Cell specialisation: Cells may be specialised to carry out a particular function:

The idea

Specialisation means a cell develops features that make it efficient at one job. In multicellular organisms, cells arise from mitosis and then differentiate: they switch on genes for particular proteins, changing their shape and organelles. For example, a root hair cell grows a long extension to increase surface area for water uptake, while a red blood cell loses its nucleus to pack in haemoglobin. Specialisation therefore links structure to function. It allows division of labour, so tissues and organs work efficiently. The process is controlled by genes, and the resulting cell cannot usually change back. When answering, name the cell, state its job, then explain how each feature helps.

What earns the marks

• Define specialisation as the process by which a cell develops specific structures or features suited to a particular function.
• Explain that specialisation occurs through differentiation, in which particular genes are expressed so that specific proteins are made.
• Link at least one named cell structure to its function, for example many mitochondria in a muscle cell release energy for contraction.
• Describe how specialisation allows division of labour in multicellular organisms, with different cells carrying out different jobs.
• Recognise that specialised cells usually have a limited ability to divide or change into other cell types.

Common mistakes and how to put them right

• Saying a specialised cell 'decides' to change.

  Put it right: Specialisation is controlled by gene expression, not conscious choice.

• Describing a feature without linking it to function.

  Put it right: State how the feature helps the cell carry out its job.

• Confusing differentiation with mitosis.

  Put it right: Mitosis produces genetically identical cells; differentiation makes them structurally and functionally different.

Exam tips

• Use the structure-to-function chain: feature → how it increases efficiency → benefit to the organism.
• When asked to explain, avoid simply listing cell parts; each part needs a consequence.
• Use precise terms such as differentiate, gene expression, surface area and concentration gradient.