1. Macromolecules: These are very large molecules, formed by polymerization of smaller molecules and may contains hundreds to thousands of smaller molecules. For example: carbohydrate is a macromolecule and is composed of monosaccharides.
Functional groups: group of atoms or bonds, within a molecule, that are characterized by specific set of chemical reactions of that molecule. An example of functional group is hydroxyl (which renders the name alcohol to the particular molecule).
2. The most common types of macromolecules include carbohydrate (e.g., starch, glycogen), nucleic acids (e.g., DNA and RNA), proteins (e.g., collagen, elastin) and lipids (e.g., fats, waxes). The six elements that are part of these macormolecules are Carbon, nitrogen, hydrogen, oxygen. sulphur and phosphorous.
3. Carbohydrates are composed of monosaccharides, while proteins are composed of amino acids and nucleic acids are composed of nucleotides. Monosaccharides are composed of only C, H and O, while amino acids contain C, N, O and H. Each nucleotide has 5-carbon sugar, a phosphate group and a nitrogenous base.
4. Common feature of lipids is the insolubility in water. They are, otherwise, soluble in a wide variety of organic solvents, but all of them are insoluble in water.
5. Phopholipids are amphiphilic lipids that are major components of cell membrane (as lipid bilayer). By ampiphilic, we mean that they contain both hydrophobic and hydrophilic components. More accurately, phospholipids contain a hydrophilic (water loving) head and a hydrophobic (Water hating) tail. It is this property (amphiphilic nature) that enables them to form the lipid bilayer, which is an essential component of cell membrane.
6. Macromolecules are formed by dehydration synthesis, a reaction in which monomers form covalent bonds and polymerize. In this sysnthesis reaction, water molecules are released.
The destruction or degradation of various macromolecules can take place through microbial degradation or denaturation reactions. During the destruction of these macromolecules, water molecules are released.
7. All the carbohydrate molecules are composed of carbon, hydrogen and oxygen.
8. Monosaccharides, such as glyceraldehyde, are the smallest carbohydrates and cannot be divided further into simpler molecules. Disaccharides, are composed of two monosaccharides. Examples of disaccharides include lactose and sucrose.