# Biochemistry

## Vocabulary

### active site

place on an enzyme where the substrate binds and the reaction occurs

biological unit of energy, which consists of an adenosine (an adenine group and a ribose sugar) and three phosphate groups

### alpha helix

helical structure of proteins that adopts a right-handed-spiral conformation, where chain backbone ${\rm{N}{-}\rm{H}}$ groups form hydrogen bonds with ${\rm{C}{=}\rm{O}}$ groups of nearby amino acids along the protein chain

### amino acid

protein-building molecule that contains an amino group (${\rm{{-}NH}}_2$), a carboxyl group ($\rm{{-}COOH}$), and between them a carbon atom attached to a side chain

### beta pleated sheet

structure of amino acids that takes the shape of a pleated sheet folded at regular intervals

### glucose

monosaccharide (simple sugar) used for energy in biological systems

### lipid

hydrophobic macromolecule that may provide storage, structure, or nutrients in organisms

### monosaccharide

single (simple) sugar molecule

### nucleotide

organic compound that forms the basis of a genetic sequence, consisting of a sugar, a phosphate, and a nitrogenous base

### peptide bond

covalent amide ($\rm{{-}CONH{-}}$) bond that forms between two adjacent amino acids along the same peptide chain. The bond forms between the amine group of one amino acid and the carboxyl ($\rm{{-}COOH}$) group of another.

### phospholipid

lipid that usually consists of two fatty acid tails covalently linked to a common phosphate group

### polysaccharide

carbohydrate polymer consisting of many monosaccharides that form a long chain

### primary structure

sequence of amino acids linked by peptide (amide) bonds to form a polypeptide chain

### quaternary structure

two or more chains of proteins that interact with one another

### secondary structure

structure of a protein that is the initial folding of the amino acid polymer that arises from hydrogen bonding between the amine and carboxyl groups of amino acids in neighboring parts of the chain

### steroid

lipid that contains a core with four fused ring structures (three 6- and one 5-membered ring) that serves as a precursor to hormones, cholesterol, or other molecules

### substrate

molecule that is acted upon by an enzyme by binding to the enzyme's active site

### tertiary structure

structure of a protein produced by interactions between the R groups of the amino acids in the chain and with the environment around them