Ch 5 (pp 67-75)

Nomenclature and Biochemical Identification of Carbons

• Biochemists use two systems for carbon identification: numbering and Greek letters
• Monosaccharides are simple sugars with a linear chain of three or more carbon atoms
• Monosaccharides have hydroxyl groups and are classified based on the number of carbons
• Simple monosaccharides have the general formula CnH2nOn and are named with the suffix "-ose"
• Monosaccharides are classified as aldoses or ketoses based on the carbonyl group type
• D and L designations are used to describe monosaccharide stereoisomers
• Stereoisomers differ in the position of hydroxyl groups on asymmetric carbons
• Epimers are stereoisomers that differ in the position of hydroxyl groups at one asymmetric carbon
• Monosaccharides mainly exist in ring structures in solution
• D-glucose's old name is dextrose, and it undergoes mutarotation in solution
• Substituted sugars contain phosphate, amino, sulfate, or N-acetyl groups
• Sugars can be oxidized at the aldehyde carbon to form an acid

Functional Groups in Biologic Compounds

• Organic molecules are composed mainly of carbon and hydrogen, with unique characteristics related to functional groups containing oxygen, nitrogen, phosphorus, or sulfur.
• Carbohydrates, also known as sugars, can be classified based on their carbonyl group, number of carbons, hydroxyl group positions, substituents, and the number of monosaccharides joined through glycosidic bonds.
• Glycoproteins and proteoglycans have sugars attached to their protein components.
• Lipids, defined by their hydrophobicity, include fatty acids, sphingolipids, glycolipids, cholesterol, and ketone bodies such as β-hydroxybutyrate, acetoacetate, and acetone.
• Nitrogen-containing compounds like amino acids, purines, pyrimidines, pyridines, nucleosides, and nucleotides contain nitrogen in amino groups or heterocyclic ring structures.
• Ketone bodies are synthesized in the liver and include β-hydroxybutyrate, acetoacetate, and acetone, with the latter accounting for the sweet mousy odor in ketoacidosis patients' breath.
• Amino acids contain a carboxyl group, an amino group, and additional carbons, while screening tests for ketone bodies employ a paper strip containing nitroprusside.
• The organic molecules of the body consist mainly of carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus joined by covalent bonds, with carbon forming the key element.
• Functional groups in biochemical molecules involve bonds between carbon and oxygen, carbon and nitrogen, carbon and sulfur, or carbon and phosphate groups, determining the types of reactions and physiologic roles.
• Carbon structures with different numbers of carbons and hydrogen, straight or branched, with or without a ring, are named based on their carbon skeleton and functional groups.
• Carbon-containing rings, such as the six-membered carbon-containing benzene ring, are found in biologic compounds and are called aromatic.
• The properties of functional groups determine the types of reactions and the physiologic role of the molecule, with carbon–oxygen and carbon–nitrogen bonds being polar and more reactive than carbon–carbon and carbon–hydrogen bonds.