Water
Properties of Water
- Water is a polar molecule due to the presence of polar covalent bonds between hydrogen and oxygen atoms.
- Owing to its polarity, water is an excellent solvent for many substances including sugars, ions and some proteins.
- The hydrogen bonding in water contributes to its high specific heat capacity, meaning it can absorb or release a great deal of heat without changing much in temperature.
- It also has high latent heat of vaporisation, making it effective for cooling organisms.
Role of Water in Cells and Organisms
- Water forms the main component of cells (around 70-95%) and is crucial for many biological processes.
- It is essential for transportation of nutrients, gases, and waste materials within the body.
- Water provides a medium for metabolic reactions to take place on in cells.
- It serves as a reactant in many biochemical reactions such as hydrolysis and photosynthesis.
Water in Homeostasis
- The high heat capacity of water enables it to play a vital role in temperature regulation in organisms.
- It aids in maintaining the volume and pressure in cells and the whole organism. An example is osmoregulation in kidneys.
- Water helps in maintaining pH balance as it can act as both an acid (donating H+ ions) and a base (accepting H+ ions).
Water Cycle in Ecosystems
- The constant circulation of water in the environment, known as the water cycle, is crucial for life on earth.
- It includes processes such as evaporation, condensation, and precipitation, which contribute to the distribution and availability of water for different organisms.
- This cycle indirectly supports various favourite metabolic pathways such as photosynthesis in plants.