Genes are the basic unit of heredity that transfer information from one generation to another. A gene is a segment of DNA containing a sequence of nucleotides that encodes for RNA and protein. Eukaryotic genes contain introns and exons, with regulatory sequences like promoters and enhancers/silencers that control gene expression. Prokaryotic genes can be monocistronic or polycistronic operons containing multiple protein coding regions controlled by a single promoter.