AQA GCSE Biology Foundation (8461), Foundation tier · Cell biology › Cell structure
Practise Cell specialisation. 5 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
How the structure of a specialised cell is adapted to its job: sperm, nerve and muscle cells in animals, and root hair, xylem and phloem cells in plants. The most common question is 'Explain how this cell is adapted to its function', often with a diagram and sometimes about a cell you have not met before.
Key facts
Specialised cell: structure adapted to carry out a particular function
Sperm: tail, many mitochondria, enzymes in the head, half the number of chromosomes
Nerve cell: long, with branched endings; carries electrical impulses
Muscle cell: protein fibres that slide to contract; many mitochondria
Root hair cell: large surface area; many mitochondria; no chloroplasts
Xylem: dead cells, hollow tubes, lignin; carries water and mineral ions upwards
Phloem: living cells, pores in end walls; carries dissolved sugars up and down
Notes
What a specialised cell is
A specialised cell has a structure adapted to carry out a particular function.
Its shape and its sub-cellular structures suit its job. Specialised cells work together in tissues, organs and organ systems.
Specialised animal cells
diagram
Sperm cell (reaches and fertilises an egg): a tail to swim; many mitochondria to release energy for swimming; enzymes in the head to digest a way into the egg; a nucleus with half the normal number of chromosomes.
Sperm cell
Nerve cell (carries electrical impulses around the body): long, to carry impulses over long distances; branched endings to connect with many other cells.
Muscle cell (contracts to cause movement): protein fibres that slide over each other to shorten the cell; many mitochondria to release energy for contraction; can store glycogen, which is broken down to glucose for respiration.
Specialised plant cells
diagram
Root hair cell (absorbs water and mineral ions from the soil): a long hair-like projection gives a large surface area; many mitochondria release energy for the active transport of mineral ions; no chloroplasts, as there is no light underground.
Root hair cell. There are no chloroplasts, because no light reaches the roots.
Xylem cells (carry water and mineral ions up from the roots): dead cells that form long hollow tubes with no end walls, so water flows through easily; walls strengthened with lignin.
Phloem cells (carry dissolved sugars up and down the plant): living, elongated cells joined end to end, with pores in the end walls so the cell sap can flow from one cell to the next.
Xylem and phloem
How to answer each type of question
Identify a specialised cell from its function
1 markGrade 3
Read the function carefully: what is carried, absorbed or done?
Match it to one cell: water and mineral ions in the soil (root hair), water up the stem (xylem), sugars (phloem).
Tick only the number of boxes asked for.
Example. Which type of cell carries dissolved sugars around a plant? Tick (✓) one box. ☐ Palisade cell ☐ Phloem cell ☐ Root hair cell ☐ Xylem cell
Show the model answerHide the model answer
Phloem cell (1)
Don’t lose marks
Listing features without saying what each one is for. Most marks need the feature and its purpose.
Saying mitochondria 'make energy'. Say they release energy by respiration.
Swapping xylem and phloem: xylem carries water and mineral ions; phloem carries dissolved sugars.
Saying xylem cells are living or that phloem cells are dead.
Saying a root hair cell has chloroplasts. It is underground, so it has none.
More tips
Memory tricks
Most adaptations are one of four ideas: a large surface area, many mitochondria (energy), a shape that suits the job, or structures that are missing because they would get in the way.
Phloem carries food (sugars): 'ph' and 'food' both start with an 'f' sound. Xylem carries water.
Wood is mostly xylem: dead, hollow and stiffened with lignin.
Exam technique
Use 'so that' after every feature: 'many mitochondria, so that more energy is released for swimming'.
If a diagram is given, use features you can see on it and name them precisely.
For an unfamiliar cell, ask: does it absorb (surface area), use a lot of energy (mitochondria) or carry something (shape)?
What each grade needs
What you need to be able to do, from the first marks up to the top grade.
Grade 3
Name specialised animal and plant cellsSperm, nerve and muscle cells in animals; root hair, xylem and phloem cells in plants.
Grade 4
State the function of each specialised celle.g. a nerve cell carries electrical impulses; phloem carries dissolved sugars.
Grade 5
Describe the adaptations of each specialised celle.g. a sperm cell has a tail, many mitochondria and enzymes in its head.
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Animals and plants contain specialised cells.
(a) Which cell is specialised to absorb water and mineral ions from the soil? Tick (✓) one box.[1]
Guard cell
Palisade cell
Root hair cell
Xylem cell
(b) Which cell carries electrical impulses around the body? Tick (✓) one box.[1]
Muscle cell
Nerve cell
Red blood cell
Sperm cell
(c) Sperm cells have a tail. Give the function of the tail.[1]
(d) Give one way a muscle cell is adapted to its function.[1]
Show the answer and mark scheme
(a)Answer: Root hair cell
(b)Answer: Nerve cell
(c)
to swim (to the egg)
(d)
contains many mitochondria (to release energy) / contains protein fibres that slide over each other to contract / can store glycogen
Question 2Medium6 marks
Root hair cells and xylem cells are specialised plant cells.
(a) Explain how the shape of a root hair cell helps it to absorb water.[2]
(b) Root hair cells contain many mitochondria. Explain why.[2]
(c) Xylem cells form long tubes that carry water through the plant. Give two ways that xylem cells are adapted to this function.[2]
Show the answer and mark scheme
(a)
the long hair / projection gives a large surface area
so more water is absorbed / water is absorbed faster (by osmosis)
(b)
mitochondria release energy by (aerobic) respiration
energy is needed for the active transport of mineral ions (from the soil)
(c)
the cells are dead / have no cytoplasm or nucleus
there are no end walls between the cells / they form continuous hollow tubes