Water
Biology: Cambridge International GCSE Supplement, topic 3.2.1
Water
Water is a very important solvent (things can be dissolved in it) in living organisms. This means substances can be transported in it, and chemical reactions can take place in it. The chemical symbol for water is H2O; it is made of the elements hydrogen and oxygen.
Transport
- Blood is made mainly of water, with many substances (such as soluble food particles) dissolved in it and transported around the body.
- Waste products such as excess salt are dissolved in urine (which is mainly water), and passed out of the body.
Reactions
- Most human digestive enzymes (proteins that break down large food particles) only work when dissolved in water.
Test yourself on Water
Which of these are true concerning water as a solvent?
What is the chemical formula of water?