Respiration

The process by which a living being utilizes the food to get energy is called respiration.
Respiration is an oxidation reaction that involves sequential degradation of food and generation of energy.
Mitochondria is the site of respiration and the energy released is stored in the form of ATP (Adenosine triphosphate)
The respiratory system provides the route by which the oxygen present in our environment gains entry into the body and the carbon dioxide produced is excreted.

Breathing: This whole process of exchange of gases is called breathing

STEPS OF RESPIRATION:

1. Breaking down glucose into pyruvate:

This step happens in the cytoplasm. Glucose molecules are broken down into pyruvic acid.
Glucose molecule is composed of 6 carbon atoms, while pyruvic acid is composed of 3 carbon atoms.
Fate of Pyruvic Acid: Further breaking down of pyruvic acid takes place in mitochondria and the molecules formed depend on the type of respiration in a particular organism.

Respiration is of two types, viz. aerobic respiration and anaerobic respiration.

Aerobic Respiration:

This type of respiration happens in the presence of oxygen.
Pyruvic acid is converted into carbon dioxide.
Energy is released and water molecules are also formed at the end of this process.

Anaerobic Respiration:

This type of respiration happens in the absence of oxygen.
Pyruvic acid is either converted into ethyl alcohol or lactic acid.
Ethyl alcohol is usually formed in case of anaerobic respiration in microbes; like yeast or bacteria.
Lactic acid is formed in some microbes as well as in the muscle cells.