3 The diagram shows an elm tree. (a) Elm trees may be infected by a fungus that causes a disease. State two characteristics of a fungus. 1 … 2 … [2] (b) The fungus moves through an infected tree inside the xylem vessels. The tree responds to stop the movement of the fungus by producing substances that block the xylem vessels. This causes the leaves of the tree to wilt and to become yellow. Explain how the response of the tree to infection leads to these symptoms of disease. … … … … … … … … … … [5] (c) An insect called the elm bark beetle is the vector of this disease. Describe what is meant by the term vector. … … … … [2] (d) Elm trees can reproduce when the roots from one parent tree spread out near the surface of the soil. This is shown in the diagram below. roots of parent tree grow stems called suckers each sucker forms a new tree (i) Name the type of reproduction shown in the diagram. … [1] (ii) Suggest why this type of reproduction makes it difficult to control the spread of the disease caused by the fungus. … … … … … … [3] [Total: 13]

3(a) 1 hyphae / mycelium ; 2 saprotrophic / saprophytic / feeds on dead matter AW / decomposer ; 3 spores ; 4 cell wall + chitin ; 5 more than one nucleus / multinucleate ; 2 3(b) 1 less / no + water transported / water absorbed / transpiration ; 2 water loss greater than water uptake ; 3 less + water in cells ; 4 flaccid / loss of turgor / plasmolysed ; 5 magnesium / Mg ; 6 less / no + chlorophyll ; 5 3(c) 1 transfer / carries / spreads AW + pathogen / fungus / parasite ; 2 one organism AW to another ; 3 not itself + affected / infected ; 2 3(d)(i) asexual ; 1 3(d)(ii) 1 close together ; 2 connected AW ; 3 genetically identical / all genetically susceptible / clones ; 3

3 The photograph shows a leaf of a southern beech tree. teeth on leaf edge F G magnification ×1 (a) (i) Make a large drawing of the leaf in the space below. [5] (ii) On the photograph draw a straight line to join F and G. Measure and record the length of the line. … On your drawing draw a straight line in the same position as on the photograph. Measure and record the length of the line. … [3] (iii) Calculate the magnification of your drawing compared to the original size of the leaf. Space for working. magnification × … [2] (b) Biological keys can be used to identify species. A biological key for five different species of southern beech tree is shown below. Use this key to identify the name of the tree whose leaf is shown in the photograph on page 8. To use the key start at 1 and read the two alternatives, (a) and (b). Decide which one is correct and tick [3] the box next to that option. If indicated, go to the next number. Continue with this procedure until you identify the tree leaf in the photograph. 1 (a) Leaf with a smooth edge mountain beech (b) Leaf with teeth on edge go to 2 2 (a) Leaf 20–40 mm long go to 3 (b) Leaf 6–15 mm long silver beech 3 (a) Leaf with 4–7 teeth on each side red beech (b) Leaf with 8–12 teeth on each side hard beech name of tree … [2] [Total: 12]

3(a)(i) drawing at least 8 cm long ; drawn with a sharp pencil + continuous lines + no shading ; leaf length greater than width + stalk drawn with double line + closed at end ; four teeth on left side of leaf + five teeth on right side of leaf ; smooth edge to leaf + first point on right higher then left ; 5 3(a)(ii) measurement for F-G in photograph 34–36 ; two lines drawn in same positions ; correct measurement of candidate’s line on drawing ± 1 mm + correct unit ; 3 3(a)(iii) working shown ; length in photograph / length of drawing ; 2 R units 3(b) boxes 1b + 2a ticked ; red beech ; 2

1 Spirulina is classified in the group bacteria. Spirulina is green in colour and is able to synthesise its own food. (a) List three characteristics of bacteria. 1 … 2 … 3 … [3] (b) (i) Suggest the name of the chemical that gives Spirulina its green colour. … [1] (ii) Write, in words or symbols, the equation for the process by which Spirulina synthesises its own food. … → … [2] (c) Spirulina can be eaten by humans. The United Nations World Health Organization (WHO) made the following statement about Spirulina: ‘For WHO Spirulina represents an interesting food for multiple reasons. Rich in iron and protein, it can be given to children without any risk. We at WHO consider it to be a very suitable food.’ Use your knowledge of animal nutrition to suggest and explain why WHO considers Spirulina to be a ‘very suitable food’. … … … … … …[4] [Total: 10]

1(a) single-celled ; no nucleus / nucleus not membrane bound ; no organelles ; cell wall ; (cell wall) not cellulose ; cell membrane / cytoplasm ; flagella / flagellum ; DNA circular / loop OR plasmid / single chromosome ; smaller than animal / plant cells OR 1–2 µm ; 3 1(b)(i) chlorophyll ; 1 1(b)(ii) carbon dioxide / 6CO2 + water / 6H2O ; glucose / C6H12O6 + oxygen / 6O2 ; 2 1(c) iron + haemoglobin / red blood cells ; prevent anaemia ; protein + growth / repair ; protein + (production of) enzymes / antibodies ; carbohydrates / glucose / starch / vitamins / ions ; reference to a component of balanced diet / dietary supplement OR to alleviate malnutrition / famine ; 4 Total: 10 (a) To earn marks, you need to list three distinct characteristics of bacteria, such as being single-celled, lacking a membrane-bound nucleus or organelles, having a cell wall (not cellulose), or possessing flagella. (b)(i) You score by correctly naming 'chlorophyll' as the green chemical. (b)(ii) You earn marks by writing the correct reactants (carbon dioxide and water) and products (glucose and oxygen) for photosynthesis, either in words or chemical symbols. (c) To score, you must suggest and explain why Spirulina is a suitable food, linking its iron content to haemoglobin and preventing anaemia, and its protein content to growth, repair, or enzyme/antibody production, or by mentioning its role as a component of a balanced diet or in alleviating malnutrition.

26 The diagram shows the structure of a bacterium. In what way does this differ from a cell of a fungus? A The bacterium has a cell membrane. B The bacterium has a cell wall. C The bacterium has cytoplasm. D The bacterium has no true nucleus.

Answer: D To earn the mark, a student must state that a bacterium differs from a fungus cell because it lacks a true nucleus.

26 The diagram shows the structure of a bacterium. In what way does this differ from a cell of a fungus? A The bacterium has a cell membrane. B The bacterium has a cell wall. C The bacterium has cytoplasm. D The bacterium has no true nucleus.

Answer: D To earn the mark, a student must identify that a key difference between a bacterium and a fungus cell is that the bacterium lacks a true nucleus.

Cambridge O Level Biology · 5090

O-Level Biology (5090) Classification past paper questions

Revise O-Level Biology (5090) — Classification 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.

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

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

Across 2020–2025, Classification accounted for 35 questions worth 192 marks in Cambridge O Level Biology (5090) papers.

By year
Year	Questions	Marks
2020	3	17
2021	5	17
2022	3	3
2023	7	44
2024	11	78
2025	6	33

Most-tested subtopics

2.2 Features of organisms155 marks
2.1 Concept and use of a classification system94 marks

Appears in

Paper 1 · 21 qs
Paper 2 · 9 qs
Paper 3 · 2 qs
Paper 4 · 3 qs

All most-tested Biology topics

2021 May/Jun · Paper 2 · Q3 · 13 marks
Marking scheme
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2020 Oct/Nov · Paper 3 · Q3 · 15 marks
Marking scheme
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2017 May/Jun · Paper 2 · Q1 · 10 marks
Marking scheme
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2021 May/Jun · Paper 1 · Q26 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q26
Answer: D
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2021 May/Jun · Paper 1 · Q26 · 1 mark
Marking scheme
Mark scheme — 2021 Paper 1 Q26
Answer: D
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