STRUCTURE OF MACROMOLECULAR COMPOUNDS Carbohydrate Carbohydrates can be divided into three groups, namely monosaccharides, disaccharides, oligosaccharides and polysaccharides. Based on the types of carbohydrate compounds present, four groups of carbohydrate compounds can be displayed. Of the four types of carbohydrate compounds, only the oligosaccharide and polysaccharide groups are categorized as macromolecular compounds. Monosaccharides Simple monosaccharides that are commonly known from carbohydrate compounds are glucose and fructose. These two compounds are isomers that have the same molecular formula but different molecular structures. Glucose is a derivative of aldose which is a group of aldehyde compounds while fructose is a derivative of ketode compounds which are a group of ketose compounds. In general, other monosaccharide compounds are also isomerizations of glucose (aldose group) where the differences in the positions of –OH and –H on C atoms 2,3,4 and 5 are the basis for the differences between the compounds. the. Monosaccharides are hypothesized to exist in the form of linear chains and/or as cyclic molecules; in aqueous solutions, these compounds are usually found in cyclic form. Disaccharides Disaccharides (di- = "two") are formed when two monosaccharides undergo a dehydration reaction (a reaction in which the release of water molecules occurs).During this process, the hydroxyl group (–OH) of one monosaccharide combines with the hydrogen atom of another monosaccharide, releasing a water molecule (H2O) and forming a covalent bond between the atoms in the two sugar molecules.The bond formed is also known as a glycoside bond. Common disaccharides include lactose, maltose, and sucrose. Lactose is a disaccharide consisting of glucose and galactose monomers. Lactose is found naturally in milk. Maltose, or malt sugar, is a disaccharide formed from a dehydration reaction between two glucose molecules. The most common disaccharide is sucrose, or table sugar, which consists of glucose and fructose monomers. Oligosaccharides and Polysaccharides Oligosaccharides and polysaccharides are macromolecular groups of carbohydrate compounds. The main difference between oligosaccharides and polysaccharides is the large number of monosaccharides that make up them. If a monosaccharide consists of 3 to 10 molecules, then the compound formed is an olgisaccharide molecule. If there are more than 10 molecules, then the group of compounds formed are polysaccharide molecules.The formation of oligosaccharide and polysaccharide molecules can be composed of one type of monosaccharide or a combination of several types of monosaccharides.Apart from that, the chains formed can also be straight or branched chains. Proteins To recognize the chemical structure of a protein compound, recognition of amino acid molecules as the main constituent of protein compounds is the basis that must be understood. Each amino acid has a basic structure consisting of an amino group, a carboxylate group, a hydrogen group and an alkyl group. The type of filler in the alkyl group that provides variations in the types of amino acids present. There are 20 types of alkyl groups (–R) which can produce 20 types of amino acids. The simplest R group in a protein compound is (–H) which can form a glycine molecule. Peptide bonds are bonds formed from two or more amino acids. Polypeptides are paptide chains of many amino acids. A protein contains one or more polypeptides. Therefore, proteins are long chains of amino acids held together by peptide bonds.To form polypeptides and proteins, amino acids are joined together by peptide bonds, where the amino or NH2 of one amino acid bonds with the carboxyl (acid) or COOH group of another amino acid. From the perspective of macromolecular compounds, protein compounds have four types of structures known as primary, secondary, tertiary and quaternary structures. Primary structure is the most basic structure of a protein molecule where the structure consists of amino acids that are linked together to form a long polypeptide chain. Secondary structure is the structure of a long polypeptide chain that forms folds due to the influence of hydrogen bonds in the amino acid molecules that make up a polypeptide chain. tertiary structure occurs due to the influence of hydrogen bonds such as in the formation of secondary structure coupled with ionic interactions of the alkyl group (–R) of the amino acids that make up the peptide chain. This group has positive and negative charges which can attract or repel each other which creates a globular structure of a protein molecule. This tertiary structure is also known as the three-dimensional structure of an amino acid. The quaternary structure of a protein compound is the most complex structure where all interactions of all the amino acids contained in a protein compound can occur. Nucleic Acid Nucleic acids are polynucleotides. Each nucleotide consists of a nitrogen-containing aromatic base attached to a pentose (five-carbon) sugar, which is also attached to a phosphate group. Any nucleic acid contains four of the five possible nitrogen-containing bases: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U). A and G are categorized as purines, and C, T, and U are collectively categorized as pyrimidines. All nucleic acids contain A, C, and G bases; T. This condition is only found in DNA, while U is found in RNA. The pentose sugar in DNA is different from the sugar in RNA, where in RNA the sugar is ribose with the absence of a hydroxyl group (-OH) on the 2' carbon of the sugar ring. In general, the basic structure of a nucleotide can be described as follows. The differences in the types of nitrogen bases and types of sugars are the basis for the differences in nucleotides from DNA and RNA. Like other polymer molecules, nucleic acid compounds will also be formed from the combination of their monomers. Nucleotide monomers will combine to form a nucleic acid molecule by forming a phosphodiester bond. Phosphodiester bonds occur when two hydroxyl groups on phosphoric acid react with hydroxyl groups on another molecule to form two ester bonds. In DNA and RNA molecules, the phosphodiester bond is a bond between the 3' carbon atom of one sugar molecule and the 5' carbon atom of another sugar molecule which is bridged by the presence of a phosphate group. The combination of these two sugar molecules will involve 12 two oxygens on the phosphate group which results in two phosphodiester bonds.This phosphodiester bond is the basic framework in the formation of long chains of nucleic acid compounds. Lipids Lipids are a large group of organic compounds that are insoluble in water. Lipids are hydrophobic because of their basic framework is a nonpolar molecule. Lipid compounds generally consist of many carbon atoms or have long chains. Lipid compounds are not included in the polymer group because the molecules that make up lipids are not repeats of monomers. In general, lipids are composed of fatty acid molecules which can bind to alcohol molecules in the form of glycerol or long chain alcohols such as cetyl alcohol. This constituent composition will produce lipid molecules in the fat/oil or wax category. The formation of phospholipids is diversification of the combination of glycerol molecules with fatty acids where one of the hydroxyl groups of glycerol will bind to phosphate group. Different from the other three types of lipids such as fats, oils and phospholipids; Steroid molecules are not formed from the combination of two compounds. Steroid compounds consist of cyclic carbon compounds with a total of 17 carbons. The core structure of steroids typically consists of seventeen carbon atoms, bonded in four "fused" rings: three six-membered cyclohexane rings (rings A, B and C in the first illustration) and one five-membered cyclopentane ring (ring D). The bonds formed in fat/oil, phospholipid and wax molecules are ester bonds. General Chemical Properties of Macromolecular Compounds Macromolecular compounds are compounds that have a very large molecular weight which makes the solubility of the compound in water very low. The large number of carbon atoms in a macromolecular compound causes the polarity of the compound to be lost, making it difficult to dissolve in water.The insolubility of macromolecular compounds in water media creates a unique characteristic of these macromolecular compounds, namely the formation of colloids. In addition, because macromolecular compounds are generally formed from the combination of two compound molecules, whether in monomer form or not, each macromolecular compound is bound by a specific bond. The bonds in a macromolecular compound can be broken through a reaction called a hydrolysis reaction. Apart from the hydrolysis reaction, there are several specific reactions that can occur in a macromolecule, these reactions include: gelatinization reactions in carbohydrates, denaturation reactions in proteins, formation of ionic charges in proteins, oxidation reactions in fats/oils, isomerization reactions in fats/ oil.