What is respiration? How it is …

All living organisms need a constant supply of energy. Respiration is the process of releasing energy through the breakdown of nutrients such as glucose. Respiration can be aerobic (uses oxygen) or anaerobic (does not use oxygen). Aerobic respiration takes place continuously in both plants and animals.

Respiration is a series of chemical reactions controlled by enzymes. Most of the reactions for aerobic respiration occur inside mitochondria. Mitochondria are structures inside plant and animal cells. They contain highly-folded inner membranes which are embedded with enzymes. These enzymes catalyse the reaction that releases energy from glucose.

Types of respiration

Aerobic respiration Aerobic respiration uses oxygen to break down glucose. Aerobic respiration can be described as the process of releasing energy through the oxidation of glucose molecules. Aerobic respiration releases lots of energy from each glucose molecule by breaking it down completely into carbon dioxide and water.

Anaerobic respiration takes place without oxygen. Anaerobic respiration is the incomplete breakdown of glucose. This process releases much less energy per glucose molecule than aerobic respiration and produces lactic acid. Anaerobic respiration occurs when cells have insufficient oxygen for aerobic respiration to occur, for example, during strenuous exercise.