Respiration in Animals Introduction

All living creatures need food. The food is consumed so that energy is obtained. The energy is utilised by the body for various purposes like locomotion, conduction of impulses, repair of damaged tissues, building of cell materials, etc.

The substance that is used to release energy is called the substrate. The food consumed has various chemical compounds such as carbohydrates, proteins, fats, etc. All these can be used by the body to give energy. Essentially, the body has a mechanism by which the food can be broken down into simpler molecules and in the process, release energy. The most common substrate for respiration is glucose.

Glucose breaks down in the presence of oxygen and gives carbon dioxide, water and energy. The energy is stored in the form of molecules called ATPs. They can be transported to the site of energy utilisation.

Definition

Thus, Respiration can be broadly defined as "the breakdown of organic compounds into simpler compounds accompanied by the release of energy in the form of ATP"

Since most often the substrate is glucose, the general equation for respiration can be written as follows