Explain how cells are organised into tissues, organs and organ systems in a multicellular organism.

WJEC GCSE Biology (Wales) — 1.1.1 Cell structure and organisation · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

A tissue is a group of cells with a similar structure that work together to carry out a particular function. An organ is made up of different tissues that work together to perform a specific function. An organ system is a group of organs that work together to carry out a particular function. For example, muscle tissue forms the heart, which is an organ, and the heart is part of the circulatory system, an organ system.

Examiner tips

Use the exact wording from the mark scheme (tissue, organ, organ system).
Give a clear example at any level of organisation.
Show the hierarchy: cells → tissue → organ → organ system.
Keep the answer concise and to the point.

Common mistakes

Using vague terms like ‘group of cells’ without specifying similarity or function.
Giving an example that does not match the level asked (e.g., a cell type instead of tissue).
Omitting the hierarchy or mixing up the definitions of tissue, organ and organ system.

Mark scheme (4 marks)

A tissue is a group of cells with a similar structure working together to carry out a particular function
An organ is made up of different tissues working together to carry out a particular function
An organ system is a group of organs working together to carry out a particular function
A correct and relevant example given at any level of organisation (e.g. muscle tissue; heart/stomach as an organ; digestive/circulatory system as an organ system)

Key terms in this question

tissue · organ · organ system · multicellular organism