DNA replication only happens during meiosis because the chromosome number of the species remains the same from one generation to the next, the chromosome number of germ cells must be reduced by half during meiosis. To achieve this feat, meiosis, unlike mitosis involves a single round of DNA replication followed by two rounds of cell division.
Respiration using oxygen to break down food molecules is called aerobic respiration. 'Aero' means air, which contains oxygen, leading to the name aerobic respiration. Glucose is the molecule normally used for respiration - it is the main respiratory substrate. Glucose is oxidised to release its energy, which is then stored in ATP molecules.
The word equation for aerobic respiration is:
glucose + oxygen → carbon dioxide + water (+ ATP made)
You need to be able to recognise the chemical formulas:
C6H12O6 + 6O2 → 6CO2 + 6H2O
