- All organisms need food in order to survive.
- Once eaten, food reacts with oxygen to release energy (as well as water and CO2). This energy is used to keep cells working (and alive!).
- The energy of food is measured in kilojoules (kJ), or (kilo)calories (kcal). These can be found on food labels!
• 1 kJ = 1000 J
• 1 kcal = 4200 J