The process of releasing energy from food is called Respiration. It involves taking in O2 into the cells, using it for releasing energy by burning food and then eliminated the waste products from body of human. It is essential process for life because it provides energy for carrying out the entire organism alive.
Breathing and Respiration
- The mechanism by which organism obtain O2 from air and release CO2 is called as breathing. While respiration includes breathing and oxidation of food in cells of organism to release energy.
- Breathing is physical process while respiration is a biochemical process that requires many enzymes.
- Breathing involves with the lungs. While the respiration involves with the mitochondria of cells where food is oxidised.
- Respiration is just opposite to the photosynthesis. Because photosynthesis makes food by using CO2, water and sunlight and releasing O2 where as respiration breaks food (like glucose) by using O2 and release CO2, water and energy.
Types of Respiration
Aerobic respiration is that which carried out in the presence of oxygen. Here the glucose molecule completely breakdown into CO2 and water. It produces large amount of energy that stored in the form of ATP molecules. Mitochondria are the sites of aerobic respiration in the cells.
Anaerobic respiration is that which takes place in absence of O2. Microscopic bacteria and some yeast obtain energy by this method. In this glucose breakdown into the ethanol and CO2 and release energy. This energy is then used by m/o. It produces much less energy.
Respiration in plants
Respiration in plants occurs at a slow rate. On the other hand, respiration in animals occurs at a much faster rate. During respiration in plants, there is a little transport of respiratory gases from one part of the plant to the other. On the other hand, respiratory gases are usually transported over long distances inside an animal during respiration.
Respiration in roots
Air presents in b/w the particles of soil. Roots of plants take the O2 required for respiration by the process of diffusion. Oxygen diffuses in root hairs and reaches all other cells of root for respiration. Carbon-di-oxide gas is produced in the cells of root during the respiration moves out through the same root hairs by process of diffusion.
It is noted that land plant die if their roots remain water logged for a considerable time. This is because too much water expels O2 from soil particle. Due to this, oxygen is not available to roots for aerobic respiration so roots respire an-aerobically, producing the alcohol that kill the plant body.
Respiration in stems
The hard and woody stems of big plants or trees do not have stomata. In woody stems bark has lenticles for gaseous exchange. The oxygen from air diffuses into the stem of a woody plant through lenticles and reaches all the inner cells of the stem for respiration. CO2 produced are also diffuse out through it.
Respiration in leaves
Exchange of respiratory gases in the leaves takes place by the process of diffusion through the stomata. Oxygen from air diffuses in respiration in leaves occurs during the day time as well as at night. On the other hand photosynthesis occurs only during the day time.
Day time when photosynthesis occurs O2 is produced. Leaves use some of this O2 for respiration and rest of O2 diffuses out into air during day time, CO2 produced by respiration is all used up in photosynthesis by leaves. Even more CO2 is taken in from air. Thus net gas exchange in leaves during day time is; O2 diffuse out & CO2 diffuse in.
Night time when no photosynthesis occurs and hence no O2 is produced, O2 from air diffuses into leaves to carry to carry out respiration and CO2 produced by respiration diffused in and CO2 diffused out.