A1.1 Water - Unity and Diversity

This set of vocabulary flashcards covers the chemical, physical, and biological properties of water, including its role as a solvent, cohesive and adhesive forces, and its extraterrestrial origins.

Water

A polar molecule that serves as an excellent solvent for the vast majority of elements and compounds necessary for life, and was the medium in which the first cells evolved.

Viscosity

A physical property of water that is relatively high compared to air, meaning aquatic organisms must adapt their body shape and propulsion to move easily.

Enzymes

Biological molecules that increase the rate of chemical reactions and must be dissolved in water to function properly.

Covalent bond

The bond between a hydrogen atom and an oxygen atom in water that involves the unequal sharing of electrons.

Polarity

A feature of a molecule where it has two poles; in water, the hydrogen atoms have a positive charge and the oxygen atom has a negative charge.

Hydrogen bond

The attraction between water molecules resulting from the polar covalent bonds within the molecules.

Cohesion

The property where water molecules tend to stick together due to hydrogen bonding, allowing water to be drawn up xylem vessels in plants.

Surface tension

A property where outermost water molecules form stronger attractive forces with neighbors below them, allowing water to form nearly spherical droplets.

Adhesion

The property of water molecules tending to stick to other substances or materials that are polar or charged.

Hydrophilic

A term describing materials and substances with an affinity for water; examples include glucose, ions, amino acids, and proteins.

Capillary action

The process demonstrated when water adheres strongly to surfaces and is drawn up narrow tubes, such as plant xylem, without the column breaking.

Solvent

A medium, such as water, that surrounds cations and anions (like $Na^-$ and $CI^-$) with a layer of orientated molecules to dissolve them.

Organic molecules

Carbon-containing molecules that can dissolve in water if they have ionized groups (like the carboxyl group $-COO^-$ and amino group $-NH/$) or hydroxyl groups ($-OH$).

Hydrophobic

A term describing non-polar substances that are repelled by water; examples include oil, phospholipid tails, testosterone, and some proteins.

Asteroids

The limited hypothesis source for the origin of water on Earth.

Goldilocks zone

The region in space used in the search for extraterrestrial life where temperatures are low enough to condense water.