Each and every cell in living organisms needs energy. These cells get their energy from oxidation of food.
Definition :- Respiration is a catabolic process in which organic food is oxidise to release energy.
Respiratory Substrate :- The organic food which is oxidise to release energy. Most common respiratory substrate is glucose.
The energy released during cellular respiration is immediately used to synthesise a energy rich compound ATP.
ADP+P = ATP
Respiration is an exothermic reaction, it means energy is liberated.
In our body ATP is used for the contraction of muscles, protein synthesis, conduction of nerve impulse, and many other activities.
Steps/Stages of Respiration
There are two steps in respiration :-
1. Glycolysis :- In this glucose molecule is firstly broken down to 2 molecule of three carbon compound, called pyruvic acid (CH3COCOOH).
The site of glycolysis is cytoplasm.it does not require oxygen.
2. Kreb cycle :- In this step glucose breakdown into carbondioxide, water, energy.
The site of kreb cycle is mitochondria. It require oxygen.
Types of Respiration
1. Aerobic Respiration :- In most of the organisms respiration involves use of molecular oxygen, this type of respiration is called aerobic respiration.
2. Anaerobic Respiration :- In some organisms respiration does not utilize molecular oxygen, this type of respiration is called anaerobic respiration. Exa. In yeast, or in muscle cell
Yeast, is a single celled fungus.it can respire anaerobically by –
Glucose → Pyruvic acid → 2ethyle alcohol+co2+E
Anaerobic respiration in muscle :- Muscle cells of our body (voluntary/striated muscle) can also respire anaerobically for short time, in them lactic acid is produced instead of alcohol.
Glucose → Lactic acid+Energy
Muscular Cramps :- when you run very fast, the muscle of your legs use lot of energy. This extra energy is produced in our muscle cells by anaerobic respiration. This activity accumulates lot of lactic acid in the muscles and blood. That accumulation of lactic acid in muscle cells causes cramp.
Blood Flow Chart
Differences Between Aerobic and Anaerobic Respiration
It does not use molecular O2.
It provide less energy.(2 ATP)
It occurs in the cytoplasm only
End Product :- CO2and water
It uses molecular O2.
It provides much more energy.(38ATP)
Partly in cytoplasm and partly in mitochondria.
End Product :- Ethanol, CO2,lactic acid.
Respiration in Plants
The gaseous exchange in plants differs from animals in several ways like :-
1. The plants do not have an organised respiratory system.
2. Plants are non motile and have low metabolic requirements,therefore,the respiration in plants occurs at slower rate.
Gaseous exchange in plants-
Plants are multicellular but they have a large surface area in comparison to their volume, as the surface area is large, diffusion alone can supply all the cells of the plant, with required oxygen. Diffusion occurs separately in the leaves, stem, and roots of plants :-
1. In leaves :- Diffusion occurs through stomata in the leaves.
2. Stem :- In woody plants the stem are covered with impermeable bark but the cork cells of bark are packed loosely at places, to allow oxygen to diffuse into the cells underneath. These holes of the stem are called LENTICLES.
3. Roots :- Gaseous exchange in roots generally takes place through root hairs of root epidermis.
Respiration in Animals
Terrestrial animals can breath the oxygen in the atmosphere but aquatic animal need to use the oxygen dissolve in water.
Due to this reason animals living in water expend more energy than lend animals.
Respiratory organs in different group of animals :-
Moist skin(Cutaneous resp.)
Amphibia, Reptiles, Birds, Man