AP Biology Chemistry of Life Vocabulary

A complete set of vocabulary flashcards covering Topics 1.0 through 1.7 of AP Biology Unit 1.

covalent bond

A chemical bond formed when two atoms share one or more pairs of electrons.

electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

electronegativity

A measure of the tendency of an atom to attract a bonding pair of electrons.

element

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

ion

An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.

ionic bond

A chemical bond formed through the electrostatic attraction between oppositely charged ions.

molecule

A group of two or more atoms held together by chemical bonds.

neutron

A subatomic particle with no electric charge located in the nucleus of an atom.

proton

A positively charged subatomic particle located in the nucleus of an atom.

adhesion

The attraction between molecules of different substances.

cohesion

The attraction between molecules of the same substance, such as hydrogen bonding between water molecules.

hydrogen bond

A weak chemical bond formed when a slightly positive hydrogen atom is attracted to a strongly electronegative atom.

polar

Having an uneven distribution of electrical charge across a molecule, creating distinct positive and negative poles.

hydrophilic

Having an affinity for water; readily interacting with or dissolving in water.

hydrophobic

Repelling water; tending not to dissolve in or mix with water.

surface tension

A measure of how difficult it is to stretch or break the surface of a liquid due to cohesive forces.

monomer

A small repeating molecular subunit that can bind to other similar molecules to form a polymer.

polymer

A large molecule composed of many repeating monomer subunits linked together by covalent bonds.

polymerization

The chemical process of joining monomer subunits together to form a polymer chain.

dehydration synthesis

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

hydrolysis

A chemical process that cleaves a covalent bond by adding a water molecule.

monosaccharide

The simplest carbohydrate monomer consisting of a single sugar molecule.

polysaccharide

A complex carbohydrate polymer composed of many monosaccharide units linked by glycosidic bonds.

glycogen

A highly branched glucose storage polysaccharide found in animals, primarily in liver and muscle cells.

starch

A plant storage polysaccharide composed of glucose monomers.

cellulose

A structural polysaccharide composed of glucose monomers that forms plant cell walls.

glycerol

A three-carbon alcohol with three hydroxyl groups that serves as the backbone for triglycerides and phospholipids.

fatty acid

A molecule consisting of a long hydrocarbon chain attached to a carboxyl group.

saturated fatty acid

A fatty acid with no double bonds between carbon atoms, containing the maximum number of hydrogen atoms.

unsaturated fatty acid

A fatty acid containing one or more double bonds between carbon atoms, resulting in fewer hydrogen atoms.

phospholipid

A lipid composed of glycerol attached to two fatty acids and a phosphate group, forming the primary component of cell membranes.

fat

A lipid molecule composed of glycerol bonded to three fatty acid chains, also known as a triglyceride.

steroid

A class of lipids characterized by a carbon skeleton consisting of four fused rings.

cholesterol

A type of steroid that is an essential component of animal cell membranes and acts as a precursor for steroid hormones.

DNA

Deoxyribonucleic acid; a double-stranded nucleic acid that stores genetic information using deoxyribose sugar and nitrogenous bases adenine, thymine, cytosine, and guanine.

RNA

Ribonucleic acid; a single-stranded nucleic acid involved in protein synthesis, containing ribose sugar and nitrogenous bases adenine, uracil, cytosine, and guanine.

nucleotide

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

nitrogenous base

A nitrogen-containing organic molecule that forms part of a nucleotide, such as adenine, guanine, cytosine, thymine, or uracil.

adenine

A purine nitrogenous base found in both DNA and RNA that pairs with thymine in DNA and uracil in RNA.

guanine

A purine nitrogenous base found in both DNA and RNA that pairs with cytosine.

cytosine

A pyrimidine nitrogenous base found in both DNA and RNA that pairs with guanine.

thymine

A pyrimidine nitrogenous base found only in DNA that pairs with adenine.

uracil

A pyrimidine nitrogenous base found only in RNA that pairs with adenine.

5' phosphate end

The terminal end of a nucleic acid strand attached to the fifth carbon of the sugar ring, bearing a free phosphate group.

3' hydroxyl end

The terminal end of a nucleic acid strand attached to the third carbon of the sugar ring, bearing a free hydroxyl group.

peptide bond

The covalent bond formed between the carboxyl group of one amino acid and the amine group of another during protein synthesis.

carboxyl group

A functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (-COOH).

amine group

A functional group consisting of a nitrogen atom bonded to hydrogen atoms (-NH2).

R group

The variable side chain attached to the central carbon of an amino acid that determines its unique chemical properties.

primary structure

The specific linear sequence of amino acids in a polypeptide chain.

secondary structure

The local folding or coiling pattern of a polypeptide chain, such as alpha helices or beta pleated sheets, maintained by hydrogen bonds.

tertiary structure

The overall three-dimensional shape of a single polypeptide chain, stabilized by interactions among R groups.

quaternary structure

The structural arrangement resulting from the assembly of two or more polypeptide subunits into a functional protein complex.