Respiration is a series of chemical reactions that release energy by breaking down large food molecules. It happens in every living cell. It is NOT breathing in and out.The energy released by respiration is used to power some of the chemical reactions that happen in cells.
Aerobic respiration needs oxygen to work. Most of the chemical reactions involved in the process happen in tiny objects inside the cell cytoplasm, called mitochondria.This is the equation for aerobic respiration:glucose + oxygen → carbon dioxide + water (+ energy) This the type of respiration you use most of the time. It take place in animal and plant cells and in some microorganisms.
Anaerobic Respiration takes place without oxygen. It take place when there place when there is little or no oxygen. It can be summarised by the following equation: glucose -----→ lactic acid (+ energy released)