Biologically Important Molecules

• macromolecule: a large, complex molecule, usually composed of repeating units of smaller molecules covalently linked together
• polymer: a large molecule composed of repeating units of smaller molecules (monomers)
• monomer: the smallest repeating unit of a polymer
• carbohydrate: a biological macromolecule that contains carbon, hydrogen and oxygen in 1:2:1 ratio
• isomer: 1 or 2 or more molecules with the same number and type of atoms, but different structural arrangements
• monosaccharide: a carbohydrate composed between three and seven carbon atoms
• disaccharide: a carbohydrate composed of 2 monosaccharides joined by a covalent bond
• polysaccharide: a carbohydrate polymer composed of many monosaccharides joined by covalent bonds between particular atoms
• lipid: a biological macromolecule, composed of carbon, hydrogen, and oxygen atoms, with a high proportion of non-polar carbon-hydrogen bonds
• triglyceride: a lipid molecule composed of a glycerol molecule and three fatty acids linked by ester bonds
• fatty acid: a hydrocarbon chain ending in a carboxyl group 
• phospholipid: a lipid composed of a glycerol molecule bonded to two fatty acids and a phosphate group with an “R” group
• lipid bilayer: a structure with hydrophilic “heads” of phospholipids directed toward the aqueous environment and hydrophobic “tails” directed toward the center, interacting with each other 
• steroid: a lipid composed of 4 attached carbon-based rings
• wax: lipids composed of long carbon-based chains that are solids at room temperature
• protein: a biological macromolecule composed of amino acid monomers linked by covalent bonds
• amino acid: an organic molecule composed of a central carbon atom bonded to a hydrogen atom, an amino group, a carboxyl group, and a variable “R” group
• polypeptide: a polymer composed of many amino acids linked together by covalent bonds
• nucleic acid: biological macromolecules composed of nucleotide monomers
• DNA (deoxyribonucleic acid): a biological macromolecule composed of nucleotides containing the sugar deoxyribose
• RNA (ribonucleic acid): a biological macromolecules composed of nucleotides containing the sugar ribose
• nucleotide: an organic molecule composed of a sugar bonded to a phosphate group and a nitrogen-containing base
• Macromolecule is a large, complex molecule, usually a polymer which is a large molecule composed of repeating units of monomers linked together by covalent bonds. 
• Carbohydrate is composed of C, H and O in the form of (CH2O)n and exists in ring structures.
• Carbohydrate is polar molecule and dissolve in water => hydrophilic
• Function of carbohydrate: short-term energy storage
• glucose + glucose => maltose + H2O
• glucose + galactose => lactose + H2O
• glucose + fructose => sucrose + H2O
• Function of starch: energy storage in plants
• Function of glycogen: energy storage in animals
• Function of cellulose: structural support in plant cell walls
• Many monosaccharides can join together by glycosidic linkages to form a polysaccharide
• Starch and glycogen have alpha form, while cellulose has beta form
• starch and glycogen are digestible, while cellulose are indigestible (carbohydrate)
• starch has branched or unbranched chains
• glycogen has many branched chains
• cellulose has unbranched and linear chains
• glucose consists of ketone functional group
• fructose consists of aldehyde functional group