ATP

In the syllabus and the exam

ATP is introduced in the respiration content standard as the direct energy currency of the cell, released in small, immediately usable packets rather than stored as heat the way ordinary combustion would release it. Learners must be able to state that respiration transfers chemical energy from glucose into ATP, and that ATP is then used for processes such as active transport, muscle contraction, protein synthesis, cell division and nerve impulse transmission. Exam items often ask candidates to explain why organisms need a continuous supply of ATP rather than storing a large stockpile of it, since ATP is broken down and resynthesised constantly rather than accumulated. A frequent misconception is treating ATP as a fuel like glucose; candidates should instead describe it as an intermediate energy carrier that is repeatedly built up in respiration and broken down when a cell does work, releasing energy plus ADP and inorganic phosphate.

Example

ATP produced during the light-dependent stage of photosynthesis is used in the light-independent stage to reduce carbon dioxide into glucose.

Related terms

Cellular respirationAerobic respirationAnaerobic respiration

Source:SRC-DSKP-EN