Chapter 2: Chemical Principles - Vocabulary Flashcards

Vocabulary practice flashcards covering atomic structure, chemical bonding, biological functional groups, and major macromolecule classes from Chapter 2.

Matter

Anything that takes up space and has a mass.

Atom

The smallest unit of matter.

Electrons

Negatively charged subatomic particles in an atom.

Protons

Positively charged subatomic particles located in the nucleus of an atom.

Neutrons

Uncharged subatomic particles located in the nucleus of an atom.

Element

A substance composed of a single type of atom.

Atomic number

The number of protons in the nucleus, which is unique for each element.

Atomic mass

The sum of the masses of protons, neutrons, and electrons in an atom.

Isotopes

Atoms of the same element that have different neutron counts.

Valence electrons

Electrons located in the outermost shell of an atom that interact with other atoms.

Valence

The number of missing or extra electrons in the outermost shell of an atom.

Chemical bonds

Attractive forces that act between atoms when they share or transfer their valence electrons.

Molecule

Two or more atoms held together by chemical bonds.

Compound

A molecule composed of more than one element.

Electronegativity

The power of an atom to attract electrons in a chemical bond.

Nonpolar covalent bond

A bond where shared electrons spend an equal amount of time around each nucleus between atoms with similar electronegativity.

Polar covalent bond

A bond where electrons are shared unequally between atoms with significantly different electronegativities, forming partial charges or poles.

Ionic bond

A bond formed by the electrostatic attraction between positively charged cations and negatively charged anions.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons.

Hydrogen bond

An intermolecular force formed when a hydrogen atom covalently bonded to an $O$ or $N$ atom is attracted to another $N$ or $O$ atom.

Organic compounds

Chemical compounds that always contain carbon and hydrogen.

Inorganic compounds

Chemical compounds that typically lack carbon.

pH

A logarithmic measure of the hydrogen ion concentration in a solution, defined as $pH = -\log[H^+]$.

Carbon skeleton

The chain of carbon atoms that forms the basic structure of an organic molecule.

Functional groups

Specific combinations of atoms responsible for most of the characteristic chemical properties of an organic compound.

Monomers

Small organic molecules that serve as structural building blocks for larger molecules.

Macromolecules

Large polymer molecules consisting of many repeating monomer units.

Dehydration synthesis

A chemical reaction (also called condensation reaction) that joins monomer units together by removing a molecule of water.

Hydrolysis

A chemical reaction that breaks down polymers into smaller units by adding water.

Carbohydrates

Organic molecules composed of carbon, hydrogen, and oxygen with the formula $(CH_2O)_n$.

Monosaccharides

Simple sugars containing 3 to 7 carbon atoms, such as glucose, fructose, and galactose.

Disaccharides

Carbohydrates formed when two monosaccharides are joined through a dehydration synthesis reaction.

Polysaccharides

Complex carbohydrates consisting of tens to hundreds of covalently bonded monosaccharides.

Glycosidic bond

The covalent linking bond that holds monosaccharide units together in carbohydrates.

Proteins

Biological macromolecules composed of $C$, $H$, $O$, $N$, and sometimes $S$, built from amino acid monomers.

Amino acids

The monomer units of proteins, consisting of a central carbon bonded to an amino group, carboxyl group, hydrogen atom, and a variable side group ($R$).

Stereoisomers

Molecules made of the same atoms bonded in the same sequence but differing in 3D arrangement as non-superimposable mirror images.

Peptide bond

The covalent bond formed between amino acids during dehydration synthesis to construct polypeptides.

Primary structure

The linear sequence of amino acids forming a polypeptide chain.

Secondary structure

The localized coiling into an $\alpha$-helix or folding into $\beta$-pleated sheets in a polypeptide, stabilized by hydrogen bonds between backbone atoms.

Tertiary structure

The overall 3D folding pattern of a single polypeptide chain formed by interactions between the $R$ groups of amino acids.

Quaternary structure

The structural arrangement consisting of two or more folded polypeptide chains associated together.

Denaturation

A process that causes a protein to lose its 3D structure and biological function due to conditions like heat, acids, bases, or harsh chemicals.

Enzymes

Biological catalysts, almost always proteins, that accelerate chemical reactions by binding specific substrates.

Active site

The specific region on an enzyme where a substrate binds to undergo a chemical reaction.

Lipids

Nonpolar, hydrophobic organic molecules composed of $C$, $H$, and $O$ that are not constructed from regular repeating monomers.

Ester bond

The covalent linking bond formed between glycerol and fatty acids in lipid molecules.

Saturated fatty acid

A fatty acid with a hydrocarbon tail containing no double bonds, saturated with the maximum number of hydrogen atoms.

Unsaturated fatty acid

A fatty acid whose hydrocarbon tail contains one or more double bonds.

Phospholipids

Lipids composed of a hydrophilic polar head (glycerol, organic, and phosphate groups) and nonpolar hydrophobic tails (fatty acids).

Steroids

Lipids characterized by a multi-ring carbon structure, including membrane sterols like cholesterol and ergosterol.

Nucleic acids

Macromolecules (DNA and RNA) composed of nucleotide monomers that carry genetic instructions and function in protein synthesis.

Nucleotides

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

Phosphodiester bond

The covalent bond that links adjacent nucleotides in a nucleic acid chain.

DNA

A double-stranded nucleic acid containing deoxyribose sugar and thymine that carries genetic material in living organisms.

RNA

A single-stranded nucleic acid containing ribose sugar and uracil that functions in protein synthesis.

Purines

Double-ring nitrogenous bases, specifically adenine ($A$) and guanine ($G$), found in nucleic acids.

Pyrimidines

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