Properties of Water, pH, Acids, Bases, and Biological Macromolecules

Vocabulary practice flashcards covering water properties, solution chemistry, pH, buffers, carbohydrates, and lipids based on lecture notes.

Solution

A uniform mixture of two or more substances.

Solute

The dissolved substance in a solution.

Solvent

The liquid in which solutes are distributed.

Aqueous solution

A solution in which water is the solvent.

Heat capacity

The quantity of heat required to raise the temperature of a unit mass of a substance by $1\,^\circ\text{C}$.

Thermal inertia

The property of water changing temperature slowly due to its unusually high heat capacity.

Dissociation

The process in which inorganic compounds held together by ionic bonds split into smaller molecules or ions in water.

Ionization

The dissociation of ionic compounds into ions in solution.

Hydration sphere

A sheath formed by polar water molecules around ions and small polar molecules to keep them in solution.

Electrolytes

Soluble inorganic substances whose ions conduct electricity in solution.

Hydrophilic

Molecules or compounds that interact readily with water, including ions and polar molecules.

Hydrophobic

Molecules or compounds that do not interact readily with water, including nonpolar molecules, fats, and oils.

Colloid

A solution containing dispersed proteins or other large molecules that remain mixed throughout the liquid (e.g., blood plasma).

Suspension

A mixture containing large particles in solution that will settle out if left undisturbed (e.g., whole blood).

pH

The negative logarithm of the hydrogen ion ($\text{H}^+$) concentration of a solution measured in moles per liter.

Neutral pH

A condition with equal numbers of $\text{H}^+$ and $\text{OH}^-$ ions, represented by a pH of $7.0$ in pure water.

pH Scale

A logarithmic scale representing hydrogen ion concentration, where a change of one unit corresponds to a 10-fold change in $\text{H}^+$ concentration.

Acid

A solute functioning as a proton donor that adds hydrogen ions to a solution.

Base

A solute functioning as a proton acceptor that removes hydrogen ions from a solution.

Strong acid

An acid that dissociates completely in solution (e.g., $\text{HCl}$).

Weak acid

An acid that does not dissociate completely in solution (e.g., $\text{H}_2\text{CO}_3$).

Salt

An ionic compound that dissociates in water into cations and anions other than hydrogen ions ($\text{H}^+$) and hydroxide ions ($\text{OH}^-$).

Buffers

Compounds or systems that stabilize the pH of solutions by neutralizing added acids or bases.

Monomers

Identical subunits that can join together to form larger complex molecules called polymers.

Polymers

Large macromolecules formed by joining identical subunits (monomers) together through dehydration synthesis.

Dehydration synthesis

A chemical reaction that joins monomers together to form larger molecules by removing a water molecule.

Hydrolysis

A chemical process that breaks down complex molecules into smaller units by adding a water molecule.

Functional groups

Groupings of atoms within organic compounds that influence the physical and chemical properties of those compounds.

Carbohydrates

Organic macromolecules containing carbon, hydrogen, and oxygen in a $1:2:1$ ratio that serve as a primary energy source.

Monosaccharides

Simple sugars containing three to seven carbon atoms that are hydrophilic and serve as carbohydrate building blocks.

Glucose

The most important metabolic fuel in the human body.

Isomers

Molecules that share the same molecular formula but have different structural arrangements (e.g., glucose and fructose).

Disaccharides

Complex sugars formed when two monosaccharides are joined together by dehydration synthesis (e.g., sucrose).

Polysaccharides

Complex carbohydrates formed by joining many monosaccharides together through dehydration synthesis.

Glycogen

A long, branching chain polysaccharide of glucose molecules that serves as the main storage carbohydrate in animal liver and muscle cells.

Lipids

Mainly hydrophobic organic macromolecules containing carbon and hydrogen in a $1:2$ ratio with relatively little oxygen.

Fatty acids

Long chains of carbon and hydrogen with a polar carboxyl group ($\text{-COOH}$) at one end that serve as lipid monomers.

Saturated fatty acid

A fatty acid with no double bonds in its hydrocarbon tail, containing the maximum possible number of hydrogen atoms.

Unsaturated fatty acid

A fatty acid containing one or more double bonds in its hydrocarbon tail.

Triglycerides

Lipids consisting of a glycerol molecule attached to three fatty acids; serve as energy reserves, insulation, and organ protection.

Steroids

Large lipid molecules characterized by a distinct four-ring carbon structure (e.g., cholesterol, estrogen, testosterone).