Question 1 What is meant by respiration?
Question 2 What is the difference between aerobic and anaerobic respiration?
Question 3 List the similarities between aerobic and anaerobic respiration?
Question 4 What is meant by aerobic respiration ? Name organism which normally uses aerobic respiration?
Question 5 Define the term cellular respiration?
Question 6 What type of respiration takes place in human muscles during heavy exercise? Explain?
We need energy to perform all activities which maintain our life, and also to do work. The stored energy of food is released slowly during the process of respiration which takes place inside our body all the time. It is this energy which is then utilised in carrying out various life processes and doing our work.
All the living organisms need to respire to get energy from food required for their survival.
All the organisms (plants and animals) require energy for performing various activities and maintaining their life. This energy is obtained by the breakdown of digested food during the process of respiration. The process of releasing energy from food is called respiration.
The process of respiration involves taking in oxygen (of air) into the cells, using it for releasing food, and then eliminating the waste products (carbon dioxide and water) from the body. Oxygen reacts with the food (like glucose) present in the body cells and burns them slowly to release energy. This energy is used by the living organism.
Glucose+ Oxygen ——-> Carbon dioxide + Water + Energy
Respiration is a kind of slow burning (or slow combustion) of food at ordinary temperature to produce energy. The process of respiration is the reverse of photosynthesis. This is because photosynthesis is the making of food (like glucose) by absorbing sunlight energy, whereas respiration is the breaking of food (like glucose) to release energy.
The air which we breathe in is transported to all the parts of the body and ultimately to each cell of the body. In the cells, oxygen brings about the breakdown of glucose. The process of breakdown of food in the cells of the body with the release of energy is called respiration.
Since the process of respiration which releases energy from food takes place inside the cells of the body, it is called cellular respiration.
Aerobic and Anaerobic respiration
The break down of food (like glucose) to release energy can occur in the presence of oxygen as well as in the absence of oxygen.
There are two types of respiration :
1) Aerobic respiration and
2) Anaerobic respiration.
When the breakdown of glucose food occurs with the use of oxygen, it is called aerobic respiration.
In aerobic respiration, the glucose food is completely broken down into carbon dioxide and water with the use of oxygen, and energy is released.
Glucose ————> Carbon dioxide + Water + Energy
The energy released during aerobic respiration is used by the organisms. Most of the living organisms carry out aerobic respiration ( by using oxygen of air).
Most of the plants carry out aerobic respiration by using oxygen of air (to obtain energy).
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.
Glucose ———-> Alcohol + Carbon dioxide + 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 fungus. In yeast, a single cell represents the whole organism. Yeast is used to make alcoholic drinks (such as wine and beer), and bread. Yeast respires anaerobically and during this process, yeast converts glucose into alcohol.
Anaerobic respiration in yeast also produces carbon dioxide gas. In bread-making, the carbon dioxide produced by yeast makes the bread rise. 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.
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.
After a heavy physical exercise (very fast running, etc.), we sometimes get muscle cramps (Painful contractions of muscles are called cramps) . 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. 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 improves 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.
Similarity between aerobic and anaerobic respiration
|Energy is produced by breakdown of food like glucose.
|In this also energy is produced by breakdown of food like glucose.
|It take place in the cells of the organism.
|It also takes place in the cells of the organism.
Difference between aerobic and anaerobic respiration
|It takes place in the presence of oxygen.
|It takes place in the absence of oxygen.
|Complete breakdown of food occurs in this.
|Partial breakdown of food occurs in this.
|The end products are Carbon dioxide, water and energy.
|The end products are alcohol and carbon dioxide or lactic acid.
|It produces large amount of energy.
|It produces less amount of energy.