We all know that we cannot live in this world healthy without regular intake of food. But most people do not know why we need food or why we are feeling hungry some times.  Hunger is body’s call for replenishing the food needed for the body. The food we have eaten earlier has been utilized for different activities and when restoration is needed it is shown to outside world in the form of hunger. What we have eaten earlier has given energy for the work we have been doing till now and the food we eat now will be used to continue the activities  and will be stored for future use also.

How food is converted into energy?

Conversion of food into energy is well explained in biochemistry.  Let us examine it step by step.

1. Food is split into basic unit known as glucose.  Glucose gets converted into energy in special cells known as mitochondria.  Breaking up of food into amino acids, glucose and fat takes place in the digestive system.
2. These glucose molecules break down and produce ATP in the cell.

Steps in the transformation of glucose into adenosine triphosphate are explained below.

Glucose contains carbon, hydrogen and oxygen and hence it is a carbohydrate.  When we eat carbohydrates their molecules are broken into smaller components. They are then converted into energy by mitochondria.   During the conversion process carbohydrates are broken into its constituents carbon dioxide and water.   The carbon dioxide we breathe out and the water is thrown out as urine.

On the other side plants breathe in carbon dioxide and leaves breathe out oxygen. Carbohydrates are formed as a result of the process known as photosynthesis which takes place in presence of sunlight.

Detailed procedure

Food we eat contains carbohydrates, fats, proteins etc. The food gets digested inside the stomach forming fatty acids, amino acids and glucose.  Glucose gets stored in liver. Amino acids help in the formation of protein and fatty acids are stored.

• When need arises glycogen is transformed to glucose and is released.
• The glucose in blood gets absorbed in every cell and tissue with the help of insulin.
• Glucose breaks into its constituents of acetyl-CoA
• Acetyl-CoA undergoes a process named KREB’s cycle.
• Acetyl-CoA releases 2 molecules of ATP which is broken into water and carbon dioxide.
• ATP provides energy for the movement of body, its processes etc.

Thus the food we eat breaks down to glucose which is converted into energy.