Biochemistry: Water and Its Properties

Vocabulary flashcards covering the chemical structure, unique properties, and biological functions of water based on lecture notes.

Body Water Percentage

The human body is made up of approximately $60\%$ \text{H}_2\text{O}, with lung cells containing about $90\%$ \text{H}_2\text{O} and bone cells containing about $22\%$ \text{H}_2\text{O}.

Covalent Bond

A bond involving the sharing of electrons between non-metal atoms, such as the bonds between hydrogen and oxygen in a water molecule.

Inorganic Molecule

A chemical compound that does not contain carbon ($\text{C}$), such as water ($\text{H}_2\text{O}$).

Polar Molecule

A molecule with slightly charged parts resulting from unequal sharing of electrons across its structure.

Hydrogen Bond

A weak attraction formed when the slightly negative oxygen atom of one $\text{H}_2\text{O}$ molecule is attracted to the slightly positive hydrogen atom of another $\text{H}_2\text{O}$ molecule.

High Specific Heat Capacity

A property of water requiring a large amount of energy to increase its temperature, as hydrogen bonds absorb heat.

High Heat of Vaporization

A property of water where hydrogen bonds must be broken before $\text{H}_2\text{O}$ can evaporate.

Universal Solvent

The ability of $\text{H}_2\text{O}$ to dissolve many solutes to create solutions due to its molecular polarity.

Hydrophilic Molecules

Molecules that attract $\text{H}_2\text{O}$ because they are polar or ionize.

Hydrophobic Molecules

Molecules (such as oil) that cannot attract $\text{H}_2\text{O}$ because they are non-polar or nonionized.

Cohesion

The property where $\text{H}_2\text{O}$ molecules stick to each other via hydrogen bonds as they flow, allowing them to pull each other along into a tube.

Adhesion

The property where $\text{H}_2\text{O}$ molecules stick to a polar surface.

Surface Tension

A property where $\text{H}_2\text{O}$ molecules are held together by hydrogen bonds to form a skin-like surface, allowing a basilisk lizard to run on water and causing belly flops to hurt.

Density Difference of Water

A physical property where solid water (ice) is less dense than liquid water, allowing ice to float and preventing bodies of water from freezing solid.

Lubrication

A bodily function of water where fluid acts as a lubricant in joints, saliva, tears, and spinal fluid.

Thermoregulation

A physiological function of water where sweating absorbs heat to help regulate body temperature.

Dehydration Synthesis

A process where $\text{H}_2\text{O}$ is produced when monomers combine to produce polymers.

Hydrolysis

A chemical reaction where $\text{H}_2\text{O}$ is required to convert polymers into monomers.

Buffer

A mechanism in the body where water helps maintain pH levels by combining with $\text{CO}_2$ in the chemical reaction: $\text{CO}_2 + \text{H}_2\text{O} \rightleftharpoons \text{H}_2\text{CO}_3 \rightleftharpoons \text{HCO}_3^- + \text{H}^+$.

Carbonic Acid

The molecule $\text{H}_2\text{CO}_3$ formed when carbon dioxide reacts with water in the body's buffering system.

Bicarbonate

The ion $\text{HCO}_3^-$ produced in the blood buffer reaction to maintain proper pH balance.