Cellular RespirationCellular respiration is, in its broadest definition, the process in which the chemical bonds of energy-rich molecules such as glucose are converted into energy usable for life processes. All forms of life except viruses carry out respiration. Oxidation of organic material — in a bonfire, for example — releases a large amount of energy rather quickly.
The overall equation for the oxidation of glucose is: C6H12O6 + 6O2 ⇒ 6CO2 + 6H2O + energy Cells with MitochondriaAll eukaryotic cells have mitochondria (Prokaryotic cells don't have mitochondria). Hair cells and outer skin cells are dead cells and no longer actively producing ATP, but all these cells have the same structure. Some cells have more mitochondria than others. Fat cells have many mitochondria because they store a lot of energy. Muscle cells have many mitochondria, which allows them to respond quickly to the need for doing work. Mitochondria occupy 15 to 20 percent of mammalian liver cells.
Cells with no/few mitochondriaSimple organisms like bacteria and archeans belong to a category of life called the prokaryotes. Prokaryotes lack most of the structures found in eukaryotes, including any membrane-bound organelle. This includes a mitochondria, and a nucleus. Since bacteria lack mitochondria, the vast majority of them cannot use oxygen as effectively as eukaryotes.
Most eukaryotes have mitochondria, and all multi-cellular eukaryotes do. However, a few one-celled eukaryotes lack mitochondria. These are usually parasites. Additionally, some multicellular eukaryotes lack mitochondria in specific cells. For example, human red blood cells lack mitochondria, an adaptation that either reduces the cells' size or prevents them from using the oxygen they carry. Cellular Respiration; the reverse of PhotosynthesisThe biggest difference between photosynthesis and respiration is that photosynthesis only occurs in plants and some bacteria while respiration occurs in all living organisms. They do share one big similarity and that is that the process of photosynthesis is actually the same process only it is completed in reverse.
Plants and glucosePlants make their own food by photosynthesis. Carbon dioxide and water react together in the presence of light and chlorophyll to make glucose and oxygen. The glucose is converted into starch, fats and oils for storage. It is used to make cellulose for cell walls, and proteins for growth and repair. It is also used by the plant to release energy by respiration.
Animals on the other hand take part in cellular respiration as outlined above. |
The process of oxidationIn respiration, the process of oxidation is broken down into a large number of steps. These steps are catalysed by enzymes and coenzymes; each step releases a small amount of energy in the form of ATP. This process consists of two main steps: glycolysis, and pyruvate breakdown.
Glycolysis
There are now two ways to break down the resulting pyruvate:
Word EquationCellular Respiration is essentialEnergy is defined as the ability to do work. Cellular respiration provides energy for living organisms. So, cellular respiration is important because it provides the energy for living organisms to perform all of the other necessary functions to maintain life. Most single-celled organisms, such as bacteria, do not require much energy and are able to survive on glycolysis and fermentation. Our ability to think, walk, and talk require enormous amounts of energy which can only be provided by aerobic respiration.
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