The Chemistry of Life - Vocabulary Flashcards

Vocabulary practice flashcards covering basic atomic structure, chemical bonding, properties of water, macromolecular reactions, functional groups, carbohydrates, and nucleic acid chemistry.

Element

A substance composed of one type of atom, determined by the number of protons in its nucleus.

Dalton (Da)

A unit of mass equal to $1.7 \times 10^{-24}\,g$, used as a measure for subatomic particles like protons and neutrons.

Atomic Number

The number of protons contained in an atom's nucleus, which uniquely identifies an element.

Mass Number

The total number of protons and neutrons in a single atom.

Atomic Weight

The average of the mass numbers of a representative sample of atoms of an element.

Isotopes

Forms of an element that have the same number of protons but different numbers of neutrons (e.g., hydrogen, deuterium, and tritium).

Orbitals

3D regions within electron shells where an electron is found at least $90\%$ of the time.

Valence Shell

The outermost electron shell of an atom containing valence electrons that determine chemical reactivity and bonding capability.

Chemical Bond

An attractive force that links atoms together to form molecules.

Octet Rule

The tendency of atoms to form stable molecules resulting in full valence shells.

Covalent Bond

A strong chemical bond formed when two atoms share one or more pairs of electrons to fill their outer shells, possessing a bond energy of $50\text{--}110$.

Chemical Bond Types and Energies

A comparison table summarizing various chemical interactions, their foundational bases, structural representations, and bond energies.

Electronegativity

The extent of attractive force that an atomic nucleus exerts on electrons in its electron shells.

Electronegativity Values of Elements

Relative electronegativity scale for major biological elements, ranging from Oxygen ($3.5$) down to Potassium ($0.8$).

Nonpolar Covalent Bond

A covalent bond where bonding electrons are shared equally between two atoms with similar electronegativity values (difference $\le 0.4$).

Polar Covalent Bond

A covalent bond where bonding electrons are shared unequally because one atom has greater electronegativity, creating partial charges.

Ionic Bond Interaction Structure

A bond formed by the electrical attraction of opposite charges following a complete transfer of electrons, showing bond energy of $3\text{--}7$.

Ions

Electrically charged particles formed when an atom loses or gains one or more electrons.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Hydrogen Bond

An electrical attraction between a covalently bonded $\delta^+$ hydrogen atom and a $\delta^-$ electronegative atom, with a bond energy of $3\text{--}7$.

Heat of Vaporization

The amount of heat energy a liquid absorbs in order to transform into a gaseous state.

Cohesion

The attraction between water molecules created by hydrogen bonding that causes them to stick together, producing surface tension.

Hydrophilic

Polar molecules that readily form hydrogen bonds with water and dissolve freely in aqueous solutions.

Hydrophobic

Nonpolar molecules that cannot form hydrogen bonds with water and do not dissolve in aqueous solutions.

pH

The negative logarithm of the hydrogen ion concentration in a solution, expressed as $\text{pH} = -\log[\text{H}^+]$.

Acids

Substances that release hydrogen ions ($\text{H}^+$) when dissolved in water, increasing proton concentration and lowering pH.

Bases

Substances that accept hydrogen ions ($\text{H}^+$) in water, reducing proton concentration and raising pH.

Buffer

A mixture of a weak acid and its corresponding base that minimizes changes in pH when small amounts of acid or base are added.

Functional Groups in Biological Macromolecules

Combinations of atoms with distinct chemical properties (such as Hydroxyl, Aldehyde, Keto, Carboxyl, Amino, Phosphate, Sulfhydryl, and Methyl) that dictate macromolecular function.

Condensation Reaction

A chemical reaction that links monomers together via covalent bonds to form polymers, releasing a molecule of water ($\text{H}_2\text{O}$).

Hydrolysis Reaction

A chemical reaction that breaks covalent bonds between monomers within a polymer through the addition/consumption of a water molecule ($\text{H}_2\text{O}$).

Monosaccharides

The simple sugar monomer units of carbohydrates.

Structural Isomers

Molecules that share the exact same chemical formula (e.g., hexoses with $\text{C}_6\text{H}_{12}\text{O}_6$) but differ in the arrangement and connectivity of their atoms.

Glycosidic Bonds

Covalent bonds that link monosaccharides together to form di-, oligo-, and polysaccharides.

Nucleic Acids

Informational macromolecular polymers (DNA and RNA) specialized for the storage, transmission, and expression of genetic information.

Nucleotides

The monomer building blocks of nucleic acids, consisting of a nitrogenous base, a five-carbon pentose sugar, and a phosphate group.

Nucleosides

Molecules consisting solely of a nitrogenous base attached to a five-carbon sugar, lacking a phosphate group.

Pyramidines

Single-ring nitrogenous bases, comprising cytosine (C), uracil (U), and thymine (T).

Purines

Fused double-ring nitrogenous bases, comprising adenine (A) and guanine (G).

Phosphodiester Bond

A covalent linkage connecting adjacent nucleotides in a nucleic acid strand by joining the 3' carbon of one pentose sugar to the 5' carbon of the next via a phosphate group.

Complementary DNA Sequence

The antiparallel strand sequence pairing with 5'-ATCAGG-3', which is 3'-TAGTCC-5' joined by hydrogen bonds between complementary bases.

Chargaff's Rule

The principle stating that in any sample of double-stranded DNA, the percentage of adenine equals thymine ($\%\text{A} = \%\text{T}$) and the percentage of guanine equals cytosine ($\%\text{G} = \%\text{C}$).