The Structure and Function of DNA CHAPTER 10 The Hereditary Material: DNA or Protein? DNA and RNA Structure Deoxy- and ribonucleotides Double helical structure of DNA 5' and 3' ends DNA Replication DNA polymerase Semiconservative replication From Gene to Protein Transcription and Translation

Facts About Hereditary Material

DNA: Structure and Replication Was known to be a chemical in cells by the end of the nineteenth century. Has the capacity to store genetic information. Can be copied and passed from generation to generation.

DNA and RNA are nucleic acids. DNA and RNA Structure DNA and RNA are nucleic acids. They consist of chemical units called nucleotides. The nucleotides are joined by a sugar-phosphate backbone. Hershey-Chase Experiment Phage T2 Reproductive Cycle DNA and RNA Structure

DNA is a Double-Stranded Chain of Nucleotides

DNA Chains Are Held Together By Nitrogenous Base H-Bonds

Watson and Crick’s Discovery of the Double Helix James Watson and Francis Crick determined that DNA is a double helix in 1953.

DNA Replication When a cell or whole organism reproduces, a complete set of genetic instructions must pass from one generation to the next DNA Replication occurs in S phase of Interphase One DNA double-helix becomes two identical double helices: sister chromatids S G1 G2 M DNA Replication

Each Chromosome “Unzips” as a New Complementary Strand is Synthesized Along Side the Old One Replication Figure 10.6

DNA can be damaged by ultraviolet light. The enzymes and proteins involved in replication can repair the damage.

How Do Chromosomes Carry Information? A karyotype made from chromosomes of a single cell

Central Dogma of Biology: How Shape and Form Are Dictated By DNA Genes Genotype: The genes carried in a cell for a particular trait A segment of DNA (gene) carries specific coded instructions for the making of a single proteins. Phenotype: The physical expression of genes for a particular trait