1/18/2016 Genomes Vary in Size Genome:Structure and Function ·Smallest genome viral encoding 4-5 genes Escherchia coli single chromosome containing 4,288 genes 1 mm long 1,000X longer than cell Human cell DNA emerging from a 46 chromo disrupted Escherichia coli containing 31,000 genes cell as a single chromosome 6 feet long 180,000X longer than cell Genes Chromosomes are subdivided into genes.the fundamental unit of heredity responsible for a Cell given trait. DNA Gene:a segment of DNA that encodes a functional product,usually a protein Three basic categories of genes: 1.Genes that code for proteins structural genes Nucleus Chromosome 2.Genes that code for RNA 3.Genes that control gene expression regulatory genes 1/18/2016 2 Genome: Structure and Function Genomes Vary in Size • Smallest genome viral encoding 4-5 genes • Escherchia coli single chromosome containing 4,288 genes 1 mm long 1,000X longer than cell • Human cell 6 46 chromosomes containing 31,000 genes 6 feet long 180,000X longer than cell DNA emerging from a disrupted Escherichia coli cell as a single chromosome • Chromosomes are subdivided into genes, the fundamental unit of heredity responsible for a given trait. Genes g ven tra t. • Gene: a segment of DNA that encodes a functional product, usually a protein Three basic categories of genes: 1. Genes that code for proteins structural genes 2. Genes that code for RNA 3. Genes that control gene expression regulatory genes