Water: The Solvent for Biochemical Reactions

These flashcards cover key vocabulary and concepts from the lecture on water's role as a solvent in biochemical reactions.

Water Planet

Earth is unique as it is an oceanic world, where water's properties support life.

Tetrahedral Structure

In water (H₂O), the oxygen forms a tetrahedral structure with two lone pairs and two hydrogen atoms.

Polar Molecule

A molecule where charge is separated, such as water, leading to dipole formation.

Hydrogen Bond

An attraction between a positively charged hydrogen atom and a negatively charged atom, crucial for water interactions.

Bond Strengths

Refers to the energy required to break bonds, crucial for understanding biochemical interactions.

Osmosis

The spontaneous movement of solvent molecules from an area of lower solute concentration to higher solute concentration.

Hypotonic Solution

A solution with lower solute concentration than the inside of cells, causing cells to swell and possibly rupture.

Isotonic Solution

A solution with equal solute concentration to that inside a cell, resulting in no net water movement.

pH Scale

A logarithmic scale used to define the acidity or basicity of a solution based on hydrogen ion concentration.

Buffer

A solution that can resist pH change upon the addition of small amounts of acid or base.

Colligative Properties

Properties that depend on the number of solute particles in a solution rather than their identity.

Amphipathic Molecule

Molecules that contain both hydrophilic (water-attracting) and hydrophobic (water-repelling) regions.

Dipole-dipole Interaction

Electrostatic interaction between polar molecules which are aligned to maximize attraction.

Heat of Fusion

The amount of energy required to change a solid into a liquid at its melting point.

Hydrophobic Effect

The tendency of nonpolar substances to aggregate in aqueous solutions to minimize contact with water.

Electronegativity

The tendency of an atom to attract electrons, crucial for understanding molecular polarity.

Osmotic Pressure

The pressure required to stop the net flow of water across a semipermeable membrane.

Ion Product of Water (Kw)

The equilibrium constant for the ionization of water, typically expressed as 1 x 10^-14 at 25°C.

Strong Acid

An acid that completely ionizes in solution, releasing H+ ions.

Weak Acid

An acid that does not completely dissociate in solution, thus maintaining a significant fraction of undissociated molecules.

pKa

A measure of the strength of an acid in solution; lower pKa means a stronger acid.