BIO 181 Key Vocabulary: Chemistry of Life, Biomolecules, and Proteins

Vocabulary flashcards covering atomic structure, chemical bonding, electronegativity, nucleic acids, carbohydrates, lipids, protein structure/function, enzymes, and active learning concepts from BIO 181.

Atom

The smallest unit of matter, consisting of a nucleus containing protons ($+\text{charge}$) and neutrons ($0\text{ charge}$), surrounded by electron shells containing electrons ($-\text{charge}$).

Atomic Number

The total number of protons in an atom's nucleus.

Mass Number

The combined total number of protons and neutrons in an atom's nucleus.

Valence Electrons

Electrons residing in the outermost electron shell of an atom, which determine its chemical stability and bonding capacity.

Electronegativity

The measure of an atom's tendency or power to attract electrons toward itself in a chemical bond.

Nonpolar Covalent Bond

A covalent bond formed by the equal sharing of electrons between two atoms with an electronegativity difference between $0$ and $0.4$.

Polar Covalent Bond

A covalent bond formed by the unequal sharing of electrons between atoms with an electronegativity difference greater than $0.4$ and less than $1.8$, producing partial positive ($\delta^+$) and partial negative ($\delta^-$) charges.

Ionic Bond

A chemical bond formed by the complete transfer of one or more valence electrons from one atom to another, occurring between atoms with an electronegativity difference of $\ge 1.8$ and producing full charges.

Hydrogen Bond

An attraction between the partial positive charge ($\delta^+$) of a hydrogen atom in a polar molecule and the partial negative charge ($\delta^-$) of an electronegative atom (such as oxygen or nitrogen) in another molecule.

Hydrophilic Molecules

Water-loving molecules that are polar or charged and readily dissolve in water.

Hydrophobic Molecules

Water-fearing molecules that are nonpolar and do not dissolve in water.

Monomer

A small, single molecular subunit ("one part") that can chemically bond with other subunits to form a polymer.

Polymer

A large macromolecule composed of many repeating monomer subunits joined together by chemical bonds.

Monosaccharides

The monomer building blocks of carbohydrates, characterized by carbon chains or rings containing hydroxyl ($-OH$) groups and a carbonyl ($C=O$) group (e.g., glucose, fructose, galactose).

Polysaccharides

Large carbohydrate polymers formed by linking monosaccharides together, functioning in energy storage (e.g., starch in plants, glycogen in animals) or structural support (e.g., cellulose in plants).

Nucleotides

The monomer subunits of nucleic acids, each consisting of a phosphate group, a five-carbon sugar (ribose or deoxyribose), and a nitrogenous base.

Pyrimidine Bases

Single-ring nitrogenous bases found in nucleic acids, including Cytosine ($C$), Thymine ($T$), and Uracil ($U$).

Purine Bases

Double-ring nitrogenous bases found in nucleic acids, including Guanine ($G$) and Adenine ($A$).

Phosphodiester Bond

The covalent bond that links the phosphate group of one nucleotide to the sugar of another nucleotide along a nucleic acid chain.

Triacylglycerol

A lipid molecule consisting of a glycerol molecule linked to three fatty acid chains, serving as a primary form of energy storage in fat cells.

Phospholipid

An amphipathic lipid consisting of a hydrophilic phosphate head and two hydrophobic fatty acid tails, forming the primary structure of cell membranes.

Unsaturated Fatty Acid

A fatty acid chain that contains at least one carbon-carbon double bond ($C=C$), introducing a kink into the hydrocarbon chain.

Saturated Fatty Acid

A fatty acid chain with no carbon-carbon double bonds, fully saturated with hydrogen atoms.

Van der Waals Forces

Weak noncovalent interactions between nonpolar hydrocarbon chains or molecules placed in close proximity.

Amino Acids

The monomer units of proteins, each containing a central carbon atom bonded to an amino group ($H_2N$ or $H_3N^+$), a carboxyl group ($COOH$ or $COO^-$), a hydrogen atom, and a variable side chain (R-group).

Peptide Bond

The covalent bond formed between the carboxyl group of one amino acid and the amino group of an adjacent amino acid.

Primary Structure

The linear sequence of amino acids in a polypeptide chain connected by peptide bonds.

Secondary Structure

Local spatial structures within a polypeptide chain, such as $\alpha$-helices and $\beta$-pleated sheets, stabilized by hydrogen bonds along the peptide backbone.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain, maintained by interactions between side chains (R-groups), including hydrogen bonds, ionic bonds, hydrophobic interactions, van der Waals forces, and disulfide bonds.

Quaternary Structure

The overall protein structure formed when two or more individual polypeptide chains assemble into a functional complex.

Enzyme

A specialized protein that acts as a biological catalyst to accelerate chemical reactions by lowering activation energy without being consumed in the reaction.

Active Site

The specific region or pocket on an enzyme where substrate molecules bind to undergo a chemical reaction.

Protein Denaturation

The loss of a protein's secondary, tertiary, and quaternary structures caused by environmental stressors like extreme heat or pH, leading to a loss of biological function.

Active Learning

An interactive instructional method where students actively engage with course concepts through in-class problem solving and iClicker questions, proven to lower course failure rates and improve conceptual understanding.