Water, carbohydrates and lipids: Edexcel International A Level Biology questions

Every Edexcel International A Level Biology exam question on Water, carbohydrates and lipids (specification points 1.1–1.5), 2019–2025, with its mark scheme and examiner’s report.

All 97 questions on Water, carbohydrates and lipids, as a list

June 2025, AS Unit 3, Q3(a)(i) (3 marks): Describe the structure of starch. (3)
June 2025, AS Unit 3, Q3(a)(ii) (3 marks): Explain how colour standards can be used as a semi‑quantitative method of estimating the concentration of starch in a sample. (3)
June 2025, AS Unit 3, Q3(b)(ii) (3 marks): Describe how to determine the total mass of starch present in section B of this root. (3)
June 2025, AS Unit 3, Q3(b)(iii) (3 marks): Describe how this investigation could be extended to determine the variability in the concentration of starch in different cassava roots. (3)
January 2025, AS Unit 1, Q1(a) (1 mark): Which of the following statements about water are correct? 1. A single molecule of water is composed of an oxygen atom joined to two hydrogen atoms by hydrogen
January 2025, AS Unit 1, Q1(b) (3 marks): The table shows some information about the structure of amylose and amylopectin. Put one cross in the appropriate box in each row to show whether the structure
October 2024, AS Unit 1, Q8(a) (3 marks): Avocados are high in unsaturated fatty acids and low in saturated fatty acids. Compare and contrast the structure of an unsaturated fatty acid and the structure
October 2024, AS Unit 3, Q1(a) (3 marks): Describe the structure of starch. (3)
October 2024, AS Unit 3, Q1(b)(i) (2 marks): Explain the effect this will have on the mass of starch produced in maize plants. (2)
June 2024, AS Unit 1, Q6(a) (3 marks): The diagram shows two glucose molecules. Complete the diagram to show how these two molecules join by a glycosidic bond to form two products. (3) CH2OH CH2OH C
June 2024, AS Unit 1, Q6(b)(i) (2 marks): The diagram shows part of an amylopectin molecule. Key glucose molecule joined by 1–4 glycosidic bonds glucose molecule joined by 1–4 and 1–6 glycosidic bonds D
June 2024, AS Unit 1, Q6(c)(i) (3 marks): Suggest how disaccharides and oligosaccharides are broken down in the small intestine. Give reasons for your answer. (3)
January 2024, AS Unit 1, Q4(a)(i) (2 marks): Explain the dipole nature of water. (2)
January 2024, AS Unit 1, Q4(a)(ii) (1 mark): The diagram shows three water molecules. Complete the diagram to show a hydrogen bond between two water molecules. (1) O H H H O H O H H
January 2024, AS Unit 1, Q4(b) (1 mark): Water plays a role as a solvent. Sodium chloride dissolves in water. The diagram shows a sodium ion (Na+). Complete the diagram to show the arrangement of two w
January 2024, AS Unit 1, Q4(c) (4 marks): Temperature affects the solubility of chemicals in water. The graph shows the effect of temperature on the solubility of four chemicals, A, B, C and D. 90 chemi
January 2024, AS Unit 1, Q5(c)(i) (1 mark): Which row of the table describes the action of amylase? (1) Type of reaction Glycosidic bond broken 1 – 4 A condensation B condensation 1 – 6 C hydrolysis 1 – 4
January 2024, AS Unit 1, Q5(c)(ii) (2 marks): People with low levels of amylase in their saliva were found to lose weight more easily. Suggest why these people lost weight more easily. (2)
January 2024, AS Unit 1, Q8(a) (2 marks): Tropical sprue is a disorder that limits the absorption of nutrients into the blood. Consumption of unsaturated lipids has been proposed as a cause of tropical
October 2023, AS Unit 1, Q6(a) (3 marks): The table shows some of the bonds found in amylose and amylopectin. Put one cross in the appropriate box in each row to show whether the bond is present in thes
October 2023, AS Unit 1, Q6(b) (2 marks): When sources of starch are heated in water, amylose moves into the water. The graph shows the percentage of amylose that is lost from four sources of starch at
October 2023, AS Unit 1, Q6(c)(i) (3 marks): Compare and contrast the effects of temperature on the loss of amylose and amylopectin from rice. (3)
October 2023, AS Unit 1, Q6(c)(ii) (3 marks): The investigation continued by adding a replacement liquid to finish cooking the rice. The hardness and stickiness of the cooked rice was determined for each re
October 2023, AS Unit 1, Q6(c)(iii) (2 marks): Suggest why rice should be cooked in a measured volume of water, with the lid on, until all the cooking liquid has been absorbed. Use the information in the tab
October 2023, AS Unit 3, Q2(a)(i) (2 marks): Describe how a urine sample can be tested for glucose. (2)
October 2023, AS Unit 3, Q2(a)(ii) (2 marks): Complete the table of results from tests on standard glucose solutions. (2) Glucose concentration Appearance Glucose quantity / g dm–3 Blue 0.0 None Green with
October 2023, AS Unit 3, Q2(b)(iii) (3 marks): Comment on the conclusion that urine glucose concentration is a good indicator of the blood glucose level. Use the information in the table and in your graph to
October 2023, Unit 4, Q4(a) (1 mark): During the first few days after birth, the milk produced is called colostrum. By two weeks, the composition of the milk has changed and it is called mature brea
June 2023, AS Unit 1, Q3(a)(i) (1 mark): The diagram shows a molecule of glucose and a molecule of fructose. Carbon 1 on the glucose and carbon 2 on the fructose are numbered. Complete the diagram to s
June 2023, AS Unit 1, Q3(a)(ii) (2 marks): Complete the formula equation for the reaction that makes sucrose from glucose and fructose. (2) C6H12O6 + C6H12O6
June 2023, AS Unit 1, Q3(b)(i) (1 mark): Give a reason why the colour intensity is directly proportional to the concentration of sucrose. (1)
June 2023, AS Unit 1, Q3(b)(ii) (1 mark): Suggest why the line does not start at the origin of the graph. (1)
June 2023, AS Unit 1, Q3(b)(iii) (1 mark): State why the concentration of maltose and lactose cannot be measured using this test. (1)
June 2023, AS Unit 1, Q6(b) (1 mark): Which row of the table is correct for an unsaturated fatty acid? (1) Carbon : hydrogen ratio Contains carbon–carbon compared with a saturated double bonds fatty
January 2023, AS Unit 1, Q1(a) (2 marks): Draw a diagram of a water molecule to show its dipole nature. (2)
January 2023, AS Unit 1, Q1(b) (3 marks): The table gives some statements about carbohydrates. For each statement, put one cross in the appropriate box in each row to match the statement to the correct
January 2023, AS Unit 1, Q7(a) (2 marks): Triglycerides are fats. Describe the structure of a triglyceride. (2)
October 2022, AS Unit 1, Q7(d) (3 marks): Insulin lowers the levels of glucose in the blood. This glucose is taken up by the liver and stored as glycogen. Compare and contrast the structure of glucose w
June 2022, AS Unit 1, Q1 (5 marks): Water is an important biological molecule. Read through the following description of water. Complete the description by writing the most appropriate word on the
June 2022, AS Unit 1, Q7(b)(ii) (1 mark): Which row in the table describes an unsaturated fatty acid compared with a saturated fatty acid with the same number of carbon atoms? (1) Has double bonds betwe
June 2022, AS Unit 3, Q3(a) (4 marks): Describe how the data in the table could have been obtained using a 1% starch solution. (4)
June 2022, AS Unit 3, Q3(b) (4 marks): The table shows the results for the four potato varieties. Potato variety Colour King Edward black Nicola very pale blue Purple Congo pale blue Russet dark blue
June 2022, AS Unit 3, Q3(c) (2 marks): Suggest how this investigation could be adapted to produce quantitative data. (2)
June 2022, AS Unit 3, Q3(d)(i) (2 marks): Calculate the rate of decrease in starch content from day 15 to day 23. Include units in your answer. (2) Answer
June 2022, AS Unit 3, Q3(d)(ii) (2 marks): Describe the changes in starch content during the 23 days of this investigation. (2)
June 2022, AS Unit 3, Q3(d)(iii) (2 marks): Sketch a graph to show the soluble sugar content of these bananas during storage. (2) Soluble sugar content / a.u. 0 5 10 15 20 25 Time in storage / days
January 2022, AS Unit 1, Q1(a) (1 mark): This plant grows from a bulb. The bulb contains starch as an energy storage molecule for the crocus. How many of the following statements are correct for starch
January 2022, AS Unit 1, Q1(b)(i) (4 marks): Read through the following description of some disaccharides. Complete the description by writing the most appropriate word on the dotted lines. (4) Disaccharid
January 2022, AS Unit 1, Q1(b)(ii) (1 mark): Gentiobiose is formed from two identical monosaccharides. Name the type of reaction that joins these monosaccharides together in the formation of gentiobiose. (
January 2022, AS Unit 1, Q1(b)(iii) (1 mark): The molecular mass of each of the monosaccharides in gentiobiose is 180. The table shows the molecular mass of the elements present in the monosaccharides. Elem
October 2021, AS Unit 1, Q4(a)(i) (1 mark): The sugars in the nectar are fructose, glucose and sucrose. Which of these contain glycosidic bonds? (1) A fructose only B sucrose only C fructose and glucose D
October 2021, AS Unit 1, Q4(a)(iii) (1 mark): Which row of the table describes a saturated lipid? (1) carbon-carbon double bonds carbon : hydrogen ratio higher than in an unsaturated A absent fatty acid cha
June 2021, AS Unit 1, Q1(a) (4 marks): Polymers are large molecules made of monomers. The table gives information about some of these polymers. Complete the table by filling in the empty boxes with e
June 2021, AS Unit 1, Q1(b) (3 marks): Triglycerides are lipids. Describe how an unsaturated triglyceride is synthesised. (3)
June 2021, AS Unit 1, Q2(a) (1 mark): Which polysaccharide does the liver store? (1) A amylopectin B cellulose C glycogen D starch
June 2021, AS Unit 1, Q2(b) (1 mark): Blood glucose levels can become high following the digestion of carbohydrates. Which of the following can be digested to release glucose? (1) A both fructose an
June 2021, Unit 4, Q6(a) (4 marks): Carbon is found in carbohydrates. The table shows some carbohydrates that may be found in plants and animals. For each carbohydrate, put one cross in the approp
January 2021, AS Unit 1, Q3(a)(i) (1 mark): Which is the correct statement about the formation of glycogen? (1) A α glucose molecules join together by a condensation reaction B α glucose molecules join to
January 2021, AS Unit 1, Q3(a)(ii) (1 mark): Name the bond that joins two glucose molecules together. (1)
January 2021, AS Unit 1, Q3(a)(iii) (3 marks): Explain how the structure of glycogen relates to its role as an energy storage molecule. (3)
January 2021, AS Unit 1, Q5(c)(i) (2 marks): Describe the dipolar nature of water. (2)
January 2021, AS Unit 1, Q8(a)(i) (1 mark): Which are the products of lactose digestion? (1) A fructose and galactose B fructose and glucose C galactose and glucose D glucose and glucose
January 2021, Unit 4, Q8(b)(i) (2 marks): Complete the table to show the ratio of the concentrations of the four types of carbohydrate. (2) Type of carbohydrate Ratio monosaccharide disaccharide trisacc
January 2021, Unit 4, Q8(b)(ii) (1 mark): Which row of the table shows the carbohydrates with the median concentration and modal concentration in quince juice? (1) Median Mode A raffinose fructose B raf
October 2020, AS Unit 1, Q5(b)(i) (1 mark): Which glycosidic bonds are responsible for the branching in glucomannan? (1) A 1‑4 only B 1‑6 only C both 1‑4 and 1‑6 D neither 1‑4 nor 1‑6
October 2020, AS Unit 1, Q5(b)(ii) (1 mark): In the presence of water, glucomannan swells to form a semi‑solid gel. The diagram shows a stomach with glucomannan present and a stomach without glucomannan. K
October 2020, AS Unit 1, Q5(b)(iii) (2 marks): If glucomannan could be digested it would cause a gain in weight. Explain why glucomannan could cause a gain in weight. (2)
October 2020, AS Unit 1, Q8(a) (3 marks): Compare and contrast the structure of a triglyceride and a phospholipid. (3)
October 2020, AS Unit 3, Q2(a)(i) (2 marks): Describe the structure of sucrose. (2)
October 2020, Unit 6, Q1(a) (2 marks): The tissues of the tubers contain starch molecules. Explain why starch is an energy storage molecule. (2)
January 2020, AS Unit 1, Q3(a)(ii) (1 mark): Which of the following are the monosaccharides present in lactose? (1) A fructose and sucrose B galactose and glucose C glucose and fructose D sucrose and galac
January 2020, AS Unit 1, Q4(a)(i) (3 marks): Compare and contrast the effect of temperature on the solubilities of sodium chloride and glucose in water. (3)
January 2020, AS Unit 1, Q4(a)(ii) (2 marks): The formula mass of sodium chloride is 58.44. Calculate the molecular mass of glucose, using the information in the table. (2) Element Atomic mass carbon 12 hyd
January 2020, AS Unit 1, Q4(a)(iii) (1 mark): Calculate how many times greater the molecular mass of glucose is than the formula mass of sodium chloride. (1) Answer
January 2020, AS Unit 1, Q4(a)(iv) (2 marks): Suggest why there is a difference in the solubility of sodium chloride and glucose in water. (2)
January 2020, AS Unit 1, Q4(b) (2 marks): Explain why fatty acids are less soluble in blood than glucose and sodium chloride. (2)
January 2020, Unit 4, Q2(b) (1 mark): Some bacteria have been discovered that can break down one type of plastic, the polymer polyethylene terephthalate (PET). This polymer is made from the monomer
June 2019, AS Unit 1, Q1(a) (2 marks): Draw a diagram of a water molecule to show its dipole nature. (2)
June 2019, AS Unit 1, Q1(b)(i) (3 marks): Describe the effect of temperature on the solubility of these three salts. (3)
June 2019, AS Unit 1, Q1(b)(ii) (1 mark): How many times more soluble is salt G than salt H at 30 °C? (1) A 15.00 B 1.67 C 1.50 D 0.60
June 2019, AS Unit 1, Q2(a)(i) (1 mark): What is the ratio of glycerol to fatty acid in a triglyceride molecule? (1) A 1:1 B 1:3 C 3:1 D 3:3
June 2019, AS Unit 1, Q2(a)(ii) (1 mark): Which diagram shows the bond that joins a glycerol molecule to a fatty acid in a triglyceride? (1) H O A C N C H OH B C N C O C C O C OH D C O C
June 2019, AS Unit 1, Q2(a)(iii) (2 marks): The table gives some information about four fatty acids. Number of double bonds Fatty acid Number of carbon atoms between carbon atoms butyric 0 4 stearic 0 18
June 2019, AS Unit 1, Q5(a)(i) (1 mark): Which row of the table shows which of these sugars are monosaccharides and which are disaccharides? (1) Monosaccharides Disaccharides A fructose only glucose an
June 2019, AS Unit 1, Q5(a)(ii) (1 mark): Which type of bond joins two monosaccharides together to form a disaccharide? (1) A ester B glycosidic C peptide D phosphodiester
June 2019, AS Unit 1, Q5(b)(i) (2 marks): Calculate the mean concentration of glucose in these three pineapples. Give your answer in g dm−3. (2) Answer g dm−3
June 2019, AS Unit 3, Q2(a)(i) (2 marks): Describe how a test for reducing sugars is carried out. (2)
June 2019, AS Unit 3, Q2(a)(ii) (3 marks): Explain how this investigation should be carried out to give a semi‑quantitative estimate of the concentration of the reducing sugars by comparing the colour of
June 2019, AS Unit 3, Q2(a)(iii) (2 marks): It was assumed that the extract contained all the reducing sugars from the food sample. Suggest how this assumption could be tested. (2)
June 2019, AS Unit 3, Q2(c)(i) (3 marks): Explain which food extract would leave the least blue solution when the precipitate is removed. (3)
June 2019, AS Unit 3, Q2(c)(ii) (4 marks): Devise a procedure to determine the concentration of reducing sugars in a sweet potato. (4)
January 2019, AS Unit 1, Q1(a)(i) (1 mark): Which formula is correct for a monosaccharide? (1) A CnHnO2n B CnH2nOn C C2nHnOn D C2nH2nOn
January 2019, AS Unit 1, Q1(a)(ii) (1 mark): Name the reaction that joins two monosaccharides together to form a disaccharide. (1)
January 2019, AS Unit 1, Q1(b)(i) (1 mark): to (iv)? (4) (i) present in cow’s milk A amylose B galactose C lactose disaccharides D sucrose
January 2019, AS Unit 1, Q1(b)(ii) (1 mark): contains only glucose subunits A amylopectin B galactose C maltose carbohydrates D sucrose
January 2019, AS Unit 1, Q1(b)(iii) (1 mark): energy store in animals A amylose B fructose C glycogen polysaccharides D sucrose
January 2019, AS Unit 1, Q1(b)(iv) (1 mark): 1 - 6 glycosidic bonds present A amylose B amylopectin C fructose D maltose

Questions, mark schemes and examiner’s reports are © Pearson Edexcel, from their published past papers. Plumi isn’t affiliated with any exam board. Want whole papers? Every Edexcel International A Level Biology paper.

Rather write your answers by hand on iPad? Plumi marks them against the same mark schemes.

3,127 questions