What is Respiration?
Respiration is one of the important chemical processes, which is carried out by all living organisms including plants animals and humans in order to release energy required for life processes. The process of respiration occurs both during the presence or in the absence of Oxygen
For instance, human beings undergo the process of respiration by inhaling oxygen gas and exhaling carbon dioxide gas. Many other living organisms including plants and animals undergo respiration process to obtain energy for their metabolic activities.
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The general diagram of the respiration process is as shown below:
Types of Respiration
Respiration is of two types, aerobic respiration, and anaerobic respiration.
Aerobic Respiration: It is the process of cellular respiration that takes place in the presence of oxygen gas to produce energy from food. This type of respiration is common in most of the plants and animals, birds, humans, and other mammals. In this process, water and carbon dioxide are produced as end products.
Anaerobic Respiration: It is a process which takes place in the absence of oxygen gas. In this process, the energy is obtained by the breakdown of glucose in the absence of oxygen. One of the best examples of anaerobic respiration is the process of fermentation in yeast.
Also refer: Aerobic And Anaerobic Respiration
Let us learn in detail about the Aerobic Respiration and its process
Aerobic respiration is a biological process in which food glucose is converted into energy in the presence of oxygen. The chemical equation of aerobic respiration is as given below-
|Glucose (C6H12O6) + Oxygen 6(O2) → Carbon-dioxide 6(CO2) + Water 6 (H2O) + Energy (ATP)|
According to the above-given chemical equation, energy is released by splitting the glucose molecules with the help of oxygen gas. At the end of the chemical reaction, energy, water molecules, and carbon dioxide gas are released as the by-products or end products of the reactions.
The 2900 kJ of energy is released during the process of breaking the glucose molecule and in turn, this energy is used to produce ATP – Adenosine Triphosphate molecules which are used by the system for various purposes.
Aerobic respiration process takes place in all multicellular organisms including animals, plants and other living organisms.
During the respiration process in plants, the oxygen gas enters the plant cells through the stomata, which is found in the epidermis of leaves and stem of a plant. With the help of the photosynthesis process, all green plants synthesize their food and thus releases energy.
Also refer: Transport Of Oxygen and Carbon Dioxide
The below-given chemical equation describes the complete process of photosynthesis or the aerobic respiration in plants.
|Carbon-dioxide 6(CO2) + Water 6 (H2O) → Glucose (C6H12O6) + Oxygen 6(O2)|
Steps of Aerobic Respiration
The complete process of Aerobic respiration occurs in four different stages:
It is the primary step of aerobic respiration is glycolysis and takes place within the cytosol of the cell. During the glycolysis process, the glucose molecules are splitting and separated into two ATP and two NADH molecules, which are later used in the process of aerobic respiration.
- Formation of Acetyl Coenzyme A
The second step in aerobic respiration is the formation of acetyl coenzyme A. In this process, pyruvate is oxidized in the mitochondria and 2-carbon acetyl group is produced. The newly produced 2-carbon acetyl group binds with coenzyme A, producing acetyl coenzyme A.
- Citric Acid Cycle
The third step in aerobic respiration is the citric acid cycle, which is also called the Krebs cycle. In this stage of Aerobic respiration, the oxaloacetate combines with the acetyl-coenzyme A and produces citric acid. The citric acid cycle undergoes a series of reactions and produces 2 molecules of carbon dioxide, 1 molecule of ATP, and reduced forms of NADH and FADH.
- Electron Transport Chain
This is the last step in aerobic respiration. In this phase, the large amounts of ATP molecules are produced by transferring the electrons from NADH and FADH. A single molecule of glucose creates a total of 34 ATP molecules.
Also refer: Respiratory Quotient
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