Respiration is the process of extracting energy from food. Respiration is a difficult concept for students to grasp. Therefore it is important to relate it to everyday life and build on the prior knowledge of the introductory biology topics.

Theory behind the hook

This hook makes links to students’ prior knowledge by using an everyday example of a fire burning and questions what is needed to ignite a fire. In this way students will be able to relate to the topic being introduced.

How this hook works

The hook begins with an engaging image of a fire and questions what is needed to ignite a fire. All students will know that fuel is needed, but this introduction also explains that oxygen is needed to produce heat energy/fire. This is analogous to what takes place in the human body. The next step of the clip involves explaining that we need energy for all our daily activities. As the introduction progresses an attempt is made to build on prior knowledge by asking questions about the human body’s fuel and oxygen source. Images of the food pyramid and the breathing system appear and are used to highlight the sources of oxygen and food for the body’s cells. Finally it is explained that oxygen is necessary to extract the energy from food, a process known as respiration.

Questions & Answers

  • Respiration involves an energy conversion. What energy conversion takes place?
    Respiration involves the conversion of chemical energy in food into heat energy.
  • Is glucose oxidised or reduced during respiration?
    Glucose is oxidised during respiration.
  • What are the waste products of respiration?
    Carbon dioxide and water.
  • What process utilises the waste products of respiration?

Cross Curricular Links

Links can be made to Junior Certificate Home Economics in which food and the breathing system is a central theme.


A graph could be drawn to illustrate how increased oxygen requirement for increased energy activities could be displayed and students could be asked to read from the graph and explain what they see.