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Bioinformatics combines Biology Topics with computational methods to analyze large datasets.
Similarities and Difference Between Aerobic and Anaerobic Respiration
Respiration usually takes place in the presence of oxygen (of air). Respiration can, however, also take place in the absence of oxygen of air, though it is very rare. This means that the breakdown of food (like glucose) to release energy can occur in the presence of oxygen as well as in the absence of oxygen. Based on this, there are two types of respiration : aerobic respiration and anaerobic respiration. These two types of respiration are discussed below.
1. Aerobic Respiration
The respiration which uses oxygen is called aerobic respiration. In other words, when the breakdown of glucose food occurs with the use of oxygen, it is called aerobic respiration. It is called aerobic respiration, because it uses ‘air’ which contains oxygen (‘aerobic means ‘with air). In aerobic respiration, the glucose food is completely broken down into carbon dioxide and water with the use of oxygen, and energy is released. The breaking down of food during aerobic respiration can be represented by means of a word equation as follows :
The energy released during aerobic respiration is used by the organism. Most of the living organisms carry out aerobic respiration (by using oxygen of air). For example, humans (man), dogs (see Figure), cats, lions, elephants, cows, buffaloes, goat, deer, birds, lizards, snakes, earthworms, frogs, fish, and insects (such as cockroach, grasshopper, houseflies, mosquitoes and ants, etc.), and most of the plants carry out aerobic respiration by using oxygen of air (to obtain energy).
All the organisms which obtain energy by aerobic respiration cannot live without the oxygen (of air). This is because if there is no oxygen, they cannot get energy from the food which they eat. Aerobic respiration produces much more energy because complete breakdown of glucose (food) occurs during aerobic respiration by the use of oxygen. The complete breakdown of glucose (food) produces carbon dioxide and water.
2. Anaerobic Respiration
The respiration which takes place without using oxygen is called anaerobic respiration. In other words, when the breakdown of glucose (food) occurs without the use of oxygen, it is called anaerobic respiration. It is called anaerobic respiration because it takes place without air which contains oxygen (‘anaerobic means ‘without air). The microscopic organisms like yeast (and certain bacteria) obtain energy by anaerobic respiration. In anaerobic respiration, the micro-organisms like yeast break down glucose (food) in the absence of oxygen to form alcohol and carbon dioxide, and release energy. The breaking down of glucose (food) during anaerobic respiration carried out by yeast can be represented by writing a word equation as follows :
The energy produced in this anaerobic respiration is used by the yeast. Only a few living organisms carry out anaerobic respiration to obtain energy (without using oxygen of air). For example, yeast (see Figure) and certain bacteria carry out anaerobic respiration in the absence of oxygen to obtain energy. All the organisms which obtain energy by anaerobic respiration can live without the oxygen (of air).
For example, yeast is an organism which can live without the oxygen of air because it obtains energy by the process of anaerobic respiration. Those organisms which obtain energy by the process of anaerobic respiration (without using oxygen) are called anaerobes. Thus, yeast is an anaerobe. Yeast can survive in the absence of oxygen.
Yeast is a single-celled organism. Actually, yeast is a single-celled fungus. In yeast, a single cell represents the whole organism. Yeast is used to make alcoholic drinks (such as wine and beer), and bread. This happens as follows: Yeast respires anaerobically and during this process, yeast converts glucose into alcohol. Yeast is, therefore, used in industry to make alcohol. This alcohol is used in making wine and beer.
Anaerobic respiration in yeast also produces carbon dioxide gas. In bread-making, the carbon dioxide produced by yeast makes the bread rise. Thus, anaerobic respiration in yeast is used to make alcohol (wine, beer, etc.) and bread. Anaerobic respiration (as in yeast) produces much less energy because only partial breakdown of glucose (food) occurs in anaerobic respiration in the absence of oxygen. The products of this partial breakdown of glucose (food) are alcohol and carbon dioxide.
Anaerobic Respiration in Muscles
We (human beings) normally obtain energy by aerobic respiration. But under certain conditions (when extra energy is needed), anaerobic respiration can take place in our muscles for a short time. When the oxygen gets used up faster in our muscle cells than can be supplied by the blood, then a temporary deficiency of oxygen occurs in the muscle cells. For example, when we do a heavy physical exercise (fast running, cycling or weightlifting, etc.), our muscles need a lot of energy.
To produce more energy, our muscles need more oxygen. But the supply of oxygen through blood is limited and hence insufficient. Under these conditions, anaerobic respiration takes place in the muscle cells (without oxygen) to produce extra energy and fulfil the demand for more energy. Thus, anaerobic respiration takes place in our muscle cells during any vigorous physical activity when oxygen gets used up faster in the muscle cells than can be supplied by the blood.
When anaerobic respiration takes place in our muscle cells in the absence of oxygen, then glucose (food) breaks down partially to form lactic acid and releases some energy. This extra energy helps us in doing hard physical exercise. The breaking down of glucose (food) during anaerobic respiration in muscles to release energy can be represented by a word equation as follows :
Please note that during heavy physical exercise (or any other hard work), most of the energy is produced by aerobic respiration. Anaerobic respiration in muscles provides only some extra energy which is needed under these circumstances (see Figure).
Please note that anaerobic respiration does not take place only in the muscles of human beings, it also takes place in the muscles of other animals such as lions, tigers, deer, etc., when they run very fast and require much more energy than normal.
After a heavy physical exercise (very fast running, etc.), we sometimes get muscle cramps (Painful contractions of muscles are called cramps) (see the man on right side in Figure 4). This can be explained as follows: During heavy exercise, some of our muscles respire anaerobically. The anaerobic respiration by muscles brings about partial breakdown of glucose (food) to form lactic acid.
This lactic acid accumulates in the muscles. The accumulation of lactic acid in the muscles causes muscle cramps. Thus, muscle cramps occur due to the accumulation of lactic acid in muscles when the muscles respire anaerobically (without oxygen) while doing hard physical exercise. We can get relief from cramps in muscles caused by heavy exercise by taking a hot water bath or a massage. Hot water bath (or massage) improves the circulation of blood in the muscles.
Due to improved blood flow, the supply of oxygen to the muscles increases. This oxygen breaks down lactic acid accumulated in muscles into carbon dioxide and water, and hence gives us relief from cramps. Before we end this discussion, we would like to give the main points of similarities as well as differences between aerobic respiration and anaerobic respiration. These are given below.
Similarities Between Aerobic and Anaerobic Respiration
| Aerobic respiration | Anaerobic respiration |
| 1. In aerobic respiration, energy is produced by the breakdown of food (like glucose). | 1. In anaerobic respiration also energy is produced by the breakdown of food (like glucose). |
| 2. Aerobic respiration takes place in the cells of the organism. | 2. Anaerobic respiration also takes place in the cells of the organism. |
Differences Between Aerobic and Anaerobic Respiration
| Aerobic respiration | Anaerobic respiration |
| 1. Aerobic respiration takes place in the presence of oxygen. | 1. Anaerobic respiration takes place in the absence of oxygen. |
| 2. Complete breakdown of food occurs in aerobic respiration. | 2. Partial breakdown of food occurs in anaerobic respiration. |
| 3. The end products in aerobic respiration are carbon dioxide and water. | 3. The end products in anaerobic respiration may be alcohol and carbon dioxide (as in yeast), or lactic acid (as in muscles). |
| 4. Aerobic respiration produces a considerable amount of energy. | 4. Much less energy is produced in anaerobic respiration. |