1 The diagram shows a root hair cell from a lemon tree and some soil particles. root hair cell air spaces soil particle (a) (i) State one feature, visible in the diagram, which shows that a root hair cell is a plant cell. … [1] (ii) Describe how mineral ions pass from the soil into the root hair cell. … … … … … … [4] (b) The lemon tree has grown in the same soil for many years so the soil now lacks magnesium. Describe and explain the effect on the lemon tree of a lack of magnesium. … … … [2] [Total: 7]

1(a)(i) cell wall or large / central / sap + vacuole ; 1 1(a)(ii) any four from: dissolved in water ; through the cell wall ; carriers in membrane ; through the cell / partially permeable AW + membrane ; by active transport / diffusion ; correct reference to concentration gradient ; using energy (for active transport) ; from (aerobic) respiration (for active transport) ; 4 1(b) yellowing / chlorosis / reduced growth / cannot photosynthesise / make glucose / starch / sugar / carbohydrate ; deficiency of chlorophyll ; 2

1 The tissue of a peeled potato tuber is composed of many similar cells. You are going to investigate the effect of varying concentrations of sucrose solution on some potato tissue. You are provided with some potato tissue, distilled water (A) and three sucrose solutions (B, C and D). Solutions B, C and D are different concentrations of sucrose solution. • Label four test-tubes A, B, C and D. • Cut four strips from the potato each measuring 5 mm × 5 mm in cross-section and 80 mm long. This is their starting length, which must be identical for each strip. • Place one strip in each of the four test-tubes. • Add solution A to the test-tube labelled A so that it covers the potato strip. • Do the same for test-tube B with solution B, test-tube C with solution C and test-tube D with solution D. (a) (i) Record the time. … • Leave the potato strips in the solutions for 25–35 minutes. Continue with Questions 1(b) and 2 while you are waiting. • After the strips have been in solutions A, B, C and D for 25–35 minutes, pour away the solutions. Remove the strips and place them on a white tile, making sure that you can identify each strip. Record the time. time strips were removed from solutions … Calculate how long the strips had been left in the solutions, to the nearest minute. total time that strips were left in the solutions … minutes [2] (ii) Describe what you did to make sure that, when you removed the strips from the test- tubes, you knew which potato strip had been in which solution. … … [1] (iii) Measure the lengths of strips A, B, C and D. Record the lengths of each strip at the start and end of the investigation and calculate the changes in length. Enter your results in the table. solution start length / mm end length / mm change in length / mm flexibility of strip A B C D [5] (iv) Gently bend each strip to see how flexible it is. The more easily it bends, the more flexible it is. Decide the order of decreasing flexibility and use the scale to record this in the table. Record the most flexible strip as ++++ and the least flexible as +. most flexible/bendable ++++ +++ ++ least flexible/bendable + [2] (v) Describe and explain the changes in length and flexibility in the potato strip that had been in solution A. … … … … … … … … [3] (vi) Identify two problems with the method used in this investigation that might have led to unreliable conclusions. Suggest a way in which each could have been improved to make the results more reliable. problem 1 … improvement 1 … … problem 2 … improvement 2 … … [4] (b) Another student investigated the effect of varying concentrations of sucrose solution on some potato tissue by measuring changes in the mass of the tissue. He placed five pieces of potato tissue, each with a mass of 5 g, in five separate test-tubes. The test-tubes contained either distilled water or one of four concentrations of sucrose solution. Later he poured away the solutions. (i) State two factors, apart from the mass of tissue, that should have been kept constant when using this method. 1 … 2 … [2] When he removed the pieces of tissue from the test-tubes, he carefully dried them on a paper towel. (ii) Explain why it was important to dry them. … … … … [2] The table shows the measurements at the end of the investigation. sucrose concentration / mol per dm3 mass at end of investigation / g 0.0 5.7 0.2 5.2 0.4 4.6 0.5 4.3 0.8 3.3 (iii) Construct a line graph of the data in the table on the grid below. Join your points with ruled, straight lines. [4] (iv) Use your graph to determine the concentration of sucrose which will produce no change in mass. concentration … [2] (v) Describe the method you used to determine this concentration of sucrose. … … … [1] [Total: 28]

1(a)(i) start and end times recorded ; between 25–35 minutes + agrees with times given ; 2 1(a)(ii) labelled tile / surface they were placed on ; place in labelled container ; 1 1(a)(iii) all start lengths entered + all 80 ; all end lengths recorded ; A length > C length ; B and D lengths between A and C ; 5 change in length all correctly calculated and with ±to indicate gain or loss ; 1(a)(iv) all flexibilities recorded using symbols from key ; A least flexible + C most flexible ; 2 1(a)(v) strip longer ; less / least flexible ; water moved in / correct reference to osmosis ; cells larger / more turgid or increase in turgor pressure ; 3 1(a)(vi) problem improvement difficult to cut correct sizes / make small measurements ; use corer / chipper / use sharper or finer blade ; not much change in lengths ; more time / longer strips ; only one strip assessed / experiment only done once ; use more strips / repeat + calculate mean ; flexibility subjective / difficult to assess ; hang masses on strip / leave for longer ; time in solutions different ; time each strip separately ; potato strips floated ; not fully immersed in solution AW / weigh down potato strips ; 4 1(b)(i) temperature ; volume of solutions ; time + investigation / pieces of potato in solution ; same potato / variety of potato ; surface area (of potato) ; 2 1(b)(ii) remove excess / surface water or solution ; only mass of potato tissue weighed ; 2 1(b)(iii) sucrose on x-axis + fully labelled with units ; linear scales + origin labelled + good use of grid ; all points plotted correctly ; straight lines connecting plotted points + touching each point ; 4 1(b)(iv) 0.27 ± 0.01 ; mol per dm3 ; 2 1(b)(v) reference to original mass of 5 g as point to interpolate line from y- axis AW ; 1

2 The photograph shows the surface of a mammalian organ. B C A (a) (i) Identify this organ … [1] (ii) Name the structures labelled A … [1] (b) In the space below, make a large drawing of this organ as it appears in the photograph. [5] (c) (i) On the photograph, draw a line between B and C. Measure and record this length. … mm [2] (ii) On your drawing, draw a line at the same location as the line B–C. Measure and record the length of this line. … mm [2] (iii) Use your measurements in (c)(i) and (c)(ii) to calculate the magnification of your drawing compared to the photograph. Give your answer to one decimal place. Space for working. magnification × … [2] [Total: 13]

1(a)(i) 1 attempt to construct a two column / row table with ruled lines ; 2 header for seedling column + 1–6 ; 3 header for height column / row + mm ; 4 six measurements recorded ; 5 correct mean height calculated + mm ; 5 1(a)(ii) difficult to identify which part to measure, i.e. where to start and end AW ; seedlings not straight / too small to measure ; ruler doesn’t start at zero, i.e. additional plastic / wood ; 2 Ig parallax 1(a)(iii) observation: colour observed ; conclusion: correct conclusion for observation e.g. blue-black, starch present ; 2 1(b)(i) 1 time on x-axis + both axes fully labelled ; 2 linear scales with 2 values at origin + plots use at least half the grid on each axis ; 3 all 6 points correctly plotted ; 4 plots joined with ruled lines + no extrapolation to origin or beyond 23 days ; 4 1(b)(ii) growth or mean height increases + time / AW ; faster at start / slower at end ; 2 1(b)(iii) (between) 6–10 days ; 1 1(b)(iv) 0.8 ; mm / day ; 2 A mm per day 1(b)(v) any 2 variables: temperature / (sun)light / water or moisture / same type of seed / number of seeds or seedlings ;; explanation: to ensure that time / the variable you are investigating is the only variable that changes AW ; 3 1(c) 1 several (Petri) dishes ; 2 at least 5 seeds / seedlings in each (Petri) dish ; 3 water / solutions of different pHs used AW ; 4 at least 3 × pH numbers between 1–14 used ; 5 (control variables) temperature / (sun)light / same type of seed / volume of water ; 6 same length of time (minimum one day) ; 7 height of seedlings measured ; 8 sample of at least 3 seedlings + from each dish / pH ; 9 means calculated ; 6 2(a)(i) heart ; 1 2(a)(ii) blood vessel ; 1 A artery / vein R capillary Ig names 2(b) 1 clear and clean outline of heart drawn with a sharp pencil + no shading ; 2 heart at least 70 mm wide ; 3 height greater than width + tapering on both sides to curved base ; 4 surface blood vessel A from top right to bottom left of drawing ; 5 left atrium completely delimited + right atrium higher than left ; 5 2(c)(i) line drawn ; 40 ± 1 ; 2 2(c)(ii) horizontal line drawn at greatest width ; correct measurement to nearest mm ± 1 ; 2 2(c)(iii) measurement in (c)(ii) / measurement in (c)(i) ; correct answer rounded to 1dp ; 2

2 The photomicrograph shows the central part of a plant root as seen under a light microscope. magnification ×200 E G F (a) (i) The xylem and phloem are surrounded by a layer of tissue that is one cell thick. The cell labelled E is in this layer. Make a large drawing of cell E and the cells that touch it on the outside and inside of the layer. [4] (ii) Measure the diameter of the xylem vessel between F and G. … mm [1] (iii) Calculate the actual diameter of the xylem vessel. Space for working. diameter … mm [2] (b) Some of the outer cells in the photomicrograph contain small particles. Describe in detail how you would prepare a section of the root for observation under the microscope to see whether these cells contain starch. … … … … … … … … … … [5] [Total: 12]

2(a)(i) 5 cm minimum size ; outline of cell E drawn with sharp pencil + no shading anywhere; cell E with inner and lateral walls thick ; cell E + only two cells on inside and two cells on outside + both outside cells larger than inside cells ; 4 2(a)(ii) 17 ± 1 ; 1 2(a)(iii) measurement/200 ; 0.085 ; 2 2(b) cut thin slice of root ; place on (microscope) slide ; stain section with iodine ; add coverslip + prevent bubbles ; place slide on microscope + focus lens ; stains black if starch present ; 5

1 Which structures are present in plant cells but not in animal cells? A cell membrane, cytoplasm, chloroplasts B cell wall, chloroplasts, sap vacuole C cell wall, cell membrane, cytoplasm D cytoplasm, nucleus, chloroplasts

Answer: B To earn the mark, a student must identify the three structures (cell wall, chloroplasts, sap vacuole) that are unique to plant cells and absent in animal cells.

Cambridge O Level Biology · 5090

O-Level Biology (5090) Cells past paper questions

Revise O-Level Biology (5090) — Cells 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.

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

Cells in O-Level Biology 5090 exams, 2020–2025

Across 2020–2025, Cells accounted for 67 questions worth 376 marks in Cambridge O Level Biology (5090) papers.

By year
Year	Questions	Marks
2020	10	53
2021	12	68
2022	13	67
2023	9	64
2024	7	48
2025	16	76

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1.1 Cell structure and function304 marks
1.2 Specialised cells, tissues and organs91 marks

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Paper 1 · 38 qs
Paper 2 · 16 qs
Paper 3 · 11 qs
Paper 4 · 2 qs

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2021 May/Jun · Paper 2 · Q1 · 7 marks
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2021 Oct/Nov · Paper 3 · Q1 · 28 marks
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2021 May/Jun · Paper 3 · Q2 · 13 marks
Marking scheme
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2021 Oct/Nov · Paper 3 · Q2 · 12 marks
Marking scheme
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2021 May/Jun · Paper 1 · Q1 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q1
Answer: B
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Showing 5 of 44 free Cells questions.

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Cells in O-Level Biology 5090 exams, 2020–2025

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