IGCSE Biology: Organisation of the Organism Practice Questions
Cells are the basic units of all living organisms. Plant cells contain a cellulose cell wall, chloroplasts and a permanent vacuole that animal cells lack, and cells become specialised so that their structure suits a particular function.
Topic 2 of Cambridge IGCSE Biology 0610 supplies the vocabulary used for the rest of the course, and it is the topic where the magnification formula appears. Marks are usually lost by describing a structure without giving its function, or by mishandling units in a magnification calculation. The questions below cover both.
What you need to know for Organisation of the Organism
- Structures in all cellsCell membrane controls what enters and leaves. Cytoplasm is where chemical reactions take place. Nucleus contains the genetic material and controls the cell. Mitochondria are the site of aerobic respiration. Ribosomes are the site of protein synthesis.
- Extra structures in plant cellsA cellulose cell wall for support, chloroplasts containing chlorophyll for photosynthesis, and a permanent vacuole containing cell sap that helps keep the cell turgid.
- Bacterial cellsA cell wall not made of cellulose, a cell membrane, cytoplasm, circular DNA and often plasmids. Bacteria have no nucleus, no mitochondria and no chloroplasts.
- Specialised cellsExamples include ciliated cells that move mucus, root hair cells that absorb water and ions, palisade mesophyll cells packed with chloroplasts, neurones that conduct impulses, and red blood cells that carry oxygen.
- Levels of organisationOrganelle, then cell, then tissue, then organ, then organ system, then organism. A tissue is a group of similar cells with a shared function. An organ is a group of different tissues working together.
- MagnificationMagnification = image size divided by actual size. Convert both measurements to the same unit before dividing. 1 mm equals 1000 micrometres.
IGCSE Biology Organisation of the Organism questions and answers
4 exam-style questions written to the 0610 syllabus. Try each one on paper first, then open the worked answer to check your method against the marks.
Name three structures found in a plant cell but not in an animal cell, and state the function of each.
Show the worked answer
- Cell wall, made of cellulose. It gives the cell strength and support and stops it bursting when it takes in water.
- Chloroplast, containing chlorophyll. It absorbs light energy for photosynthesis.
- Permanent vacuole, filled with cell sap. It stores water and dissolved substances and keeps the cell turgid, which supports the plant.
- Note that a cell membrane, nucleus, cytoplasm, mitochondria and ribosomes are found in both types of cell, so none of those can be used.
A student views a cell under a microscope. The image of the cell measures 60 mm across and the actual cell is 0.15 mm across. Calculate the magnification.
Show the worked answer
- Use magnification = image size divided by actual size.
- Both measurements are already in millimetres, so no conversion is needed.
- Magnification = 60 divided by 0.15.
- Magnification = 400, written as x400. Magnification has no units because it is a ratio of two lengths.
Describe two ways in which a root hair cell is adapted for absorbing water and mineral ions from the soil.
Show the worked answer
- The cell has a long, narrow hair-like extension that projects into the soil.
- This greatly increases the surface area in contact with soil water, so water can be absorbed faster by osmosis.
- The cell contains many mitochondria.
- These release energy by aerobic respiration, which is needed for the active transport of mineral ions into the cell against their concentration gradient.
Define the terms tissue and organ, giving one example of each from a named organism.
Show the worked answer
- A tissue is a group of cells with similar structures, working together to perform a shared function.
- An example is muscle tissue in a human, or xylem tissue in a plant.
- An organ is a structure made of a group of different tissues, working together to perform a particular function.
- An example is the heart in a human, or a leaf in a plant.
Common mistakes in this topic
- Writing that plant cells have a cell wall instead of a cell membrane. They have both.
- Confusing chlorophyll with chloroplast. Chlorophyll is the green pigment. The chloroplast is the organelle containing it.
- Mixing units in magnification calculations. Convert to a single unit first.
- Saying bacteria have a nucleus. Bacterial DNA is circular and lies free in the cytoplasm.
- Describing a specialised cell without linking the feature to the job it performs.
Exam tips
- Learn the cell structures as a table with a function column. Almost every question in this topic asks for structure and function together.
- For magnification, write the triangle or the formula first. The formula alone often scores a mark.
- Convert millimetres to micrometres by multiplying by 1000, and the other way by dividing.
- When drawing a biological diagram, use clean single lines, no shading, and label lines drawn with a ruler that do not cross.
- Any question about a specialised cell wants two things: the feature and why that feature helps.
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Organisation of the Organism FAQs
What is the difference between a plant cell and an animal cell?
Both have a cell membrane, cytoplasm, nucleus, mitochondria and ribosomes. A plant cell also has a cellulose cell wall for support, chloroplasts for photosynthesis and a permanent vacuole containing cell sap. Animal cells have none of those three.
How do I calculate magnification in IGCSE Biology?
Divide the size of the image by the actual size of the specimen, after converting both to the same unit. If the image is 60 mm and the real cell is 0.15 mm, the magnification is 60 divided by 0.15, which is 400. Magnification is a ratio, so it has no units.
What are the levels of organisation in order?
Organelle, cell, tissue, organ, organ system, organism. A tissue is a group of similar cells performing a shared function, an organ is several different tissues working together, and an organ system is a group of organs with a related function such as the digestive system.
How is a bacterial cell different from a plant or animal cell?
Bacteria have no nucleus, no mitochondria and no chloroplasts. Their genetic material is a circular loop of DNA lying free in the cytoplasm, often with smaller rings called plasmids. They do have a cell wall, but it is not made of cellulose.
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Written to the published Cambridge IGCSE Biology (0610) syllabus. Check your school entry code and syllabus year, because Core and Extended candidates are assessed on different content. Last reviewed 2026-08-12.