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Respiration is a characteristic of a living thing.
Definition: It is the process by which food particles (such as carbohydrates) are broken down to produce energy.
It is a catabolic process which results in the loss of dry mass (as substances are liberated).
Carbon dioxide along with *water, *ethanol or *lactic acid may be produced.
Adenosine-triphosphate molecules ie ATP are formed during respiration. Energy is temporarily stored in these & can be released whenever it's required.
Energy is needed for many important things:
• Growth & repair, heartbeat, transmission of nerve impulses, movement, active transport, muscular contraction, protein synthesis, all this requires energy.
These respiratory processes produce heat (exothermic), thereby maintaining body temperature.
*On the other hand, photosynthesis takes in light energy from the sun, carbon dioxide and water along with other mineral ions in the presence of chlorophyll to build carbohydrates. It's an endothermic process.*
There are 2 types of respiration namely, aerobic respiration & anaerobic respiration.
• AEROBIC RESPIRATION- 1) It occurs in the presence of oxygen. 2) It releases a large amount of energy. (3000KJ approx) 3) It occurs in the mitochondria of cells.
Word equation: glucose + oxygen-> carbon dioxide + water + energy
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•ANAEROBIC RESPIRATION- 1) It occurs in the absence of oxygen. 2) It releases a small amount of energy. (150KJ during lactate fermentation & 210KJ during fermentation) *fermentation generally means 'giving off of effervescence' but in terms of biology it is when alcohol is formed by anaerobic respiration by yeast/plants. 3) It occurs in the cytoplasm of the cell.
In the case of anaerobic respiration, glucose aided by enzymes, is broken down in the absence of oxygen to produce carbon dioxide and lactic acid/alcohol.
Yeast can respire both aerobically and anaerobically. When it performs anaerobic respiration, glucose is broken down to produce alcohol, carbon dioxide and energy. It's a process known as fermentation. Glucose -> alcohol + carbon dioxide + energy
