Somatic cells are any cells of the body which have 2N chromosomes, also know as being diploid. This means that a somatic cell has two copies of each chromosome. Somatic cells comprise the vast majority of the body's cells, and perform virtually all of its life functions, including reproducing themselves through the process of mitosis, which produces two genetically identical daughter cells.
Gametes are cells which are 1N, or haploid. In this case the cell has only one copy of each chromosome. Gametes are produced through the process of meiosis, which separates the chromosomes so that each of the four daughter cells produced has one set of chromosomes. Gametes can develop into egg cells or sperm cells and fuse to form a new, genetically unique individual.