Respiration
Whit is Respiration?
Respiration is a bio-chemical process which involves:
- Intake of environmental oxygen.
- Oxidation of food (simple food molecules such a glucose)
- Removal of carbon dioxide produced in oxidation.
- Released of energy which is changed into biological useful form of energy ATP (adenosine triphosphate) molecules.
Thus, respiration is the process which involves exchange of environmental oxygen with carbon dioxide produced in the body during oxidation of food for the release of energy.
Breathing and Respiration
Mechanism by which an organism obtains oxygen from the environment and removes carbon dioxide is called breathing. Thus, intake of fresh air from the environment and removal of foul air (air having more CO2) from the body is called breathing. It is a physical process. Respiration is more complex process it includes:
1. Breathing
2. Oxidation of digested food occurring in the cell in order to release energy.
Energy produced during respiration it utilized from performing various metabolic activities (i.e. biological functions) essential for survival and maintenance of an organism.
Respiration is a biochemical process taking place in the cytoplasm and mitochondria. It occur in many steps and requires many enzymes. Main outcome of respiration is the release of energy by oxidation of food such as glucose.
Difference between breathing and
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Breathing |
Respiration |
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I. It is a biochemical process which involves exchange of gages and oxidation of food. II. It occur within the cell and hence it is an intracellular process. III. It released energy in the form of ATP. IV. It involves a large number of enzymes. V. It occur in all cell of the body. |
Difference between combustion (burning) and respiration.
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Combustion (burning)
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Respiration |
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It is a bio-chemical process. |
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It occur in cell. |
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In it chemical bonds break in steps, releasing energy in steps. |
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Temperature remains low within limits. |
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No light is produced. |
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It is an enzymatically controlled process. |
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It occur in a controlled manner. |
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Several intermediates are produced in it. |
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Most of the energy is trapped in ATP molecules. |
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10. Most of the energy released dissipates as heat. |
Little energy produced is lost. |
Types of respiration.
Oxidation of food for the release of energy may occur in presence or absence of oxygen. Hence, respiration is of two types as:
I. Aerobic respiration: Majority of organisms accepts certain anaerobic bacteria, yeast and endoparasites use molecular oxygen for oxidation of food to release energy. When food is oxidized in the presence of oxygen, the respiration is said to be aerobic. Organisms having aerobic respiration are called aerobes. During aerobic respiration, food (glucose) is completely broken down in carbon dioxide and water by the process of oxidation. This results in the production of energy (ATP).
C6H12O6 + 6O2 ------> 6CO2 + 6H2O + Energy
(Glucose) (Oxygen) (Carbon dioxide) (Water)
The above shown reaction occurs in both cytoplasm and mitochondria of the cells. It occurs in many steps and requires many enzymes. In cytoplasm glucose is changed to pyruvic acid and the process is called glycolysis. During glycolysis no oxygen is needed. Pyruvic acid by a cyclic process is called Krebs’s cycle is oxidized to form carbon dioxide and water with release of more energy.
glycolysis Krebs’s cycle ECT
Glucose --------------> pyruvic acid --------------------> CO2 + H2O +Energy
No oxygen O2 required
II. Anaerobic respiration: It occurs in few organisms, such as certain anaerobic bacteria, yeast and many endoparasites like Taenia. It also occurs in our muscles during vigorous muscular activity, when oxygen gets used up faster than it is available to muscles cells. It also occurs in human red blood corpuscles.
It occurs in absence of molecular oxygen. It is also known as fermentation. In this process food is incompletely degraded so, only a part of energy (15%) is released. Organisms showing anaerobic respiration are called anaerobes.
In case of bacteria, muscles and endoparasites the end products of anaerobic respiration is lactic acid. But is case of yeast and some plants the end product of anaerobic respiration is ethyl alcohol. The overall equation for this is given here;
In yeast:
Glycolysis Fermentation
Glucose ---------------> Pyruvate ------------------> C2H5OH + H2O + Energy
No oxygen no Oxygen ethyl alcohol
In muscles:
Glycolysis Fermentation
Glucose ---------------> Pyruvate ------------------>Lactic acid + Energy
No oxygen no Oxygen