Water: Properties and Biological Functions

Vocabulary flashcards reviewing the seven properties of water, noncovalent biomolecular interactions, reactivity, and role in life functions.

Polarity of Water

The property where the oxygen atom carries a partial negative charge while the two hydrogen atoms carry a partial positive charge, due to oxygen's stronger pull on shared electrons.

Hydrogen Bonding

A weak attraction between the positive hydrogen of one water molecule and the negative oxygen of a neighboring molecule, where each water molecule can form up to four hydrogen bonds.

High Specific Heat Capacity

The property of water requiring a large amount of energy to warm up or cool down because many hydrogen bonds must be broken.

High Heat of Vaporization

The large amount of energy required to convert liquid water into vapor because many hydrogen bonds must be broken.

Cohesion

The attraction between water molecules that produces surface tension.

Adhesion

The attraction between water molecules and other polar surfaces, enabling capillary action.

Universal Solvent

The characteristic of water that allows it to surround and dissolve a wide range of polar and ionic compounds due to its polarity.

Hydration

The process where water's polarity allows it to surround and dissolve other polar and ionic substances.

Density Anomaly

The unique property where water is less dense as a solid than as a liquid because hydrogen bonds arrange ice molecules into a spaced-out lattice structure.

Ionization of Water

The chemical process where water splits into ions according to $\text{H}_2\text{O} \rightleftharpoons \text{H}^+ + \text{OH}^-$, allowing it to act as slightly acidic or slightly basic.

Hydrolysis

A chemical reaction in which water breaks apart bigger molecules into smaller ones by adding $\text{H}$ and $\text{OH}$ across a bond.

Dehydration Synthesis

A reaction where cells remove water to join small molecules together into bigger ones, such as building proteins and DNA.

Ionic Interactions

Electrostatic attractions between oppositely charged groups involving the transfer and gaining of electrons.

Van der Waals Forces

Very weak, short-range attractions caused by temporary shifts in electron distribution around atoms.

Hydrophilic

Water-loving polar substances that readily form hydrogen bonds and dissolve in water.

Hydrophobic

Water-fearing nonpolar substances, such as oils and fats, that do not readily form hydrogen bonds and will not dissolve in water.

$\pi-\pi$ Stacking

An attraction between ring-shaped structures (aromatic rings) that allows them to stack on top of one another.

Capillary Action

The movement of water against gravity in plants enabled by the combined forces of cohesion and adhesion.

Turgor Pressure

The pressure created by water inside plant cells that gives them their structural shape.

pH Balance

The biological regulation governed by water's ability to ionize into $\text{H}^+$ and $\text{OH}^-$ ions, which affects enzyme and protein function in living systems.