Cell structure — Cambridge IGCSE Biology
Structure and function of plant, animal and bacterial cells, specialised cells, and the levels of organisation from cell to organism.
Revision notes
4 short notes, in the order of the specification. Each one in short:
Plant and animal cells both have a cell membrane, cytoplasm, a nucleus, ribosomes and mitochondria. Plant cells also have a cellulose cell wall that strengthens the cell, chloroplasts that absorb light energy for photosynthesis, and a large vacuole containing cell sap. The cell wall is fully permeable, while the cell membrane controls what enters and leaves.
A bacterial cell is a simple cell with a cell wall, cell membrane, cytoplasm and ribosomes but no nucleus. Its genetic material is a single loop of circular DNA lying free in the cytoplasm, and it may also have plasmids, which are small rings of extra DNA. Its cell wall is not made of cellulose.
A specialised cell is a cell with a specific function, whose shape and contents suit it to that job. Root hair cells have a long extension for absorption, red blood cells contain haemoglobin for the transport of oxygen, and ciliated cells move mucus in the trachea and bronchi. New cells are produced by division of existing cells.
Organisms are organised in levels: cell, tissue, organ, organ system and organism. A tissue is a group of cells with similar structures working together to perform a shared function. An organ is a group of tissues working together, and an organ system is a group of organs with related functions, such as the digestive system.
Exam questions
7 exam-style questions (18 marks), each with its mark scheme.
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17 cards: flip them, mark what you knew, and practise the rest.
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The whole of organisation of the organism on one page, so you can see where this subtopic fits.
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Quick check questions
Name three structures found in plant cells but not in animal cells.
Show answer
Cell wall, chloroplasts and a large vacuole.
Where is the DNA in a bacterial cell?
Show answer
Circular DNA, free in the cytoplasm; there is no nucleus.
How are new cells produced?
Show answer
By division of existing cells.
Which specialised cell transports oxygen?
Show answer
The red blood cell.
Put in order, smallest first: organ, cell, organism, tissue, organ system.
Show answer
Cell, tissue, organ, organ system, organism.
Frequently asked questions
What is the difference between plant and animal cells?
Plant cells have a cellulose cell wall, chloroplasts and a large vacuole containing cell sap, which animal cells do not have. Both types of cell have a cell membrane, cytoplasm, a nucleus, ribosomes and mitochondria. In an exam, name a structure only one cell has, for example 'plant cells have a cell wall, animal cells do not'.
Why do plant cells have a cell wall?
Plant cells have a cell wall because it strengthens the cell and supports it. The wall is made of cellulose and is fully permeable, so it does not control what enters the cell; that is the job of the cell membrane. The large vacuole of cell sap also helps keep the cell firm.
What is the difference between a bacterial cell and a plant cell?
A bacterial cell has no nucleus, chloroplasts or large vacuole. Its DNA is a single circular loop free in the cytoplasm, often with extra rings called plasmids. Like a plant cell, it has a cell wall, cell membrane, cytoplasm and ribosomes, but the bacterial cell wall is not made of cellulose.
How are root hair cells adapted to their function?
Root hair cells are adapted for absorption. Each has a long extension, the root hair, which gives a large surface area for the uptake of water and mineral ions from the soil. In Cambridge answers, state the function as absorption and link it to the large surface area of the extension.
What is the difference between a tissue and an organ?
A tissue is a group of cells with similar structures, working together to perform a shared function, such as muscle tissue. An organ is a structure made up of a group of tissues working together to perform specific functions, such as the stomach or the leaf. Organs with related functions form an organ system.
Written and checked against the Cambridge IGCSE Biology (0610) specification · Updated October 2026