AP Bio Unit 1 Vocabulary List

alpha-helix structure (α-helix)

Type of secondary structure of proteins formed by folding of the polypeptide into a helix shape with hydrogen bonds stabilizing the structure.

amino acid

Monomer of a protein; has a central carbon or alpha carbon to which an amino group, a carboxyl group, a hydrogen, and an R group or side chain is attached.

beta-pleated sheet (β-pleated)

Secondary structure found in proteins in which 'pleats' are formed by hydrogen bonding between atoms on the backbone of the polypeptide chain.

biological macromolecule

Large molecule necessary for life that is built from smaller organic molecules.

carbohydrate

Biological macromolecule in which the ratio of carbon to hydrogen and to oxygen is 1:2:1; carbohydrates serve as energy sources and structural support in cells.

cellulose

Polysaccharide that makes up the cell wall of plants; provides structural support to the cell.

chaperone

Protein that helps nascent proteins in the folding process.

chitin

Type of carbohydrate that forms the outer skeleton of all arthropods, including crustaceans and insects.

dehydration synthesis

Reaction that links monomer molecules together, releasing a molecule of water for each bond formed.

denaturation

Loss of shape in a protein as a result of changes in temperature, pH, or exposure to chemicals.

deoxyribonucleic acid (DNA)

Double-helical molecule that carries the hereditary information of the cell.

disaccharide

Two sugar monomers that are linked together by a glycosidic bond.

enzyme

Catalyst in a biochemical reaction that is usually a complex or conjugated protein.

glycogen

Storage carbohydrate in animals.

glycosidic bond

Bond formed by a dehydration reaction between two monosaccharides with the elimination of a water molecule.

hormone

Chemical signaling molecule, usually protein or steroid, secreted by endocrine cells to control or regulate specific physiological processes.

hydrolysis

Reaction that causes breakdown of larger molecules into smaller molecules with the utilization of water.

lipid

Macromolecule that is nonpolar and insoluble in water.

messenger RNA (mRNA)

RNA that carries information from DNA to ribosomes during protein synthesis.

monomer

Smallest unit of larger molecules called polymers.

monosaccharide

Single unit or monomer of carbohydrates.

nucleic acid

Biological macromolecule that carries the genetic blueprint of a cell and carries instructions for cell functioning.

nucleotide

Monomer of nucleic acids; contains a pentose sugar, one or more phosphate groups, and a nitrogenous base.

omega fat

Type of polyunsaturated fat that is required by the body.

peptide bond

Bond formed between two amino acids by a dehydration reaction.

phosphodiester linkage

Covalent bond that holds together the polynucleotide chains, with a phosphate group linking two pentose sugars.

phospholipid

Major constituent of membranes; composed of two fatty acids and a phosphate-containing group attached to a glycerol backbone.

polymer

Chain of monomer residues linked by covalent bonds.

polynucleotide

Long chain of nucleotides.

polypeptide

Long chain of amino acids linked by peptide bonds.

polysaccharide

Long chain of monosaccharides; may be branched or unbranched.

primary structure

Linear sequence of amino acids in a protein.

protein

Biological macromolecule composed of one or more chains of amino acids.

purine

Type of nitrogenous base in DNA and RNA; adenine and guanine are purines.

pyrimidine

Type of nitrogenous base in DNA and RNA; cytosine, thymine, and uracil are pyrimidines.

quaternary structure

Association of discrete polypeptide subunits in a protein.

ribonucleic acid (RNA)

Single-stranded molecule involved in protein synthesis.

ribosomal RNA (rRNA)

RNA that ensures proper alignment of mRNA and ribosomes during protein synthesis.

saturated fatty acid

Long-chain of hydrocarbon with single covalent bonds in the carbon chain.

secondary structure

Regular structure formed by proteins by intramolecular hydrogen bonding.

starch

Storage carbohydrate in plants.

steroid

Type of lipid composed of four fused hydrocarbon rings.

tertiary structure

Three-dimensional conformation of a protein.

trans fat

Fat formed artificially by hydrogenating oils.

transcription

Process through which messenger RNA forms on a template of DNA.

transfer RNA (tRNA)

RNA that carries activated amino acids to the site of protein synthesis.

translation

Process through which RNA directs the formation of protein.

triacylglycerol (triglyceride)

Fat molecule; consists of three fatty acids linked to a glycerol molecule.

unsaturated fatty acid

Long-chain hydrocarbon that has one or more double bonds in the chain.

wax

Lipid made of a long-chain fatty acid that acts as a protective coating.

acid

Molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a solution.

adhesion

Attraction between water molecules and other molecules.

aliphatic hydrocarbon

Hydrocarbon consisting of a linear chain of carbon atoms.

anion

Negative ion formed by an atom gaining electrons.

aromatic hydrocarbon

Hydrocarbon consisting of closed rings of carbon atoms.

atom

The smallest unit of matter that retains all chemical properties of an element.

atomic mass

Calculated mean of the mass number for an element’s isotopes.

atomic number

Total number of protons in an atom.

balanced chemical equation

Statement of a chemical reaction with equalized number of each type of atom.

base

Molecule that donates hydroxide ions or binds excess hydrogen ions.

buffer

Substance that resists changes in pH by absorbing or releasing ions.

calorie

Amount of heat required to change the temperature of one gram of water by one degree Celsius.

capillary action

Occurs because water molecules are attracted to charges on surfaces, drawing water to the sides of narrow structures.

cation

Positive ion formed by an atom losing one or more electrons.

chemical bond

Interaction between atoms that results in formation of molecules.

chemical reaction

Process leading to the rearrangement of atoms in molecules.

chemical reactivity

Ability to combine and bond with each other.

cohesion

Intermolecular forces between water molecules caused by the polar nature of water.

compound

Substance composed of molecules with atoms from at least two different elements.

covalent bond

Strong bond formed when electrons are shared between atoms.

dissociation

Release of an ion from a molecule, resulting in a charged molecule and original ion.

electrolyte

Ion necessary for nerve impulse conduction and muscle contractions.

electron

Negatively charged subatomic particle residing outside of the nucleus.

electron configuration

Arrangement of electrons in an atom’s electron shell.

electron orbital

Space surrounding the nucleus where an electron is likely to be found.

electron transfer

Movement of electrons from one element to another.

electronegativity

Ability of some elements to attract electrons.

element

One of 118 substances that cannot be broken down further.

enantiomers

Molecules that are mirror images of each other, differing in three-dimensional arrangement.

equilibrium

Steady state of relative reactant and product concentration in reversible chemical reactions.

evaporation

Separation of individual molecules from a surface.

functional group

Group of atoms that provides a specific function to a carbon skeleton.

geometric isomer

Isomer differing in the placement of atoms alongside a double bond.

heat of vaporization of water

High amount of energy required for liquid water to vaporize.

hydrocarbon

Molecule consisting only of carbon and hydrogen.

hydrogen bond

Weak bond between slightly charged hydrogen atoms and other atoms.

hydrophilic

Describes ions or polar molecules that interact well with water.

hydrophobic

Describes uncharged non-polar molecules that do not interact well with water.

inert gas

Element with filled outer electron shell that is unreactive.

ion

Atom or chemical group with an unequal number of protons and electrons.

ionic bond

Chemical bond that forms between ions with opposite charges.

irreversible chemical reaction

Chemical reaction where reactants proceed uni-directionally to form products.

isomers

Molecules that differ despite having the same chemical formula.

isotope

Forms of an element with different numbers of neutrons.

law of mass action

Reaction rate is proportional to the concentration of reacting substances.

litmus paper

Filter paper used as a pH indicator.

mass number

Total number of protons and neutrons in an atom.

matter

Anything that has mass and occupies space.

molecule

Two or more atoms chemically bonded together.

neutron

Uncharged particle residing in the nucleus of an atom.