AP Biology- Unit 5, Biochemistry

Macromolecule

A giant molecule formed by the joining of smaller molecules, usually by a dehydration reaction.

Polymer

A long molecule consisting of many similar or identical monomers linked together by covalent bonds.

Monomer

The subunit that serves as the building block of a polymer.

Dehydration Reaction/Synthesis

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

Hydrolysis

A chemical reaction that breaks bonds between two molecules by the addition of water; functions in disassembly of polymers to monomers

Carbohydrate

A sugar (monosaccharide) or one of its dimers (disaccharides) or polymers (polysaccharides)

Monosaccharide

The simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides. Also called simple sugars, monosaccharides have molecular formulas that are generally some multiple of CH2O.

Glucose

A common monosaccharide that in excess, will convert to starch or glycogen in plant and animal cells, respectively.

Disaccharide

A double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed by a dehydration reaction.

Maltose

A common polysaccharide formed by two glucose molecules.

Lactose

A common polysaccharide formed by two glucose molecules.

Polysaccharide

A polymer of many monosaccharides, formed by dehydration reaction.

Cellulose

A structural polysaccharide of plant cell walls, consisting of glucose monomers joined by beta glycosidic linkages.

Starch

A polymer of glucose monomers, as granules within cellular structures known as plastids.

Glycogen

An extensively branched glucose storage polysaccharide found in the liver and muscle of animals; the animal equivalent of starch.

Chitin

A structural polysaccharide, consisting of amino sugar monomers, found in many fungal cell walls and in the exoskeletons of all anthropods.

Lipid

Any of a group of large biological molecules, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.

Glycerol

An organic three carbon alcohol, each carbon has a hydroxyl group which is involved in the binding of a fatty acid.An organic three carbon alcohol, each carbon has a hydroxyl group which is involved in the binding of a fatty acid.

Fatty Acid

A carboxylic acid with a long carbon chain. Fatty acids vary in length in the number and location of double bonds; three fatty acids linked to a glycerol molecule form a fat molecule, also called triacylglycerol or triglyceride.

Saturated Fatty Acid

A fatty acid in which all carbons in the hydrocarbon tail are connected.

Unsaturated Fatty Acid

A fatty acid that has one or more double bonds between carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

Carbonyl Group

A chemical group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom also bonded to a hydroxyl group.

Phospholipid

A lipid made up of glycerol joined to two fatty acids and a phosphate group. The hydrocarbon chains of the fatty acids act as nonpolar, hydrophobic tails, while the rest of the molecule acts as a polar, hydrophilic head. Phospholipids form bilayers that function as biological membranes.

Steroid

A type of lipid characterized by a carbon skeleton consisting of four fused rings with various chemical groups attached.

Cholesterol

A steroid that forms an essential component of animal cell membranes and acts as a precursor molecule for the synthesis of other biologically important steroids, such as many hormones.

Triglyceride

A lipid consisting of three fatty acids linked to one glycerol molecule; also called a fat or triacylglycerol.

Hydrophobic

Having no affinity for water; tending to coalesce and form droplets in water.

Hydrophilic

Having an affinity for water

Protein

A biologically functional molecule consisting of one or more polypeptides folded and coiled into a specific dimensional structure.

Polypeptide

A polymer of many amino acids linked together by peptide bonds.

Amino Acid

An organic molecule possessing both a carboxyl and an amino group. Amino acids serve as the monomers of polypeptides

Amino Group

A chemical group consisting of a nitrogen atom bonded to two hydrogen atoms; can act as a base in a solution, accepting a hydrogen ion and acquiring a charge of 1+.

Peptide Bond

The covalent bond between the carboxyl group on one amino acid and the amino group on another, formed by a dehydration reaction

Dipeptide

A dimer of two amino acids linked together by peptide bonds

Denaturation

In proteins, a process in which a protein loses its native shape due to the disruption of weak chemical bonds and interactions, thereby becoming biologically inactive; in DNA, the separation of two strands in the double helix. Denaturation occurs under extreme (noncellular) conditions of pH, salt concentration, or temperature.