Cell differentiation: Many types of plant cells retain the ability to differentiate throughout life.

The idea

Differentiation is the process by which a cell becomes specialised for a particular job. In many plants, unspecialised cells remain in tissues such as the root tip, shoot tip and cambium, and can divide and then differentiate throughout the plant's life. This allows growth, replacement of damaged parts and regrowth after grazing or pruning. For example, cells produced at a root tip can differentiate into root hair cells with a large surface area for water uptake, or into xylem vessels that transport water and support the stem. Meristem tissue can also be cultured to produce clones of a plant, which is useful in horticulture and conservation. In animals, by contrast, most differentiation occurs during development and mature animals mainly use division for repair and replacement.

What earns the marks

• Differentiation means a cell becomes specialised to carry out a particular function.
• Many plant cells remain unspecialised in meristems, such as root tips, shoot tips and cambium.
• Examples of plant specialisation include root hair cells for water and mineral uptake, xylem for transport and support, and palisade cells for photosynthesis.
• Meristem cells can be used to produce clones of plants, which is useful in agriculture and conservation.

Common mistakes and how to put them right

• Thinking that all plant cells can differentiate anywhere in the plant.

  Put it right: The ability is mainly retained by unspecialised meristem cells in regions such as root tips, shoot tips and cambium.

• Confusing differentiation with cell division.

  Put it right: Division produces more cells, whereas differentiation changes a cell's sub-cellular structures so it becomes specialised.

• Assuming plants stop differentiating after they mature.

  Put it right: Many plants continue to differentiate throughout life, which is why they can regrow after pruning or grazing.

Exam tips

• Link the statement to named plant tissues such as root tip, shoot tip and cambium rather than saying 'plants' generally.
• When describing a specialised plant cell, name the cell and state how its sub-cellular structures suit its function, for example root hair cell with a long extension for a large surface area.
• Use the term meristem accurately and distinguish it from a general unspecialised cell.
• If asked to compare plants and animals, state that mature animals mainly divide for repair and replacement, whereas many plants retain differentiation throughout life.