Respiration (HL IB ESS OLD COURSE - IGNORE)

Revision Note

Respiration

  • Respiration is the conversion of organic matter into carbon dioxide and water in all living organisms, releasing energy

    • Cellular respiration releases energy from glucose by converting it into a chemical form that can easily be used in carrying out active processes ( such as growth and repair) within living cells

    • The aerobic respiration reaction is:

Word equation for aerobic respiration, IGCSE & GCSE Chemistry revision notes

Aerobic respiration

  • The inputs and outputs are:

    • Inputs: organic matter (glucose) and oxygen

    • Processes: oxidation processes inside cells

    • Outputs: release of energy for work (movement) and heat

    • Transformations: stored chemical energy is transformed into kinetic energy and heat

  • Some of the chemical energy released during cellular respiration is transformed into heat

    • Heat is generated by cellular respiration because it is not 100% efficient at transferring energy from substrates, such as carbohydrates, into the chemical form of energy used in cells

    • Heat generated within an individual organism cannot be transformed back into chemical energy and is ultimately lost from the body

    • The heat energy released increases the entropy in the ecosystem, following the second law of thermodynamics, while enabling organisms to maintain relatively low entropy (high organisation)

Examiner Tips and Tricks

You are not required to know that adenosine triphosphate (ATP) is the readily usable energy currency of cells, just remember that the energy released by respiration is used in carrying out active processes within living cells.

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