ABSTRACT
Cell is the basic unit of life. In the cells of eukaryotes, a nuclear membrane separates the genetic material from the cytoplasm, which is then further subdivided by other distinct membranous structures. The essence of a cell is its ability to grow and divide to produce progeny cells, which are likewise capable of generating new cellular molecules and replicating themselves. This chapter describes three simple molecules: sugars, amino acids and nucleotides. Besides, glucose, ribose and other simple sugars, derivatives of sugars such as uronic acids, amino sugars, or acetylated sugars may also form polymers. Amino acids are chemically varied but they all contain a carboxyl acid group and amino group both linked to a single carbon atom. Nucleotides are subunits of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). The basic control and functioning of the organism is exercised by DNA and RNA.
