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Chemical elements are joined together to form biological compounds: Eduqas A‑Level Biology questions

Every Eduqas A-Level Biology exam question on C.1 Chemical elements are joined together to form biological compounds, 2016–2025, with its mark scheme and examiner’s report.

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2,061 questions

  1. Q3(a)(i)

    June 2025 · Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 3(a)(i): State which two of the macronutrients listed above are required to produce the amino acids involved in cross-linking polypeptide chains. [2]

  2. Q3(a)(ii)

    June 2025 · Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 3(a)(ii): State one role of each of the following elements in plants. [2] calcium magnesium

  3. Q3(b)(i)

    June 2025 · Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 3(b)(i): An experiment was carried out to investigate the effects of some micronutrient deficiencies on duckweed (Lemna minor). This is a simple, aquatic plant that floa

  4. Q3(b)(ii)

    June 2025 · Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 3(b)(ii): Explain one reason why the top of the beaker was covered with clear plastic film. [2]

  5. Q3(b)(iii)

    June 2025 · Component 1

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 3(b)(iii): Suggest the colour of leaves given a leaf colour score of 0. [1] The results of the experiment are shown in Table 3.2. Table 3.2 Mean results Nutrient medium –

  6. Q3(b)(iv)

    June 2025 · Component 1

    3 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 3(b)(iv): Use Table 3.2 to plot a bar chart of the mean dry mass of L. minor harvested for each nutrient medium on the grid below. [3]

  7. Q4(d)(ii)

    June 2025 · Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 4(d)(ii): Laccase is a soluble, globular protein. A ribbon diagram of its structure is shown in Image 4.3 Image 4.3 X Identify the secondary protein structure labelled X

  8. Q5(b)(ii)

    June 2025 · Component 1

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 1, question 5(b)(ii): Both citrate and isocitrate contain three of the same functional group. This functional group is also found in amino acids. State the name and formula of this f

  9. Q1(b)(iii)

    June 2025 · Component 2

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 2, question 1(b)(iii): Use only the information in Table 1.4 to identify two ways in which human milk is more beneficial to feed to a human baby than cow milk. [2] I. II.

  10. Q3(a)

    June 2025 · Component 3

    4 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 3, question 3(a): Sucrose is a disaccharide. Raffinose is a trisaccharide made up of galactose, glucose and fructose. Both sucrose and raffinose contain glycosidic bonds. Raffino

  11. Q4(c)(iii)

    June 2025 · Component 3

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 Component 3, question 4(c)(iii): Trypsin hydrolyses peptide bonds within polypeptides. Draw an arrow on Image 4.3 to identify one peptide bond. [1]

  12. Q1(a)(i)

    June 2025 · AS Component 1

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(a)(i): State the names of the molecules labelled X and Y in Image 1.1. [1] X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

  13. Q1(a)(ii)

    June 2025 · AS Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(a)(ii): With reference to Image 1.1, explain why up to four structurally different molecules could be combined to form a lipid of this type. [2]

  14. Q1(a)(iii)

    June 2025 · AS Component 1

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(a)(iii): Draw the structural formula of the molecule labelled X in Image 1.1 before the condensation reactions took place. [1]

  15. Q1(b)(i)

    June 2025 · AS Component 1

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(b)(i): Complete Table 1.2 to show whether molecules A to D would be solid or liquid at a room temperature of 20 °C. [1]

  16. Q1(b)(ii)

    June 2025 · AS Component 1

    3 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(b)(ii): Image 1.3 shows the structural formula of molecule A. Image 1.3 O H H H H H H H H H H H H H H H H H HO C C C C C C C C C C C C C C C C C C H H H H H H H H H H H

  17. Q1(b)(iii)

    June 2025 · AS Component 1

    2 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(b)(iii): Suggest and explain how eating lipids containing only molecule D in Table 1.2 may impact human health. [2]

  18. Q1(b)(iv)

    June 2025 · AS Component 1

    3 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 1(b)(iv): In order to improve human health, people who drink milk have been advised to drink skimmed or plant-based milks. I. Describe how ethanol can be used to show the

  19. Q5(b)(iii)

    June 2025 · AS Component 1

    3 marksC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2025 AS Component 1, question 5(b)(iii): I. State the highest level of protein structure that would be present in the functional protein. [1] II. Explain how this structure is maintained. [2]

  20. Q3(c)(i)

    June 2024 · Component 1

    1 markC.1 Chemical elements are joined together to form biological compounds
    The whole paper ↗
    June 2024 Component 1, question 3(c)(i): Explain why glucose and fructose are known as structural isomers of each other.  [1] Image 3.4 shows the hydrolysis of sucrose catalysed by the enzyme sucrase.
All 128 questions on Chemical elements are joined together to form biological compounds, as a list
  1. June 2025, Component 1, Q3(a)(i) (2 marks): State which two of the macronutrients listed above are required to produce the amino acids involved in cross-linking polypeptide chains. [2]
  2. June 2025, Component 1, Q3(a)(ii) (2 marks): State one role of each of the following elements in plants. [2] calcium magnesium
  3. June 2025, Component 1, Q3(b)(i) (2 marks): An experiment was carried out to investigate the effects of some micronutrient deficiencies on duckweed (Lemna minor). This is a simple, aquatic plant that floa
  4. June 2025, Component 1, Q3(b)(ii) (2 marks): Explain one reason why the top of the beaker was covered with clear plastic film. [2]
  5. June 2025, Component 1, Q3(b)(iii) (1 mark): Suggest the colour of leaves given a leaf colour score of 0. [1] The results of the experiment are shown in Table 3.2. Table 3.2 Mean results Nutrient medium –
  6. June 2025, Component 1, Q3(b)(iv) (3 marks): Use Table 3.2 to plot a bar chart of the mean dry mass of L. minor harvested for each nutrient medium on the grid below. [3]
  7. June 2025, Component 1, Q4(d)(ii) (2 marks): Laccase is a soluble, globular protein. A ribbon diagram of its structure is shown in Image 4.3 Image 4.3 X Identify the secondary protein structure labelled X
  8. June 2025, Component 1, Q5(b)(ii) (1 mark): Both citrate and isocitrate contain three of the same functional group. This functional group is also found in amino acids. State the name and formula of this f
  9. June 2025, Component 2, Q1(b)(iii) (2 marks): Use only the information in Table 1.4 to identify two ways in which human milk is more beneficial to feed to a human baby than cow milk. [2] I. II.
  10. June 2025, Component 3, Q3(a) (4 marks): Sucrose is a disaccharide. Raffinose is a trisaccharide made up of galactose, glucose and fructose. Both sucrose and raffinose contain glycosidic bonds. Raffino
  11. June 2025, Component 3, Q4(c)(iii) (1 mark): Trypsin hydrolyses peptide bonds within polypeptides. Draw an arrow on Image 4.3 to identify one peptide bond. [1]
  12. June 2025, AS Component 1, Q1(a)(i) (1 mark): State the names of the molecules labelled X and Y in Image 1.1. [1] X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
  13. June 2025, AS Component 1, Q1(a)(ii) (2 marks): With reference to Image 1.1, explain why up to four structurally different molecules could be combined to form a lipid of this type. [2]
  14. June 2025, AS Component 1, Q1(a)(iii) (1 mark): Draw the structural formula of the molecule labelled X in Image 1.1 before the condensation reactions took place. [1]
  15. June 2025, AS Component 1, Q1(b)(i) (1 mark): Complete Table 1.2 to show whether molecules A to D would be solid or liquid at a room temperature of 20 °C. [1]
  16. June 2025, AS Component 1, Q1(b)(ii) (3 marks): Image 1.3 shows the structural formula of molecule A. Image 1.3 O H H H H H H H H H H H H H H H H H HO C C C C C C C C C C C C C C C C C C H H H H H H H H H H H
  17. June 2025, AS Component 1, Q1(b)(iii) (2 marks): Suggest and explain how eating lipids containing only molecule D in Table 1.2 may impact human health. [2]
  18. June 2025, AS Component 1, Q1(b)(iv) (3 marks): In order to improve human health, people who drink milk have been advised to drink skimmed or plant-based milks. I. Describe how ethanol can be used to show the
  19. June 2025, AS Component 1, Q5(b)(iii) (3 marks): I. State the highest level of protein structure that would be present in the functional protein. [1] II. Explain how this structure is maintained. [2]
  20. June 2024, Component 1, Q3(c)(i) (1 mark): Explain why glucose and fructose are known as structural isomers of each other.  [1] Image 3.4 shows the hydrolysis of sucrose catalysed by the enzyme sucrase.
  21. June 2024, Component 1, Q3(c)(ii) (2 marks): Name reactant X, monosaccharide Y and monosaccharide Z in Image 3.4. [2] reactant X  monosaccharide Y  monosaccharide Z 
  22. June 2024, Component 1, Q3(c)(iii) (1 mark): Give one reason why using sucrose as the respiratory substrate resulted in fewer bubbles being produced than when using glucose. [1] Lactose is the sugar found
  23. June 2024, Component 1, Q4(a)(i) (1 mark): Name the inorganic ion X found in chlorophyll a. [1]
  24. June 2024, Component 1, Q4(a)(ii) (1 mark): Hydrocarbons, such as carotene, contain atoms of carbon and hydrogen only. Apart from the presence of ion X, explain why chlorophyll a cannot be classified as a
  25. June 2024, Component 2, Q2(b)(i) (1 mark): Explain the meaning of quaternary structure. [1] Beta-globin (β-globin) is one of the sub-units found in the haemoglobin molecule. It is coded for by the β-glob
  26. June 2024, Component 2, Q5(a)(i) (1 mark): State one difference between saturated and unsaturated fatty acids.  [1]
  27. June 2024, Component 2, Q5(a)(ii) (1 mark): Describe a chemical test to show the presence of protein in the elaiosome.  [1]
  28. June 2024, Component 3, Q5(a)(ii) (2 marks): Describe what is meant by the term hormone and explain why the tertiary structure of this protein is important in its function as a hormone. [2]
  29. June 2024, AS Component 1, Q1(a)(i) (2 marks): State the name of the bond which forms between two water molecules. Explain why this bond forms. [2]
  30. June 2024, AS Component 1, Q1(a)(ii) (2 marks): Transport of water in plants relies on some of the properties of water and the bonds between the water molecules. State two properties of water which allow the
  31. June 2024, AS Component 1, Q1(b) (2 marks): Complete the table to describe the advantages of the following properties of water to living organisms. [2] Property of water Advantage to living organisms Take
  32. June 2024, AS Component 1, Q3(a)(i) (1 mark): State which isomer of glucose is present in cellulose. [1]
  33. June 2024, AS Component 1, Q3(a)(ii) (3 marks): Describe how the arrangement of the glucose molecules gives strength to the cell wall. [3] Cellulose fibres in the plant cell wall are held together by another
  34. June 2024, AS Component 1, Q3(a)(iii) (3 marks): Using Image 3.1 and your knowledge of polysaccharides: I. State the reaction involved in the formation of both cellulose and pectin. [1] II. Give one similarity
  35. June 2023, Component 1, Q3(a)(i) (1 mark): The enzyme hexokinase catalyses the addition of a phosphate group to a molecule of glucose and can accept both alpha and beta glucose isomers as substrates. The
  36. June 2023, Component 1, Q3(a)(iii) (1 mark): Hexokinase includes a magnesium ion to catalyse the addition of a phosphate group to glucose. State one other use of magnesium ions in eukaryotic cells. [1]
  37. June 2023, Component 1, Q4(a)(i) (2 marks): Name two types of compounds in the fish food that contain nitrogen atoms. [2] Graph 4 shows the concentration of three nitrogen-containing compounds found in th
  38. June 2023, Component 2, Q4(b)(ii) (2 marks): Testosterone is classified as a lipid. Use Image 4.2 and the information given to explain why testosterone is not classified as a: I. carbohydrate; [1] II. prot
  39. June 2023, Component 3, Q3(d)(i) (1 mark): State the name given to the structure of a protein which is made from different polypeptide chains linked together. [1]
  40. June 2023, AS Component 1, Q1(a) (2 marks): Inorganic ions are found in many of the main biological molecules in living organisms. Complete Table 1.1 to state one role of each of the inorganic ions shown.
  41. June 2023, AS Component 1, Q1(b)(i) (2 marks): State two structural differences between the two types of proteins shown in Image 1.2. [2]
  42. June 2023, AS Component 1, Q1(b)(ii) (1 mark): Polypeptides are polymers of amino acids joined by peptide bonds. Name the type of reaction which takes place to form these bonds. [1]
  43. June 2023, AS Component 1, Q1(c)(i) (2 marks): The enzyme acid phosphatase is a protein. Name the reagent that would be used to test for protein and the colour produced by a positive result. [2] The concentr
  44. June 2023, AS Component 1, Q1(c)(ii) (1 mark): The extract from the day 5 leaf was tested and the absorbance was found to be 0.04 au. Use the standard curve in Graph 1.3 to determine the protein concentratio
  45. June 2023, AS Component 1, Q1(c)(iii) (1 mark): Explain why chlorophyll would need to be removed from the extract before the absorbance is measured. [1]
  46. June 2023, AS Component 1, Q1(c)(iv) (1 mark): Explain why this method would not allow the determination of the actual acid phosphatase (ACP) concentration. [1]
  47. June 2023, AS Component 1, Q1(c)(v) (2 marks): Use evidence from Graph 1.3 to explain one possible source of error with the method used to produce the standard curve. [2]
  48. June 2022, Component 2, Q4(a)(i) (2 marks): Explain why nitrate and phosphate ions each need to be included in the solution used in the hydroponic system. [2]
  49. June 2022, Component 2, Q5(a)(i) (2 marks): Identify the type of reaction shown in image 5.1 and name two other bonds found in biological molecules that are formed by the same type of reaction. [2] Type o
  50. June 2022, Component 3, Q3(c)(ii) (2 marks): Describe how they could test the resulting liquid to show that no enzyme had left the column. Explain why this test is used. [2] The initial column used was 20
  51. June 2022, AS Component 1, Q1(a) (2 marks): Complete the table to name the groups shown in Image 1.1. [2] Group Name R NH2 COOH
  52. June 2022, AS Component 1, Q1(b) (1 mark): Apart from the elements shown in Image 1.1, state one other element which is found in some amino acids. [1]
  53. June 2022, AS Component 1, Q6 (9 marks): Lysozyme is an enzyme which catalyses the breakdown of glycosidic bonds in polysaccharides in bacterial cell walls. It works using the induced fit model of enzy
  54. June 2022, AS Component 2, Q1(c)(iv) (2 marks): Ions such as calcium and phosphate are absorbed into the blood in the ileum. State their roles as components of structures or biological molecules in the body.
  55. Autumn 2021, Component 1, Q2(a)(iii) (2 marks): Micro-organisms may be grown in the laboratory if supplied with suitable nutrients. Explain why micro-organisms must be provided with a source of: I. nitrogen
  56. Autumn 2021, Component 2, Q4(a)(i) (2 marks): One trans-membrane part of the protein, labelled T on image 4.1, is in the form of an alpha helix. State the level of protein structure present in an alpha heli
  57. Autumn 2021, Component 2, Q4(a)(ii) (2 marks): State whether the region of the protein labelled H on image 4.1 contains amino acids which are hydrophobic or hydrophilic. Explain your answer. [2] The presence
  58. Autumn 2021, Component 3, Q1(b)(i) (1 mark): Give the molecular formula of raffinose. [1]
  59. Autumn 2021, Component 3, Q1(c)(i) (2 marks): State two properties of starch that make it an effective storage molecule. [2] Image 1.3 shows starch grains in a plant cell. Image 1.3 Y X
  60. Autumn 2021, Component 3, Q1(c)(ii) (1 mark): Starch grains are normally transparent, but can be treated to become visible under the microscope. Suggest why these starch grains appear to be blue. [1]
  61. Autumn 2021, Component 3, Q1(d) (2 marks): Give two differences between a starch molecule and a cellulose molecule. [2]
  62. Autumn 2021, AS Component 1, Q1(a)(i) (2 marks): Explain why water is described as a polar molecule. [2]
  63. Autumn 2021, AS Component 1, Q1(a)(ii) (2 marks): Explain why water is described as a universal solvent. [2] Image 1.1 shows a typical pond. Image 1.1 pondweed pond skater fish
  64. Autumn 2021, AS Component 1, Q1(b)(i) (2 marks): The temperature of the pond stays relatively constant throughout the year. [2]
  65. Autumn 2021, AS Component 1, Q1(b)(ii) (2 marks): Fish and plants can survive when the pond freezes over. [2]
  66. Autumn 2021, AS Component 1, Q1(b)(iii) (2 marks): Pond skaters can live on the surface of the pond. [2]
  67. Autumn 2021, AS Component 1, Q1(b)(iv) (2 marks): Pondweed can grow underwater. [2]
  68. Autumn 2021, AS Component 1, Q3(a) (4 marks): Using image 3.1 and your knowledge of plant cell wall structure, identify four differences in the structure of bacterial and plant cell walls. [4] Bacterial cel
  69. Autumn 2021, AS Component 1, Q5(a)(i) (2 marks): Complete image 5.1 to show how the molecule would be broken down into two monosaccharides. [2]
  70. Autumn 2021, AS Component 1, Q5(a)(ii) (1 mark): Name the bond which is broken in the digestion of lactose. [1]
  71. Autumn 2021, AS Component 1, Q5(a)(iii) (1 mark): Explain why glucose and galactose are known as structural isomers of one another. [1] Milk may be treated to break down the lactose into its constituent monosac
  72. Autumn 2020, Component 1, Q1(b)(i) (1 mark): State one element, other than carbon, hydrogen and oxygen, that is found in the chlorophyll molecule. [1]
  73. Autumn 2020, Component 1, Q2(a)(i) (2 marks): RuBisCO shows all four levels of protein structure. Briefly describe what is meant by the following terms: [2] Primary structure Secondary structure Tertiary st
  74. Autumn 2020, Component 3, Q3(a)(i) (1 mark): Identify which of these chains would have a more negative effect on human health. Explain your answer. [1]
  75. Autumn 2020, Component 3, Q3(a)(ii) (1 mark): Explain why triglycerides are not regarded as polymers. [1] Lipase enzymes are released by the pancreas.
  76. Autumn 2020, Component 3, Q5(a)(ii) (3 marks): The fluid collected contains sucrose. Describe a chemical test that the scientist could use to confirm that it was sucrose present in the fluid collected from t
  77. Autumn 2020, AS Component 1, Q1(a)(i) (1 mark): Name the bonds in the triglyceride molecule which are hydrolysed by lipase enzymes. [1]
  78. Autumn 2020, AS Component 1, Q1(a)(ii) (1 mark): Following hydrolysis of these bonds, name the molecule that would be formed from portion B of the molecule in the diagram. [1]
  79. Autumn 2020, AS Component 1, Q1(a)(iii) (1 mark): Explain why it would be incorrect to refer to a triglyceride as a polymer. [1]
  80. Autumn 2020, AS Component 1, Q1(a)(iv) (2 marks): Describe a test which could be performed to detect the presence of triglyceride in a sample. [2]
  81. Autumn 2020, AS Component 1, Q1(a)(v) (2 marks): Identify the specific type of molecule shown in portion A of image 1.1. Explain your answer. [2]
  82. Autumn 2020, AS Component 1, Q1(a)(vi) (2 marks): Explain why a diet high in this type of molecule could increase the risk of heart disease. [2] Many seeds contain large amounts of lipid as a proportion of thei
  83. Autumn 2020, AS Component 1, Q1(b) (3 marks): With reference to the data in table 1.2 explain the advantage to plants of using lipid as a food reserve in their seeds as opposed to carbohydrate. [3]
  84. Autumn 2020, AS Component 1, Q3(c)(i) (2 marks): State the highest level of protein structure shown in image 3.2 and identify the bonds that maintain the structure. [2]
  85. Autumn 2020, AS Component 1, Q4(a)(i) (1 mark): Suggest the class of biological molecules to which the signal molecules belong. [1]
  86. June 2019, Component 1, Q3(d) (3 marks): Following the synthesis of carbohydrate, a number of inorganic ions are needed to synthesise other biological molecules. State three different biological molecu
  87. June 2019, AS Component 1, Q2(a) (1 mark): Explain why these molecules are termed structural isomers. [1] The –COOH group is found in several different biological molecules. Two of these molecules are sh
  88. June 2019, AS Component 1, Q2(b)(i) (1 mark): Name the type of molecules X and Y. [1] X Y
  89. June 2019, AS Component 1, Q2(b)(ii) (1 mark): State what is represented by –R in molecule X. [1] Molecule Y is found as a component of a group of molecules that are involved in energy storage and thermal in
  90. June 2019, AS Component 1, Q2(b)(iii) (3 marks): Name this group of molecules and describe how you would test for their presence in a sample of food. [3] Adipose tissue is found in mammals in two different for
  91. June 2019, AS Component 1, Q2(b)(iv) (2 marks): The diameter of the lipid vacuole in the white fat cell measured 80 µm. Calculate the volume of the lipid vacuole located in the white fat cell. Use the formula
  92. June 2019, AS Component 1, Q2(b)(v) (2 marks): Brown and white fat cells in seals help them survive in cold water. Using the information provided, suggest how the structure of each type of fat cell is an ada
  93. June 2019, AS Component 1, Q3(a)(i) (2 marks): If lactase is present, bond X is broken in this reaction. Name this type of bond and the type of reaction that breaks this bond. [2] Bond X Reaction
  94. June 2019, AS Component 1, Q3(a)(ii) (1 mark): Explain how you can identify that the isomer of glucose shown in the diagram above is β-glucose. [1]
  95. June 2019, AS Component 2, Q2(b) (2 marks): Name one inorganic ion the algae would require for growth and explain why it cannot grow without this inorganic ion. [2]
  96. June 2018, Component 1, Q4(b)(ii) (4 marks): Using the diagram opposite explain how the lack of the debranching enzyme causes low blood glucose. [4]
  97. June 2018, Component 1, Q4(e) (1 mark): How does glycogen differ structurally from the storage polysaccharide starch? [1]
  98. June 2018, Component 2, Q4(c)(ii) (3 marks): the use of nitrate fertiliser to increase grain size; [3]
  99. June 2018, Component 3, Q6(a)(i) (2 marks): Describe the biochemical breakdown of cellulose to release the respiratory substrates for the bacteria. [2]
  100. June 2018, AS Component 1, Q2(c)(ii) (1 mark): The molecule shown in the diagram is a part of a peptidoglycan molecule. Explain why a peptidoglycan cannot be classified as a true polysaccharide. [1]
  101. June 2018, AS Component 1, Q2(c)(iii) (1 mark): NAG and NAM can exist as alpha or beta isomers. State what is meant by an isomer. [1]
  102. June 2018, AS Component 1, Q2(c)(iv) (1 mark): Identify which isomers of NAG and NAM are found in this molecule. Explain your answer. [1]
  103. June 2018, AS Component 1, Q2(c)(v) (3 marks): In plant cells, cellulose carries out the same function as the peptidoglycan in bacterial cell walls. Peptidoglycan molecules can be cross-linked by the formati
  104. June 2018, AS Component 1, Q3(b) (2 marks): During translation amino acids can be joined together in different sequences. The drawings below show the structural formulae of the amino acids methionine and
  105. June 2018, AS Component 1, Q4(b)(i) (2 marks): Explain why water is a polar molecule. [2]
  106. June 2018, AS Component 1, Q4(c)(i) (2 marks): Describe one use made by a plant of the ions listed below: [2] Magnesium Nitrate
  107. June 2017, Component 1, Q2(a)(i) (2 marks): State why nitrogen and phosphorus are needed for plant growth. [2]
  108. June 2017, Component 1, Q2(a)(ii) (1 mark): Give an example of a biological molecule that contains sulfur. [1] Field trials were carried out by a fertiliser company to determine the effect of the four mac
  109. June 2017, Component 2, Q5(c)(i) (2 marks): 6% omega-3 fatty acids, so are useful for fish farm feed. (c) With reference to the diagrams, explain why these compounds are described as: (i) fatty acids; [2]
  110. June 2017, Component 2, Q5(c)(ii) (1 mark): polyunsaturated. [1]
  111. June 2017, Component 2, Q5(d)(i) (2 marks): These compounds are present in fish in the form of triglygerides or phospholipids. The diagram below shows some of the atoms of a glycerol molecule and a fatty
  112. June 2017, Component 2, Q5(d)(ii) (2 marks): Give one function for the following types of lipid in fish: [2] triglyceride; phospholipids.
  113. June 2017, Component 3, Q1(d)(i) (3 marks): The chitin in the walls of the tracheae has a similar chemical bonding and function as cellulose in plant cell walls. Explain how the chemical bonding in chitin
  114. June 2017, Component 3, Q4(a)(i) (3 marks): Describe a biochemical test that could demonstrate the presence of glucose in urine and explain why this test can only provide semi-quantitative results. [3]
  115. June 2017, AS Component 1, Q1(a)(i) (3 marks): Name this type of lipid and describe two uses of this type of molecule in organisms. [3] Type of lipid Uses
  116. June 2017, AS Component 1, Q1(a)(ii) (2 marks): Describe how you would test for the presence of lipid in a tissue extract. [2]
  117. June 2017, AS Component 1, Q1(a)(iii) (3 marks): Describe how components Y and Z in the lipid differ from component X and explain why it is recommended that humans eat a higher proportion of lipids containing
  118. June 2017, AS Component 1, Q5(a)(i) (1 mark): What is meant by the term hydrolysis? [1]
  119. June 2017, AS Component 1, Q6 (9 marks): Insulin is a protein composed of polypeptide chains A and B and is involved in the control of blood glucose levels. It binds to receptors in the cell membranes
  120. June 2016, AS Component 1, Q2(b) (2 marks): Describe the biochemical structure of a glycoprotein. [2] The initial stage of infection involves the following process. extra cellular fluid binding cell membr
  121. June 2016, AS Component 1, Q3(a)(i) (2 marks): When tested, a urine sample gave an absorbance of 0.17 a.u.. State and explain what diagnosis you could reach based on this reading. [2]
  122. June 2016, AS Component 1, Q3(a)(ii) (1 mark): Why is it not possible to use the standard curve for glucose determination in a whole blood sample? [1]
  123. June 2016, AS Component 1, Q3(c)(i) (1 mark): Describe the difference between these two molecules. [1]
  124. June 2016, AS Component 1, Q3(c)(ii) (1 mark): What would be the products of a condensation reaction between these two molecules? [1]
  125. June 2016, AS Component 1, Q5(a) (3 marks): Explain what caused the indicator to lose the pink colour and become colourless. [3]
  126. June 2016, AS Component 2, Q6(a)(i) (3 marks): With reference to the structure of starch and cellulose molecules, explain why α amylase is unable to digest cellulose even though starch and cellulose are both
  127. June 2016, AS Component 2, Q6(b)(i) (2 marks): Complete the table by giving the names of the reagents they should have used. [2] Food substance Reagent starch reducing sugar The results they obtained for red
  128. June 2016, AS Component 2, Q6(b)(ii) (1 mark): What conclusion could the students have drawn from these results? [1]

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