Water and the Macromolecules

Water's properties all come from one thing

Water is polar and forms hydrogen bonds. Every property follows:

• Cohesion and adhesion — water molecules stick to each other and to surfaces, which is how a $100$ m tree pulls water to its top.
• High specific heat — hydrogen bonds absorb energy before temperature rises, so organisms and lakes resist temperature swings.
• Ice floats — hydrogen bonds lock into an open lattice, so solid water is less dense. Lakes freeze from the top, and life survives underneath.
• Universal solvent for polar and ionic substances.

Four macromolecules

All are built by dehydration synthesis (removing water) and broken by hydrolysis (adding water). The four: carbohydrates, lipids, proteins, nucleic acids. Only lipids are not true polymers.