Relate the significance of water and inorganic ions (nitrogen, magnesium, calcium and iron) to life.

Water is a transparent, flavourless and unscented chemical substance with chemical formula of H₂O.

1. Solvent

• hydrophilic substances can be dissolved in water due to adhesion force. 
• Water act as a solvent for protein and large organic molecules (carbohydrates) in living cells. Therefore, nutrients can be transported to or within living cells with the elimination of destroying or dissolving nutrients. Further, waste can be also transported out of the living cells

2. Habitat

• the natural home for organisms. 
• Water provide a habitat for aqua-organisms to live in. Numerous organism (fish) rely on water as they cannot survive without water.

3. Metabolite

• the intermediate or resultant in metabolism. 
• Water act as a metabolite in reaction in living cells. In digestion, water break down ingested food which aids the absorption of nutrient. In photosynthesis, glucose and oxygen can be generated by plants from water and carbon dioxide. 

4. Lubricant

• elimination of friction between two surfaces.
• Water act as a lubricant in vertebrate joints as well as alimentary canal. In vertebrate joints, water facilitate the movement of the body. In alimentary canal, water facilities the movement of food

5. ​Support

• maintenance of shape in organisms.
• Water provide support through the provision of a hydrostatic skeleton. For encyclopaedia (earthworms) their skeleton is flexible and supported by the pressure from fluid. Next, Water provide support through the provision of amniotic fluid. Fetus is protected by amniotic fluid and maintain the shape of amniotic sac. Water provide support through the provision of turgor in plant cell. Plant can be rigid and stand up right due to water pressing cell membrane towards cell wall.

6. Transport​​

• delivery of substance throughout living cells.
• Water act as a transport medium in blood plasma and phloem. Therefore, nutrients can be transported into cells while waste can be transported out of cells.

That's all on this topic! 🙌

Written by Bella | HKDSE Biology Specialist @ TUTTEE

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References

1. Thomas, B. & Chris, H. (2013) Hong Kong DSE Biology Critical Guide. Yellowreef Limited.
2. Water. (n.d.). Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Water.