] (b) Fig. 2.1 shows a variegated leaf which uses photosynthesis to make carbohydrates. A variegated leaf has green parts that contain chlorophyll and white parts that do not contain chlorophyll. white green Fig. 2.1 (i) State the word equation for photosynthesis. … [2] (ii) The carbohydrate produced by photosynthesis can be stored as starch in the leaf. A plant with variegated leaves used up its store of starch because it was placed in the dark. Explain why the plant used up its store of starch when it was placed in the dark. … … … … … [2] (iii) The plant with variegated leaves was then left in a warm, sunny place. After a few days, a leaf from this plant was removed and tested for starch. Predict the results of the starch test by placing ticks (3) in Table 2.1. Table 2.1 part of leaf starch present starch absent green white [1] (iv) State the name of the mineral ion that is needed to make chlorophyll. … [1] (c) Starch is a large molecule. The boxes on the left show the names of some other large molecules. The boxes on the right show some sentence endings. Draw five lines to make five correct sentences. large molecule sentence endings Cellulose is made from amino acids. DNA is made from fatty acids and glycerol. Glycogen is made from glucose. Oil is the genetic material. Protein [5] [Total: 13]

2(a)(i) carbon, hydrogen, oxygen ; 1 2(a)(ii) nitrogen ; 1 2(b)(i) carbon dioxide + water ; glucose + oxygen ; 2 2(b)(ii) any two from: no photosynthesis in the dark / light required, for photosynthesis / to make glucose / AW ; starch converted to glucose / AW ; (starch / glucose,) used, for respiration OR as a source of energy / AW ; 2 2(b)(iii) ; part of leaf starch present starch absent green  white  1 2(b)(iv) magnesium ; 1 2(c) ;;;;; large molecule sentence endings Cellulose is made from amino acids. DNA is made from fatty acids and glycerol. Glycogen is made from glucose. Oil is the genetic material. Protein 5 one mark for each correct line R each additional line To earn marks, you must list 'carbon, hydrogen, oxygen' for carbohydrates and 'nitrogen' for protein. For photosynthesis, you need to provide the correct word equation: 'carbon dioxide + water -> glucose + oxygen'. To explain starch use in the dark, you must state that no photosynthesis occurs, starch is converted to glucose, and this glucose is used for respiration or energy. For the table, you must correctly indicate starch present in the green part and absent in the white part. Finally, you must identify 'magnesium' as the element needed for chlorophyll and correctly match all five large molecules to their descriptions.

1 (a) (i) The main component of milk is a liquid that is an important solvent in the body. State the name of this solvent. … [1] (ii) Table 1.1 shows some of the nutrients found in human milk, the elements that make up the nutrients, the enzymes that digest them and the products of digestion. Complete Table 1.1. Table 1.1 nutrient elements enzyme products of digestion protein fat lactose (milk sugar) C, H, O galactose and glucose (simple sugars) [4] (b) Milk also contains vitamins and mineral salts. (i) Explain why vitamin D is important for the nutrition of children. … … … … … … … [3] (ii) Explain why iron is important in the diet. … … … … … … [2] (c) Rubella and kwashiorkor are two diseases that affect children. Rubella is a transmissible disease and kwashiorkor is a non-transmissible disease. (i) Define the term transmissible disease. … … … … [2] (ii) Explain why women should be vaccinated against rubella before they reach reproductive age. … … … … … … … … [4] (iii) Outline the causes of kwashiorkor. … … … … … [2] [Total: 18]

1(a)(i) water ; 1 1(a)(ii) nutrient elements enzyme products of digestion / products absorbed into blood protein C, H, O, N (S) AND protease / pepsin / trypsin amino acids ; fat C, H, O ; lipase fatty acids AND glycerol ; lactose (milk sugar) C, H, O lactase ; galactose and glucose (simple sugars) 4 elements for protein and fat for 1 mark enzyme and products for protein for 1 mark enzyme and products for fat for 1 mark enzyme for lactose for 1 mark 1(b)(i) any three from: needed for (growth / development / strengthening of) bones ; needed for (growth / development / strengthening of) teeth ; prevents rickets ; AVP ; 3 1(b)(ii) any two from: required to make haemoglobin / red blood cells ; for transport of oxygen ; prevents (iron-deficiency) anaemia ; AVP ; 2 1(c)(i) disease is caused by a pathogen ; (pathogen is) passed from one host to another ; 2 1(c)(ii) any four from: rubella is caused by a virus ; (virus) can cross the placenta ; (virus) can affect embryo / fetus ; can cause serious, disease / damage / death, to baby / offspring ; vaccination stimulates, long-lasting / active, immunity (in the mother) ; (immunity gained) before they become pregnant ; AVP ; 4 1(c)(iii) not enough protein (in the diet) ; adequate energy (in the diet) ; inadequate diet after breast feeding finishes / AW ; 2

6 Enzymes are catalysts. (a) Define the term catalyst. … … … [2] (b) Fig. 6.1 shows diagrams of three enzymes and eight different substrates. 1 3 W P R S T U V Q 2 Fig. 6.1 (i) State the letter of the substrate that will be broken down by enzyme 1. … [1] (ii) Explain, in terms of enzyme structure, the reason for your choice in 6(b)(i). … … … … … [2] (c) Table 6.1 lists some enzymes and the reactions that they catalyse. Complete Table 6.1. Table 6.1 enzyme reaction maltase breakdown of maltose to … … breakdown of proteins to amino acids lipase breakdown of fats to … and … … breakdown of lactose to simpler sugars … insertion of a short length of DNA into a plasmid restriction enzyme … [6] [Total: 11]

5(c) any six from: 1 eutrophication ; 2 increased growth of, plants / producers / algae ; 3 plants / producers, compete with each other for light / AW , 4 plants / producers, die or plants / producers, are decomposed ; 5 increase in, decomposers / bacteria ; 6 bacteria / decomposers, use / absorb, (dissolved) oxygen in water ; 7 decrease in concentration of (dissolved) oxygen ; reasons for reduction in biodiversity: 8 death of, (named) animals / fish / invertebrates (due to lack of dissolved oxygen) ; 9 decrease in, food / energy, available in, ecosystem / AW ; 10 ref to, pathogens / disease / toxins / poisons ; 11 ref to aerobic respiration (in either section) 12 AVP ; 6 MP2 A algal bloom MP3 A no photosynthesis as no light MP8 A if linked to MP7 MP9 A disruption of food, chains / webs 6(a) (substance) that increases the rate of (chemical) reactions ; not changed, during / by, the reaction ; 2 6(b)(i) T ; 1 6(b)(ii) (T) fits into / binds to, enzyme / active site ; active site has a complementary shape (to T) / active site and T are complementary ; 2 A T and enzyme form an, enzyme- substrate complex / ESC 6(c) glucose ; pepsin / trypsin / protease ; fatty acids and glycerol ; lactase ; (DNA) ligase ; cuts / breaks / digests, DNA (molecule / strand(s)) / gene / plasmid ; 6 A other named proteases A makes sticky ends

2 Fig. 2.1 is a photograph of a flower from the wind-pollinated grass plant, Briza maxima. Fig. 2.1 (a) (i) Draw a large diagram of the flower in Fig. 2.1. [4] (ii) Fig. 2.2 is a photomicrograph of grass pollen grains. P Q magnification ×1500 Fig. 2.2 Measure the length of line PQ on Fig. 2.2. length of PQ … mm Calculate the actual length of the pollen grain using the formula and your measurement. magnification = length of line PQ actual length of the pollen grain Give your answer in millimetres and to two decimal places. Space for working. … mm [3] (b) Scientists investigated the effect of wind speed on the average distance travelled by single pollen grains and groups of five pollen grains joined to form a clump. The pollen grains were dropped from a height of 2 m. The results of the investigation are shown in Table 2.1. Table 2.1 wind speed / m per s average distance travelled by single pollen grains / m average distance travelled by clumps of five pollen grains / m 0.0 0 0 0.2 38 21 0.4 81 39 0.6 118 55 0.8 154 70 (i) Calculate the percentage decrease in the average distance travelled when the pollen grains fell as a clump compared to a single pollen grain, at a wind speed of 0.6 m per s. Give your answer to two significant figures. Space for working. …% [3] (ii) Plot a line graph on the grid of the data in Table 2.1. Include both sets of data and a key. [5] (iii) Use your graph to estimate the average distance travelled by single pollen grains at a wind speed of 0.5 m per s. Show on your graph how you obtained your estimate. … m [2] (iv) Successful pollination results in fertilisation and the production of seeds. State the test that would show that the seeds contain protein. Include the result of a positive test. test … positive test result … [2] (c) (i) Plan an investigation to determine the effect of temperature on the rate of transpiration from leaves. You may wish to include the apparatus listed and any other apparatus that you think is suitable in your plan: • leafy plants • electronic balance • thermometer • string • stop-clock … … … … … … … … … … … … … [6] (ii) Humidity also affects the rate of transpiration from leaves. Suggest how you could change the humidity that the leaves are exposed to in a transpiration investigation. … … … [1] [Total: 26]

2(a)(i) 1 single clear lines for outline ; 2 uses at least half available space (70+ mm length without stalk) ; 3 detail 1 at least 6 sections, indicated with lines, on either side ; 4 detail 2 at least 3 overlapping sections or indication of ‘zig zag line’ down the centre ; 4 2(a)(ii) 62 (mm) ±1 mm ; 0.04 (mm) ;; 3 MP1 correct measurement of line PQ MP2 correct substitution (62 ÷ 1500) or 0.04133r MP3 correct rounding to two decimal places ecf MP2 and MP3 if previous MP incorrect

9 Four foods were tested for each of these nutrients: fat (using the ethanol emulsion test) protein (using the biuret test) reducing sugar (using Benedict’s solution). Which food contains protein and fat? colour of result of food test purple brick-red milky-white A key B = nutrient present C = nutrient absent D

Answer: A To earn the mark, a student must correctly identify the food (A) that shows a positive result for both protein (purple) and fat (milky-white) tests.

Cambridge IGCSE Biology · 0610

IGCSE Biology (0610) Biological molecules past paper questions

Questions on carbohydrates, proteins, and fats and the chemical tests that identify them.

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

Biological molecules in IGCSE Biology 0610 exams, 2020–2025

Across 2020–2025, Biological molecules accounted for 166 questions worth 1,154 marks in Cambridge IGCSE Biology (0610) papers.

By year
Year	Questions	Marks
2020	28	184
2021	22	151
2022	25	186
2023	33	208
2024	34	265
2025	24	160

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4.1 Biological molecules1055 marks

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Paper 1 · 53 qs
Paper 2 · 46 qs
Paper 3 · 21 qs
Paper 4 · 15 qs
Paper 5 · 16 qs
Paper 6 · 15 qs

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2021 May/Jun · Paper 3 · Q2 · 13 marks
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2021 May/Jun · Paper 4 · Q1 · 18 marks
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2021 Oct/Nov · Paper 4 · Q6 · 11 marks
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2021 Oct/Nov · Paper 5 · Q2 · 26 marks
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2021 Feb/Mar · Paper 1 · Q9 · 1 mark
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Mark scheme — 2021 Paper 1 Q9
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