Mitochondria are tiny thailantour.comanelles inside cells that are involved in releasing energy from food.
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This process is known as cellular respiration. It is for this reason that mitochondria are often referred to lớn as the powerhouses of the cell. Cells that need a lot of energy, like muscle cells, can contain thousands of mitochondria.
Apart from cellular respiration, mitochondria also play a key role in the ageing process as well as in the onset of degenerative disease.
The powerhouse function
When the breakdown products from the digestion of food find their way into the cell, a series of chemical reactions occur in the cytoplasm. This allows some of the energy locked up in these products to be released và incorporated into the universal energy supplier in cells known as ATP (adenosine triphosphate).
Remaining molecular fragments from this process then enter the mitochondria, & in a complex series of steps, they are finally converted into carbon dioxide và water. The energy locked up in these fragments is incorporated into more ATP.
The ATP molecules produced in this way can then be used by the cell to lớn supply the energy needed khổng lồ function. ATP → ADP + p. + energy khổng lồ function.
The overall chemical reaction that occurs when glucose is broken down is:
C6H12O6 glucose | + | 6O2 oxygen | → | 6CO2 carbon dioxide | + | 6H2O water | + | energy in the size of ATP molecules |
It has been estimated that, in an average person, the turnover rate (the rate at which ATP is produced and consumed) is a massive 65 kilogam per day.
The human body toàn thân is a fantastically energetic machine. It has been estimated that, kilogram for kilogram, the human body, when sitting comfortably, is converting 10,000 times more energy than the Sun in every second!
Free radicals: a byproduct of respiration
During cellular respiration, highly reactive molecules called không tính tiền radicals are formed within mitochondria. Perhaps the best known free radical produced in this way is the superoxide radical, O2-.
Free radicals are potentially very damaging lớn cell components such as proteins and genetic material lượt thích DNA và RNA. If too many không tính phí radicals are released in the mitochondria, the damage can be severe, resulting ultimately in the death of the cell. Lớn protect against không tính phí radical damage, mitochondria produce their own antioxidant enzymes. One such enzyme is known as superoxide dismutase or SOD.
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Although free radicals are damaging, they have an important signalling role. Scientists now believe that mitochondria operate a sensitive feedback mechanism in which some of the free radicals themselves act as signals lớn the cell, causing it to calibrate & adjust cellular respiration, so to lớn remove them completely is not good for the cell.
Antioxidants in mitochondria
Chemicals present in some fruits & vegetables have been shown to lớn have antioxidant activity. This means that, in laboratory tests, they can neutralise không lấy phí radicals. It was thought that consuming these foods, or extracts made from them, would help the body to remove damaging không tính tiền radicals.
Recent research suggests that antioxidants work differently in the body than in the laboratory. It is now thought that some antioxidants, in particular, a class of plant chemicals known as polyphenols, have a direct effect on the mitochondria. It appears that they stimulate the mitochondria khổng lồ become more efficient in generating energy from food, so they generate fewer free radicals và neutralise them more quickly. It is as if the functioning of the mitochondria is being ‘tuned up’ by these polyphenols – an effect similar to lớn that induced in the mitochondria by exercise.
Find out more about Antioxidants.
Maintaining healthy mitochondria
If mitochondria are not functioning efficiently, their energy-producing capacity is reduced, more miễn phí radicals escape causing damage lớn the cell and early cell death may follow.
Research over recent years is indicating that the health of mitochondria is very much lifestyle & diet dependent. Excessive consumption of sugary foods & beverages reduces mitochondrial efficiency. Lack of exercise reduces the number of mitochondria in active cells such as muscle, và they become inefficient, leaking out more miễn phí radicals into the cell.
By choosing a lifestyle that includes regular exercise, daily consumption of fresh fruits và vegetables, avoidance of sugary foods, control of appetite and avoiding smoking, anyone can tune up their mitochondria, which should help khổng lồ promote a long & very healthy life.
Nature of science
One of the habits of scientists is open-mindedness. Scientists need to lớn be receptive to lớn new ideas and suggestions. As new evidence is discovered, new ways of interpreting and understanding it may have lớn be considered.