... yet they require oxygen to respire, and as water is such a good solvent the required oxygen gas is dissolved in the water. Water is the most abundant component in any organism, the lowest is 20% in seeds, while jellyfish are 99% (hence the transparency). It plays vital roles in the metabolism of all cells and in photosynthesis (providing raw materials) in plant cells. In all cells water is used for; hydrolysis, the breakdown of a substance by water, e.g. polysaccharides to monosaccharides, forming a glycosidic bond; a medium for chemical reactions, due to its properties as a solvent; the diffusion and osmosis of substances, e.g. gaseous exchange, which need to be moist as the exchange takes place in solution, therefore there is water in the lungs or in mesophyll cells in plants. It is also used on a much larger scale for transport. Blood is mostly water, ...

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