IGCSE Biology: Organisation of the Organism — Practice Questions

These are original practice questions written in the style of Cambridge IGCSE Biology (0610) assessment objectives. They are not taken from any past paper and are not endorsed by Cambridge International.

Use these questions alongside the Organisation of the Organism study guide and revision notes. Every outcome in this topic’s cell-structure content is Core; the magnification unit-conversion skill in Section B is Supplement-only, as marked.

Section A — Core

1. State three structures found in a plant cell but not in an animal cell. [3]

2. State two structures found in a bacterial cell that are not found in either a plant or an animal cell. [2]

3. Name the specialised cell responsible for each function below.

(a) Photosynthesis (b) Transport of oxygen (c) Conduction of electrical impulses

[3]

4. Define the terms tissue and organ, and explain how they differ. [3]

5. State the formula linking magnification, image size and actual size. [1]

Section B — Core and Supplement

6. A diagram shows a plant cell, an animal cell and a bacterial cell side by side, but the labels have been removed.

(a) State one feature that would let you identify the plant cell immediately. [1] (b) State one feature that would let you identify the bacterial cell immediately, distinguishing it from both the plant and animal cell. [2]

7. A student writes: “Root hair cells and neurones are both specialised cells, but they are adapted for completely different jobs.”

(a) State the function of a root hair cell. [1] (b) State the function of a neurone, using the precise wording the syllabus requires. [1] (c) Explain, in general terms, what is meant by a cell being “specialised.” [2]

8. Put the following in order from smallest to largest level of biological organisation, and give one example of each from the human body: cell, organ, organ system, organism, tissue. [5]

9. A drawing of a cell measures 60 mm across. The actual cell is 0.04 mm across.

(a) Calculate the magnification of the drawing. Show your working. [2] (b) State the magnification as it would conventionally be written. [1]

10. (Supplement) A scale bar on a micrograph is given in micrometres (μm), but a student has measured the image size in millimetres (mm).

(a) State the conversion factor between millimetres and micrometres. [1] (b) Explain why the student must convert one of the two measurements before calculating magnification. [2]

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Answers

1. Any three of: cell wall, chloroplasts, permanent (large) vacuole [3, one mark each].

2. Any two of: circular DNA (in place of a nucleus), plasmids [2, one mark each; also accept “no true nucleus” as one distinguishing feature].

3. (a) Palisade mesophyll cell [1]. (b) Red blood cell [1]. (c) Neurone [1].

4. A tissue is a group of cells with similar structures working together to perform a shared function [1–2]. An organ is made of several different tissues working together to perform specific functions [1]. The key difference is that a tissue is built from one type of cell performing one job, while an organ combines several different tissues, each contributing a different job, to the organ’s overall function [1].

5. Magnification = image size ÷ actual size [1].

6. (a) The plant cell can be identified by having a cell wall (or chloroplasts, or a large permanent vacuole) which the animal cell lacks [1]. (b) The bacterial cell can be identified by having circular DNA instead of a nucleus, and/or plasmids [1–2], both of which are absent from the plant and animal cells shown.

7. (a) Absorption [1]. (b) Conduction of electrical impulses [1]. (c) A specialised cell has a structure adapted to carry out one particular function especially effectively [1], rather than being a generalised cell capable of many functions at once [1].

8. Cell (e.g. a red blood cell) → tissue (e.g. muscle tissue) → organ (e.g. the heart) → organ system (e.g. the circulatory system) → organism (e.g. a human being) [5, one mark per correctly placed level with a valid example].

9. (a) Magnification = image size ÷ actual size = 60 ÷ 0.04 = 1500 [2, one mark for correct substitution, one for the correct value]. (b) ×1500 [1].

10. (a) 1 mm = 1000 μm [1]. (b) Magnification can only be calculated correctly if both the image size and actual size are measured in the same unit [1]; mixing mm and μm without converting produces a magnification value that is out by a factor of 1000, so one measurement must first be converted so both are in the same unit before applying the formula [1].

A note on exam technique for this topic

The fastest way to lose easy marks on this topic is answering a comparison question (plant vs. animal vs. bacterial cell) with three separate, isolated descriptions instead of a direct comparison — examiners are specifically looking for you to state what one cell type has that another lacks, not simply list features of each in turn. Similarly, for the organisation hierarchy, resist answering with the five terms alone; the marks are usually attached to correctly matching each term to a fresh example the question supplies, not to reciting the sequence. For magnification questions, get into the habit of writing out the formula and checking both units match before you substitute numbers, since a fully correct method with a units error still loses the accuracy mark.