Water As A Solvent
- Water is often called the "universal solvent" because it dissolves a wide variety of substances, due to its polarity.
- When polar or charged substances enter water, water molecules surround them, forming hydration shells.
- The δ− oxygen attracts positive charges; the δ+ hydrogens attract negative charges.
- This separates and suspends the particles, keeping them dissolved.
This interaction explains why water dissolves most ionic and polar substances efficiently, making it essential for cellular processes.
What Dissolves In Water
- Hydrophilic ("water-loving") dissolve:
- Polar molecules and charged ions are hydrophilic.
- Dissolves easily in water.
- Eg. Glucose, amino acids, sodium ions (Na⁺), chloride ions (Cl⁻).
- Hydrophobic ("water-fearing") don't dissolve:
- Non-polar molecules are hydrophobic.
- Do not dissolve in water.
- Dissolves in non-polar solvents instead.
- Eg. Fats, oils, cholesterol.
- Hydrophilic substances: Eg. Glucose, amino acids, sodium ions (Na⁺), chloride ions (Cl⁻).
- Hydrophobic substances: Fats, oils, cholesterols
- "Like dissolves like."
- Polar solvents (water) dissolve polar solutes, but not non-polar solutes.
Water's Solvent Properties Make It the Ideal Medium for Metabolism
Definition
Metabolism
The sum of all chemical reactions occurring in an organism to maintain life, including reactions that break down molecules for energy (catabolism) and reactions that build molecules for growth and repair (anabolism).
