Principles of organisation

• Cell

  The basic building block of all living organisms

  
• Tissue

  A group of cells with a similar structure and function

  
• Organ

  Collections of tissues performing specific functions

  
• Organ system

  A system of organs which work together to form organisms

  
• Organism

  A living thing such as a plant, animal or single-celled life form

  
• Multicellular

  Organisms that are made of multiple cells

  
• Specialised cell

  A cell which has differentiated for a particular function

  
• Differentiation

  A process where a cell changes its structure to carry out a particular function

  
• Organelle

  A sub-cellular structure that carries out a specific function within a cell

  
• Examples of human tissues

  Muscular tissue and nervous tissue

  
• Examples of human organs

  Stomach and heart

  
• Examples of organ systems

  Digestive system and immune system

  
• Examples of plant tissues

  Epidermal tissue and palisade mesophyll

  
• Examples of plant organs

  Roots and stem