ABSTRACT
This chapter provides a brief introduction to molecular biology, especially to DNA and protein sequences. The molecules of the cell are of two classes: large and small. The large molecules, known as macromolecules, are of three types: DNA, RNA, and proteins. These are the molecules of most interest to us and they are made by joining certain small molecules together in polymers. DNA is the basis of heredity and it is a polymer, made up of small molecules called nucleotides. These nucleotides are four in number and can be distinguished by the four bases: adenine, ctyosine, guanine, and thymine. DNA carries the genetic material–the information required by an organism to function. DNA is also the means by which organisms transfer genetic information to their descendants. In organisms with a nucleus, DNA remains in the nucleus; whereas proteins are made in the cytoplasm outside of the nucleus.
