General Chemistry and Biological Molecules Study Guide

Comprehensive vocabulary flashcards reviewing general chemistry principles, atomic structure, chemical reactions, acids, bases, buffers, and major biological macromolecules.

Element

A pure chemical substance consisting of only one type of atom that cannot be broken down into simpler substances by chemical reactions.

Atom

The basic structural and functional unit of matter that retains all the chemical properties of an element, composed of protons, neutrons, and electrons.

Atomic Number

The total number of protons located within the nucleus of an atom, defining the identity of an element (such as an atomic number of $6$ for Carbon).

Atomic Weight (Atomic Mass)

The average mass of an atom of a given element, measured in atomic mass units, reflecting the weighted average of its naturally occurring isotopes (e.g., $12.011$ for Carbon).

Periodic Table Entry for Carbon

The standard tile format displaying the atomic number ($6$), element name (Carbon), chemical symbol ($\text{C}$), and atomic mass ($12.011$).

Atom Diagram Components (A, B, and C)

$\text{A}$ indicates an electron orbiting within an electron shell; $\text{B}$ and $\text{C}$ designate the subatomic particles (protons and neutrons) clustered in the central atomic nucleus.

Rule for Diagramming an Atom (Electron Shell Rule)

The principle governing electron configuration stating that the first energy shell holds a maximum of $2$ electrons, while subsequent outer shells can accommodate up to $8$ electrons to achieve chemical stability.

Isotopes

Variants of a particular chemical element that possess the exact same number of protons but differ in their number of neutrons, leading to different atomic mass numbers.

Carbon-12, Carbon-13, and Carbon-14 ($C_{12}$, $C_{13}$, and $C_{14}$)

Three distinct isotopes of carbon that each share $6$ protons: $C_{12}$ has $6$ neutrons, $C_{13}$ has $7$ neutrons, and $C_{14}$ has $8$ neutrons.

Radioisotope

An unstable isotope with an unstable nucleus that undergoes spontaneous radioactive decay, emitting energy and particles to reach a more stable atomic state.

Ion

An atom or chemical group that has gained or lost one or more electrons, acquiring an overall net positive (cation) or negative (anion) electrical charge.

Ionic Reaction

A chemical interaction involving the complete transfer of valence electrons from one atom to another, generating oppositely charged ions that attract into an ionic bond.

Covalent Reaction

A chemical reaction in which two atoms share one or more pairs of valence electrons to complete their respective electron shells.

Molecule

An electrically neutral group of two or more atoms held firmly together by covalent chemical bonds.

Polar Covalent Bond

A type of covalent bond where electrons are shared unequally between atoms of differing electronegativity, establishing partial positive ($\delta^+$) and partial negative ($\delta^-$) charges.

Hydrogen Bond

A weak, attractive intermolecular or intramolecular force between a partially positive hydrogen atom and a strongly electronegative atom (such as oxygen or nitrogen).

Inorganic Molecules

Chemical substances that typically lack carbon-hydrogen bonds, including water ($H_2O$), oxygen ($O_2$), carbon dioxide ($CO_2$), mineral salts, acids, and bases.

Acid

A substance that dissociates in an aqueous solution to release hydrogen ions ($H^+$), yielding a $pH$ value strictly below $7$.

Base

A substance that either binds to hydrogen ions ($H^+$) or dissociates to release hydroxide ions ($OH^-$), yielding a $pH$ value strictly above $7$.

Salt

An ionic compound formed from the neutralization reaction between an acid and a base, dissociating in water into cations other than $H^+$ and anions other than $OH^-$ (e.g., $NaCl$).

pH

A logarithmic measurement of the concentration of free hydrogen ions in a solution, mathematically defined as $pH = -\log_{10}[H^+]$, where values range from acidic ($< 7$), to neutral ($7$), to basic ($> 7$).

Buffer

A chemical system composed of a weak acid and its corresponding conjugate base that maintains stability by resisting significant shifts in $pH$ upon the addition of small amounts of acid or base.

Functional Groups

Specific clusters of atoms attached to carbon skeletons in organic molecules that confer distinct chemical properties and reactivity (e.g., hydroxyl, carboxyl, amino, and phosphate groups).

Dehydration Synthesis

A condensation reaction that chemically bonds two monomer subunits into a larger polymer through the covalent removal of a water molecule ($H_2O$).

Hydrolysis

A chemical cleavage process that breaks down covalent bonds within complex polymers into simpler monomer units through the addition of a water molecule ($H_2O$).

Carbohydrates

Organic macromolecules functioning primarily as rapid energy sources and structural support, classified into monosaccharides (e.g., glucose), disaccharides (e.g., sucrose), and polysaccharides (e.g., glycogen, starch, cellulose).

Lipids

A diverse class of hydrophobic, nonpolar organic molecules divided into triglycerides (energy storage fats/oils), phospholipids (bilayer membrane components), and steroids (four-ring lipid structures including cholesterol).

Proteins

Macromolecules consisting of linear chains of amino acid monomers joined by peptide bonds, serving structural, catalytic, transport, regulatory, and defensive roles.

Four Levels of Protein Structure

The organizational hierarchy of proteins comprising primary structure (linear amino acid sequence), secondary structure ($\alpha$-helices and $\beta$-pleated sheets), tertiary structure (3D folding), and quaternary structure (multimeric polypeptide assemblies).

Enzyme

A biological catalyst, typically a protein, that accelerates the velocity of specific chemical reactions by lowering the required activation energy without being permanently altered or consumed.

Nucleotide

The monomer building block of nucleic acids, structurally assembled from three linked parts: a five-carbon pentose sugar, a negatively charged phosphate group, and a nitrogenous base.

Nitrogenous Bases in DNA and RNA

The heterocyclic nitrogen-containing bases: DNA incorporates Adenine ($\text{A}$), Thymine ($\text{T}$), Cytosine ($\text{C}$), and Guanine ($\text{G}$); RNA incorporates Adenine ($\text{A}$), Uracil ($\text{U}$), Cytosine ($\text{C}$), and Guanine ($\text{G}$).

Adenosine Triphosphate (ATP)

An essential cellular nucleotide composed of the base adenine, a ribose sugar, and three phosphate groups, acting as the primary chemical energy currency within living systems.