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Cells and microscopy: OCR A‑Level Biology B questions

Every OCR A-Level Biology B exam question on 2.1.1 Cells and microscopy, 2016–2025, with its mark scheme and examiner’s report.

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1,889 questions

  1. Q1

    June 2025 · Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 1, question 1: Which type of blood cell is shown in the annotated drawing? Non-granulated cytoplasm Kidney-bean shaped nucleus A Erythrocyte B Lymphocyte C Monocyte D Neutroph

  2. Q2

    June 2025 · Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 1, question 2: Which technique uses fluorescent markers to tag cells so they can be counted and identified when passed through a laser beam? A Differential staining B Flow cyt

  3. Q33(b)(ii)

    June 2025 · Paper 1

    4 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 1, question 33(b)(ii): The diagram below shows a type of cell that was extracted from the developing root nodule labelled in the photomicrograph. Cell wall Plasma membrane Cytoplasm D

  4. Q34(a)(ii)

    June 2025 · Paper 1

    2 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 1, question 34(a)(ii): The same myofibril has been labelled G on both micrographs. Calculate the actual diameter of myofibril G before spaceflight. Diameter = μm [2]

  5. Q1(a)(ii)

    June 2025 · Paper 3

    2 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 3, question 1(a)(ii): The diameter of one region of the root is represented by the line C in the image. The magnification used to produce the image was × 20. Calculate the actual dia

  6. Q3(a)

    June 2025 · Paper 3

    2 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 3, question 3(a): State two ways in which the student could improve their drawing. 1 2 [2]

  7. Q3(b)

    June 2025 · Paper 3

    3 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 Paper 3, question 3(b): The student concludes that ‘although it does not seem to have mitochondria, P. myojinensis is more similar to a eukaryote than a prokaryote’. Discuss the eviden

  8. Q3

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 3: The transmission electron micrograph shows the ultrastructure of a mammalian cell. P Which option describes the function of the structure labelled P? A It produ

  9. Q4

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 4: A student observed a blood sample using a light microscope with a calibrated eyepiece graticule. They measured the diameter of a lymphocyte and calculated its a

  10. Q13

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 13: Which molecule is found in the cell wall of a bacterium? A Cellulose B Lignin C Peptidoglycan D Phospholipid Your answer [1]

  11. Q24(b)(ii)

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 24(b)(ii): Suggest the mechanism of transport across cell surface membranes that involves dynamin. [1] 20 In a recent study into the role of dynamin in the infection of ho

  12. Q25(a)(i)

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(a)(i): Suggest one reason why steps 1 and 2 are included in the method. [1]

  13. Q25(a)(ii)

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(a)(ii): Suggest one reason why it is necessary to mix the sample again thoroughly in step 4. [1]

  14. Q25(a)(iii)

    June 2025 · AS Paper 1

    3 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(a)(iii): Outline further steps in the method that would enable the students to estimate the number of individual algae present in the sample. [3]

  15. Q25(b)(i)

    June 2025 · AS Paper 1

    1 mark2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(b)(i): Using the image, explain a disadvantage of using a haemocytometer to estimate the number of algal cells in a pond water sample. [1]

  16. Q25(b)(ii)

    June 2025 · AS Paper 1

    2 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(b)(ii): The diameter of individual P of the algal species, Pandorina morum, is shown on the image. Calculate the actual diameter of this individual. Diameter = μm [2]

  17. Q25(b)(iii)

    June 2025 · AS Paper 1

    3 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(b)(iii): Wet biomass (biovolume) of P. morum in the sample can be calculated using the equation: Biovolume = number of individuals per cm3 × mean volume of individuals T

  18. Q25(c)

    June 2025 · AS Paper 1

    2 marks2.1.1 Cells and microscopy
    The whole paper ↗
    June 2025 AS Paper 1, question 25(c): The diagram shows the ultrastructure of an algal cell from the Euglena species. R S U T Give the letters identifying one organelle that would be present and one

  19. Q1(b)

    June 2025 · AS Paper 2

    2 marks2.1.1 Cells and microscopy
    No published mark scheme
    The whole paper ↗
    June 2025 AS Paper 2, question 1(b): The image below shows a section through the wall of an artery. X Y ×500 Calculate the actual width of the artery wall between points X and Y. Give your answer t

  20. Q6(a)(i)

    June 2025 · AS Paper 2

    2 marks2.1.1 Cells and microscopy
    No published mark scheme
    The whole paper ↗
    June 2025 AS Paper 2, question 6(a)(i): State the type of microscope used to produce this image. Give a reason for your answer. Type Reason [2]
All 139 questions on Cells and microscopy, as a list
  1. June 2025, Paper 1, Q1 (1 mark): Which type of blood cell is shown in the annotated drawing? Non-granulated cytoplasm Kidney-bean shaped nucleus A Erythrocyte B Lymphocyte C Monocyte D Neutroph
  2. June 2025, Paper 1, Q2 (1 mark): Which technique uses fluorescent markers to tag cells so they can be counted and identified when passed through a laser beam? A Differential staining B Flow cyt
  3. June 2025, Paper 1, Q33(b)(ii) (4 marks): The diagram below shows a type of cell that was extracted from the developing root nodule labelled in the photomicrograph. Cell wall Plasma membrane Cytoplasm D
  4. June 2025, Paper 1, Q34(a)(ii) (2 marks): The same myofibril has been labelled G on both micrographs. Calculate the actual diameter of myofibril G before spaceflight. Diameter = μm [2]
  5. June 2025, Paper 3, Q1(a)(ii) (2 marks): The diameter of one region of the root is represented by the line C in the image. The magnification used to produce the image was × 20. Calculate the actual dia
  6. June 2025, Paper 3, Q3(a) (2 marks): State two ways in which the student could improve their drawing. 1 2 [2]
  7. June 2025, Paper 3, Q3(b) (3 marks): The student concludes that ‘although it does not seem to have mitochondria, P. myojinensis is more similar to a eukaryote than a prokaryote’. Discuss the eviden
  8. June 2025, AS Paper 1, Q3 (1 mark): The transmission electron micrograph shows the ultrastructure of a mammalian cell. P Which option describes the function of the structure labelled P? A It produ
  9. June 2025, AS Paper 1, Q4 (1 mark): A student observed a blood sample using a light microscope with a calibrated eyepiece graticule. They measured the diameter of a lymphocyte and calculated its a
  10. June 2025, AS Paper 1, Q13 (1 mark): Which molecule is found in the cell wall of a bacterium? A Cellulose B Lignin C Peptidoglycan D Phospholipid Your answer [1]
  11. June 2025, AS Paper 1, Q24(b)(ii) (1 mark): Suggest the mechanism of transport across cell surface membranes that involves dynamin. [1] 20 In a recent study into the role of dynamin in the infection of ho
  12. June 2025, AS Paper 1, Q25(a)(i) (1 mark): Suggest one reason why steps 1 and 2 are included in the method. [1]
  13. June 2025, AS Paper 1, Q25(a)(ii) (1 mark): Suggest one reason why it is necessary to mix the sample again thoroughly in step 4. [1]
  14. June 2025, AS Paper 1, Q25(a)(iii) (3 marks): Outline further steps in the method that would enable the students to estimate the number of individual algae present in the sample. [3]
  15. June 2025, AS Paper 1, Q25(b)(i) (1 mark): Using the image, explain a disadvantage of using a haemocytometer to estimate the number of algal cells in a pond water sample. [1]
  16. June 2025, AS Paper 1, Q25(b)(ii) (2 marks): The diameter of individual P of the algal species, Pandorina morum, is shown on the image. Calculate the actual diameter of this individual. Diameter = μm [2]
  17. June 2025, AS Paper 1, Q25(b)(iii) (3 marks): Wet biomass (biovolume) of P. morum in the sample can be calculated using the equation: Biovolume = number of individuals per cm3 × mean volume of individuals T
  18. June 2025, AS Paper 1, Q25(c) (2 marks): The diagram shows the ultrastructure of an algal cell from the Euglena species. R S U T Give the letters identifying one organelle that would be present and one
  19. June 2025, AS Paper 2, Q1(b) (2 marks): The image below shows a section through the wall of an artery. X Y ×500 Calculate the actual width of the artery wall between points X and Y. Give your answer t
  20. June 2025, AS Paper 2, Q6(a)(i) (2 marks): State the type of microscope used to produce this image. Give a reason for your answer. Type Reason [2]
  21. June 2024, Paper 1, Q2 (1 mark): Which of the options identifies the leucocyte in the electron micrograph? A Lymphocyte B Macrophage C Monocyte D Neutrophil Your answer [1]
  22. June 2024, Paper 1, Q3 (1 mark): What is the role of the organelle labelled L? A Aerobic respiration B Lipid synthesis C Protein synthesis D Transport Your answer [1]
  23. June 2024, Paper 1, Q34(a)(ii) (2 marks): Calculate the actual length of Q between points X and Y. Actual length = μ m [2]
  24. June 2024, Paper 3, Q3(c) (1 mark): Hypothyroidism can affect the concentration of red blood cells in a person’s blood. State a method that could be used to measure the concentration of red blood
  25. June 2024, AS Paper 1, Q21(c)(i) (2 marks): Suggest a type of microscope used to produce the photomicrograph in Fig. 21.2 and give a reason for your choice. Type of microscope Reason [2]
  26. June 2024, AS Paper 1, Q21(c)(ii) (2 marks): Calculate the actual length of the 1 cm scale bar shown on Fig. 21.2 and give appropriate units. Actual length = Units = [2]
  27. June 2024, AS Paper 1, Q23(a)(i) (1 mark): Suggest why a buffer was used in this investigation. [1]
  28. June 2024, AS Paper 1, Q23(a)(ii) (1 mark): Suggest one reason why the scientists waited 200 s before adding the chloroplast solution. [1]
  29. June 2024, AS Paper 1, Q23(b)(i) (3 marks): Use the grid to plot an appropriate graph for these data. [3]
  30. June 2024, AS Paper 1, Q23(b)(ii) (2 marks): Use your graph to calculate the rate of uptake of CO2 at 275 s. Give your answer in standard form. Rate of uptake of CO2 = μmol dm–3 s–1 [2]
  31. June 2024, AS Paper 1, Q23(b)(iii) (3 marks): Use your graph to suggest a mechanism of transport for CO2 across the membrane and comment on the permeability of chloroplast membranes to CO2. [3]
  32. June 2024, AS Paper 2, Q1(a)(iii) (2 marks): Calculate the actual length of the structure between X–Y. Actual length = μm [2]
  33. June 2024, AS Paper 2, Q2(b)(i) (2 marks): Using your knowledge of transport of molecules across membranes, explain the shape of the curve at region A and at region B. Region A Region B [2]
  34. June 2024, AS Paper 2, Q2(b)(ii) (1 mark): Cells in the salivary glands require oxygen for aerobic respiration. Draw a line on the graph to show the rate of uptake of oxygen by the cells of the salivary
  35. June 2024, AS Paper 2, Q2(c) (6 marks): Amino acids have the same general structure with four different chemical groups attached to a central carbon atom. The structure of the amino acid valine is sho
  36. June 2024, AS Paper 2, Q5(d)(ii) (2 marks): Cytotoxin has both polar and non-polar regions. Suggest how cytotoxin binds to the membrane and causes damage to the blood cells. [2]
  37. June 2023, Paper 1, Q2 (1 mark): The diagram shows substance X being transported across a cell membrane. Substance X 2 1 Which transport mechanism is being used to transport substance X? A Acti
  38. June 2023, Paper 1, Q36(a)(i) (2 marks): Outline a correct method for counting cells using a haemocytometer. [2]
  39. June 2023, Paper 1, Q36(a)(ii) (2 marks): Explain how the class results would be affected by including the results obtained by the student who counted all the cells in their field of view. [2]
  40. June 2023, Paper 1, Q36(b) (3 marks): Other methods can be used to count cells. Complete the sentences about a method to count cells using the most appropriate word(s). is an electronic method of co
  41. June 2023, Paper 2, Q3(a)(i) (1 mark): State the letter on Fig. 3.1 that identifies the component of the membrane that binds to LPS. [1]
  42. June 2023, Paper 2, Q3(a)(ii) (2 marks): Explain why the membrane is described as a fluid mosaic. [2]
  43. June 2023, Paper 2, Q7(c) (4 marks): Lung surfactant is a mixture of phospholipids and proteins that helps the alveoli stretch and expand during breathing in and prevents them collapsing when breat
  44. June 2023, Paper 3, Q1(a)(ii) (2 marks): The magnification used to produce the TEM in Fig. 1.1 was × 20 000. Calculate the actual diameter of the structure labelled D in Fig. 1.1. Give your answer in s
  45. June 2023, Paper 3, Q4(d)(ii) (6 marks): The domestic rabbit, Oryctolagus cuniculus domesticus, is a subspecies of European rabbit. It is a popular pet and has been selectively bred for fur colour and
  46. June 2022, Paper 1, Q11 (1 mark): Flow cytometry can be used to determine the concentration of bacterial cells in a sample by comparing fluorescently-stained bacterial cells with a known concent
  47. June 2022, Paper 1, Q31(c)(ii) (2 marks): Daptomycin has a bactericidal effect on gram positive bacteria by causing cytosol to leak out of bacterial cells. Using the information in Fig. 31.2, suggest ho
  48. June 2022, Paper 1, Q35(a)(i) (1 mark): Name the type of leucocyte shown. [1]
  49. June 2022, Paper 1, Q35(a)(ii) (2 marks): Make an annotated drawing of the leucocyte. [2] 35 The eyepiece graticule used was calibrated as shown in the diagram. 100 μm 0 10 20 30 40 50 60 70 80 90100 Ey
  50. June 2022, Paper 1, Q35(a)(iii) (1 mark): Name the apparatus used to calibrate the eyepiece graticule. [1]
  51. June 2022, Paper 1, Q35(a)(iv) (2 marks): Calculate the diameter of the leucocyte. Give your answer to 2 significant figures. Diameter = µm [2]
  52. June 2022, Paper 3, Q1(a)(iii) (2 marks): The diameter of one region of pancreatic tissue is represented by the line Z. Calculate the actual diameter of the region labelled Z. Give your answer in µm and
  53. June 2022, Paper 3, Q1(a)(iv) (2 marks): A stage micrometer can be used when measuring the linear dimensions of cells, such as those of the pancreatic tissue, viewed under a light microscope. Outline h
  54. June 2022, AS Paper 1, Q25(a) (2 marks): Identify the blood cells in Fig. 25 and complete the table below. Name Letter Erythrocyte Monocyte Lymphocyte [2]
  55. June 2022, AS Paper 1, Q25(b)(i) (1 mark): Give one reason why it was important to make a correct smear (film) of the blood sample. [1]
  56. June 2022, AS Paper 1, Q25(b)(ii) (1 mark): Give one reason why Leishman’s stain was used. [1]
  57. June 2022, AS Paper 1, Q25(b)(iii) (1 mark): Suggest why macrophages were not present in this blood sample. [1]
  58. June 2022, AS Paper 2, Q6(a)(i) (1 mark): Draw a box on Fig. 6.1 around the region of the phospholipid that is glycerol. [1]
  59. June 2022, AS Paper 2, Q6(a)(ii) (1 mark): Label A in Fig. 6.1 shows a double bond between carbons. Describe the effect this double bond between carbons has on the properties of this molecule. [1]
  60. June 2022, AS Paper 2, Q6(b)(i) (2 marks): Explain why the cell surface membrane of an intestinal epithelial cell contains cholesterol but the mitochondrial membrane does not. [2]
  61. June 2022, AS Paper 2, Q6(b)(ii) (1 mark): Counting the number of each type of lipid molecule would be too difficult to do accurately. Suggest one other reason why calculating the percentage mass of the
  62. June 2022, AS Paper 2, Q6(c) (4 marks): The rate of active transport of a molecule across a membrane is dependent on a number of different factors. State and explain two factors that can increase the
  63. November 2021, Paper 1, Q8 (1 mark): Milk fat contains many different types of triglycerides. The molecules that make up these triglycerides can affect the flavour and nutritional properties of mil
  64. November 2021, Paper 1, Q14 (1 mark): An investigation was carried out into the effect of concentration of a substance on its rate of uptake into cells. The cells were placed in solutions of the sub
  65. November 2021, Paper 1, Q15 (1 mark): Which of the eukaryotic cell membranes, A to D, is used to isolate enzymes that could cause cellular damage? A lysosome membrane B mitochondrial membrane C nucl
  66. November 2021, Paper 1, Q32(a) (2 marks): The tissues of the eye shown in the photomicrograph were stained using eosin, which binds to cytoplasmic proteins staining them pink, and haematoxylin, which st
  67. November 2021, Paper 1, Q32(c)(i) (2 marks): Find the mean of the data and use it to calculate the actual width of the retinal layer. Width = μm [2]
  68. November 2021, Paper 1, Q32(c)(ii) (2 marks): Calculate the uncertainty in the mean value for this data. Use the equation: R 2√N R = difference between maximum and minimum values N = number of measurements
  69. November 2021, Paper 3, Q3(b) (2 marks): Fig. 3.2 is a photomicrograph of the lower surface of a leaf showing stomata as viewed using a light microscope. P ×1200 Fig. 3.2 Calculate the actual length of
  70. November 2021, AS Paper 1, Q1 (1 mark): A student used a haemocytometer to count the number of yeast cells in a diluted sample. The North-West counting rule was applied by the student when counting th
  71. November 2021, AS Paper 1, Q18 (1 mark): Researchers used radioactively labelled amino acids to track the movement of proteins through a The graph below shows the percentage of radioactively labelled p
  72. November 2021, AS Paper 2, Q1(a)(ii) (2 marks): Calculate the magnification of the image in Fig. 1.1. Magnification = [2]
  73. November 2021, AS Paper 2, Q1(d) (6 marks): Fig. 1.1 is a photomicrograph showing some of the cells that line the bronchus. X 4 μm Fig. 1.1 (d)* Eosinophils are a type of white blood cell involved in prod
  74. November 2021, AS Paper 2, Q6(a) (2 marks): Describe two structural differences between an erythrocyte and a prokaryotic cell such as M. tuberculosis. Difference 1 Difference 2 [2] Question 6(b) begins on
  75. November 2021, AS Paper 2, Q6(b) (3 marks): Flow cytometry is a technique used to detect and measure the physical characteristics of blood cells and platelets. The graph shows the analysis of a blood samp
  76. November 2020, Paper 1, Q2 (1 mark): Which of the molecules, A to D, reduces the permeability of the plasma membrane to most substances? A carbohydrate B cholesterol C glycoprotein D protein Your a
  77. November 2020, Paper 1, Q3 (1 mark): To which of the substances, A to D, is the plasma membrane of an axon least permeable? A ATP B glucose K+ C Na+ D Your answer [1]
  78. November 2020, Paper 1, Q7 (1 mark): Which of the cell organelles, A to D, is most likely to increase the mass of a newly-translated protein? A Golgi apparatus B lysosome C nucleus D smooth endopla
  79. November 2020, Paper 2, Q4(a)(i) (3 marks): Identify the three different types of leucocytes labelled A, B and C on Fig. 4. A B C [3]
  80. November 2020, Paper 2, Q4(a)(ii) (1 mark): State one structural feature of the cell labelled D in Fig. 4 that is different to other eukaryotic cells. [1]
  81. November 2020, Paper 2, Q4(b)(i) (1 mark): Suggest one thing you would do when diluting the blood sample to ensure that the number of erythrocytes is calculated accurately. [1]
  82. November 2020, Paper 2, Q4(b)(ii) (4 marks): Calculate the total concentration of erythrocytes in the undiluted blood sample. Give your answer as cells cm−3 in standard form. concentration = cells cm−3 [4]
  83. November 2020, Paper 3, Q3(a)(i) (2 marks): Calculate the actual height of the cone cell using line X. Give your answer to 3 significant figures. height of cone cell = µm [2]
  84. November 2020, Paper 3, Q3(a)(iii) (2 marks): Give two disadvantages of the technique used to prepare the image in Fig. 3.1. [2]
  85. November 2020, Paper 3, Q4(b) (1 mark): Fig. 4.2 shows a light micrograph and Fig. 4.3 shows a scanning electron micrograph of nerve cells in the human brain. Fig. 4.2 Fig. 4.3 The images in Fig. 4.2
  86. November 2020, AS Paper 1, Q1 (1 mark): Which of the following cell structures, A to D, are present in prokaryotic cells? A lysosomes B vacuoles C ribosomes D starch grains Your answer [1]
  87. November 2020, AS Paper 1, Q2 (1 mark): A student observed a stained blood smear using a light microscope and wrote the following description about one of the blood cells: • large cell • nucleus with
  88. November 2020, AS Paper 1, Q3 (1 mark): The diagram shows an eyepiece graticule and stage micrometer used to measure the length of a mitochondrion. 0.1 mm 0 10 20 30 40 50 60 70 80 90 100 The mitochon
  89. November 2020, AS Paper 1, Q21(d)(ii) (3 marks): Calculate the actual length of stoma X. Give your answer to 2 significant figures. length = unit [3] for the next question
  90. June 2019, Paper 1, Q1 (1 mark): Which of the options, A to D, is a property of the phosphate group in phospholipids? A hydrophilic B hydrophobic C non-polar D saturated Your answer [1]
  91. June 2019, Paper 1, Q12 (1 mark): Which of the biological processes, A to D, is an example of facilitated diffusion? A influx of sodium ions into a neurone during an action potential B loading o
  92. June 2019, Paper 1, Q27 (1 mark): The diagram below shows the ultrastructure of an animal cell. Four structures are labelled W to Z. W X Z Y Which of the rows in the table below correctly identi
  93. June 2019, Paper 1, Q33(b) (2 marks): Osmosis can also be investigated on a single-cell scale with microscopy by measuring cell size. Fig. 33 shows the view down a microscope fitted with a stage mic
  94. June 2019, Paper 2, Q1(b) (4 marks): The article describes the use of flow cytometry (‘automated blood analysers’) to identify genetic variants linked to the risk of developing multiple myeloma. Ex
  95. June 2019, Paper 3, Q4(d)(ii) (4 marks): The group Eukaryota includes both animal and plant species. There are similarities and differences in the ultrastructure of cells found in animal and plant spec
  96. June 2019, AS Paper 1, Q1 (1 mark): The diagram below shows a cell found in the bloodstream of a mammal. X nucleus Which of the statements, A to D, correctly identifies the cell and structure X? A
  97. June 2019, AS Paper 1, Q2 (1 mark): A scientist was observing electron micrographs of eukaryotic cells and writing descriptions for the organelles observed. One of the organelles was described as:
  98. June 2019, AS Paper 1, Q3 (1 mark): Haladaptatus cibarius is a photosynthetic organism found in salt lakes. The cells of H. cibarius do not have nuclei or membrane-bound organelles. Which of the o
  99. June 2019, AS Paper 1, Q4 (1 mark): The diagram below shows the transport of solute Q through a cell surface membrane. Q Which of the statements, A to D, describes the transport of solute Q? A Sol
  100. June 2019, AS Paper 1, Q21(d)(ii) (2 marks): Suggest why the roots of A. rubrum seedlings in zone C had reduced uptake of nutrients during the investigation. [2]
  101. June 2019, AS Paper 1, Q24(b)(i) (2 marks): Describe how the sputum sample in Fig. 24 could have been prepared for viewing the cells of A. fumigatus using a light microscope. [2]
  102. June 2019, AS Paper 1, Q24(b)(ii) (2 marks): Calculate the magnification of the photomicrograph shown in Fig. 24. magnification = [2]
  103. June 2019, AS Paper 1, Q24(c) (4 marks): A. fumigatus can also be observed using other types of microscope such as scanning electron microscopes and transmission electron microscopes. The table below l
  104. June 2019, AS Paper 2, Q4(b) (2 marks): A high consumption of alcohol during pregnancy may lead to birth defects in the developing fetus, but it can also result in the formation of ulcers in the small
  105. June 2018, Paper 1, Q4 (1 mark): The diameter of cell X in the image is 15.5 mm and its actual diameter is 12.4 µm. Which of the options, A to D, is the magnification of the image? A ×125 B ×80
  106. June 2018, Paper 1, Q5 (1 mark): Which of the rows, A to D, in the table below correctly identifies cells X, Y and Z? Monocyte Neutrophil Lymphocyte A X Y Z B Z X Y C Y X Z D Y Z X Your answer
  107. June 2018, Paper 3, Q3(b)(i) (2 marks): The artery in Fig. 3.1 has a diameter of 0.40 mm measured between A and B. Calculate the magnification of this image. Show your working. Answer = [2]
  108. June 2018, AS Paper 1, Q3 (1 mark): A student was using an eyepiece graticule and a stage micrometer to calculate the length of a human cheek epithelial cell. The following calibration and measure
  109. June 2018, AS Paper 1, Q23(d)(i) (2 marks): The actual length of the bacterium shown in Fig. 23.3 between points M and N is 4 μm. Calculate the magnification of the micrograph. Give your answer to three s
  110. June 2018, AS Paper 2, Q6(a)(i) (2 marks): Name cells G and H in Fig. 6. G H [2]
  111. June 2018, AS Paper 2, Q6(a)(ii) (2 marks): The magnification of the image in Fig. 6 is ×500. Calculate the length represented by the scale bar labelled F. [2]
  112. June 2018, AS Paper 2, Q6(b)(i) (2 marks): Give one stage that is missing from the notes and explain the effect this would have on the resulting blood smear. [2]
  113. June 2018, AS Paper 2, Q6(b)(ii) (2 marks): Leishman’s stain mentioned in the notes is a differential stain. Explain why a differential stain is used when producing a blood smear. [2]
  114. June 2018, AS Paper 2, Q6(c) (3 marks): Flow cytometry is another technique used by pathologists for analysing blood samples. Describe the usefulness of flow cytometry for analysing blood samples. [3]
  115. June 2017, Paper 1, Q1 (1 mark): The diagram below represents a microscopic view of a haemocytometer. A triple-ruled square is further divided into 16 smaller squares. Which of the options, A t
  116. June 2017, Paper 1, Q5 (1 mark): A magnified section of a human blood smear is shown in the light micrograph below. The diameter of cell X in this image is 11 mm. X Magnification x750 Which of
  117. June 2017, Paper 2, Q7(a)(i) (5 marks): Identify the structures labelled D to H in Fig. 7.1. D E F G H [5]
  118. June 2017, Paper 2, Q7(a)(ii) (3 marks): Describe two functions of structure H and one function of structure J. H H J [3]
  119. June 2017, Paper 2, Q7(b)(i) (6 marks): Using Fig. 7.2 and your knowledge of the synthesis and secretion of proteins, identify the organelles corresponding to curves K, L and M on Fig. 7.2. Give reaso
  120. June 2017, Paper 2, Q7(b)(ii) (1 mark): Using Fig. 7.2, estimate the time taken for secretion of VSVG-GFP to reach a maximum. [1]
  121. June 2017, Paper 2, Q7(c) (2 marks): Vinblastine is a drug used in the treatment of cancer. It inhibits the assembly of microtubules. Another experiment similar to that described in part (b) was ca
  122. June 2017, AS Paper 1, Q1 (1 mark): The diagram below shows the structure of a cell surface (plasma) membrane. C B A D Which of the components, labelled A to D, regulates the fluidity of the membr
  123. June 2017, AS Paper 1, Q11 (1 mark): Flow cytometry can be used to distinguish types of leucocyte depending on the size of the cell and the granularity of the cytoplasm. The diagram below shows the
  124. June 2017, AS Paper 1, Q22(a) (1 mark): Name the membrane that surrounds the vacuole in plant cells. [1]
  125. June 2017, AS Paper 1, Q22(b)(i) (2 marks): During this investigation, the same volume of solution was used in each test tube. State two other variables that must also be controlled in this investigation
  126. June 2017, AS Paper 1, Q22(b)(ii) (4 marks): The students used their data to plot an appropriate graph, shown in Fig. 22. 0.6 0.4 absorbance 0.2 0 0 5 10 15 pH of solution Fig. 22 The students were told th
  127. June 2017, AS Paper 1, Q22(c) (2 marks): Betanin is soluble in water. Explain how the properties of the membrane surrounding the vacuole ensure that betanin does not leak out into the cytoplasm of heal
  128. June 2017, AS Paper 2, Q1(a) (3 marks): Using Fig. 1.1, complete the table below with the letter of the organelle that corresponds to the function being described. Function Letter Provides ATP Modifie
  129. June 2017, AS Paper 2, Q5(a)(i) (2 marks): Using Fig. 5.1, calculate the number of cells in 1 mm3 of undiluted blood. Answer = [2]
  130. June 2017, AS Paper 2, Q5(a)(ii) (4 marks): When preparing blood samples for counting different types of cell using a haemocytometer, technicians follow a set procedure. For each of the steps below, give
  131. June 2017, AS Paper 2, Q5(b) (4 marks): Using the information in Table 5 and Fig. 5.2, discuss any conclusions the technician could make about the health of this patient and whether a diagnosis could
  132. June 2016, AS Paper 1, Q6 (1 mark): Oxygen molecules enter cells by passive diffusion through the plasma (cell surface) membrane. The rate of diffusion of oxygen is affected by its concentration g
  133. June 2016, AS Paper 1, Q16 (1 mark): B-lymphocytes produce antibodies. The following organelles are involved in the synthesis and secretion of antibodies: 1. Golgi apparatus 2. ribosome 3. endoplas
  134. June 2016, AS Paper 1, Q19 (1 mark): Chlamydomonas is a small, fresh-water protoctist commonly found in ponds. A group of students collected a sample of pond water and counted the number of Chlamyd
  135. June 2016, AS Paper 1, Q23(a)(ii) (2 marks): Explain how the production and release of extracellular proteins in mammalian cells would differ from that of p60 in L. monocytogenes. [2]
  136. June 2016, AS Paper 2, Q1(a) (3 marks): The ultrastructure of plant cells has similarities and differences when compared to animal cells. Fig. 1.1 shows an electron micrograph of a cell from a dicotyl
  137. June 2016, AS Paper 2, Q1(b)(i) (2 marks): A light microscope was used to observe cells in the lower epidermis of a dicotyledonous leaf. Fig. 1.2, in the insert, shows a stage micrometer and an eyepiece
  138. June 2016, AS Paper 2, Q1(b)(ii) (2 marks): Fig. 1.3, in the insert, shows a stoma, guard cells and epidermal cells in the lower epidermis, as seen with a light microscope. The magnification is the same a
  139. June 2016, AS Paper 2, Q2(d) (6 marks): A group of students were investigating the protein content of a sports drink used by athletes. (d)* Proteases in the small intestine of an athlete will break do

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