AP Bio Unit 1

hydrolysis

chemical reaction

water molecule added

break chemical bonds of a larger compound

polymers broken down → monomers

dehydration synthesis

chemical reaction

builds large polymers from smaller monomers

removing a water molecule

saturated fatty acid / unsaturated fatty acid

the presence / absence of carbon-carbon double bonds in their hydrocarbon chains

fatty acids make up the hydrophobic tails of phospholipids in cell membranes

saturated: only single bonds btwn C and hydrocarbon chain (carbon skeleton), straight line→fatty acids can stack on top of each other

unsaturated: >= 1 double bonds, kinked/bend, packed loosely

peptide bond

covalent chem bond

links two amino acids tgt during protein synthesis

form polypeptides/proteins

formed through dehydration synthesis

covalent bond formed btwn C atom of the carboxyl group (COOH) of one amino acid & N atom of the amino group (NH2) of an adjacent amino acid

cohesion

adhesion

hydrogen bond

phospholipid

amphipathic lipid molecule made of

• glycerol backbone

• polar phosphate head group

• two nonpolar fatty acid tails

form the primary structural basis of cell membranes

polar head: phosphate group (PO4) and glycerol→hydrophilic (water-loving) & charged→interacts with water

non-polar tails: two long hydrocarbon chains (fatty acids) that are hydrophobic (water-fearing) & repel water

spontaneous bilayer formation: in aqueous (watery) environments, self-organize into a phospholipid bilayer, hydrophilic heads facing outward toward the cytoplasm and extracellular fluid, and hydrophobic tails tucked safely inside the core

selective permeability: The hydrophobic interior acts as a barrier that stops large, polar, or charged molecules from crossing freely, while allowing small, nonpolar molecules to slip through

membrane fluidity: saturated & unsaturated fatty acid tails adjust membrane flexibility; kinks in unsaturated tails prevent tight packing in cold environments to keep the membrane fluid

polypeptide

cholesterol

amino acid

monosaccharide

hydrophobic / hydrophilic

deoxyribonucleic acid

disulfide bridges