alpha-helix structure (α-helix)- type of secondary protein structure formed by folding the polypeptide into a helix shape with hydrogen bonds stabilizing the structure

amino acid- a protein's monomer; 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; the R group is different for all 20 common amino acids

beta-pleated sheet (β-pleated)- secondary structure in proteins in which hydrogen bonding forms “pleats” between atoms on the polypeptide chain's backbone

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 and form
arthropods' cellular exoskeleton
cellulose - polysaccharide that comprises the plants' cell wall; provides structural support to the
cell
chitin - type of carbohydrate that forms the outer skeleton of all arthropods that include
crustaceans and insects; it also forms fungi cell walls
dehydration synthesis - (also, condensation) reaction that links monomer molecules, releasing a
water molecule for each bond formed
disaccharide - two sugar monomers that a glycosidic bond links
glycogen - storage carbohydrate in animals
glycosidic bond - bond formed by a dehydration reaction between two monosaccharides with
eliminating a water molecule
hydrolysis - reaction that causes breakdown of larger molecules into smaller molecules by
utilizing water
lipid - macromolecule that is nonpolar and insoluble in water
monomer - smallest unit of larger molecules that are polymers
monosaccharide - single unit or monomer of carbohydrates
phospholipid - membranes' major constituent; comprised of two fatty acids and a phosphate-
containing group attached to a glycerol backbone
polymer - chain of monomer residues that covalent bonds link; polymerization is the process of
polymer formation from monomers by condensation
polysaccharide - long chain of monosaccharides; may be branched or unbranched
saturated fatty acid - long-chain hydrocarbon with single covalent bonds in the carbon chain;
the number of hydrogen atoms attached to the carbon skeleton is maximized
starch - storage carbohydrate in plants
steroid - type of lipid comprised of four fused hydrocarbon rings forming a planar structure
trans fat - fat formed artificially by hydrogenating oils, leading to a different arrangement of
double bond(s) than those in naturally occurring lipids
triacylglycerol (also, 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
hydrocarbon chain
wax - lipid comprised of a long-chain fatty acid that is esterified to a long-chain alcohol; serves
as a protective coating on some feathers, aquatic mammal fur, and leaves