DNA Roles of DNA 1. 2. Pop Quiz 1. What was the main goal of Griffiths experiment? What was the procedure? What were the results? 2. What was the main goal of the experiment performed by Hershey and Chase? What was the procedure? What were the results? 3. How did Watson and Crick use the discoveries of scientists before them to develop the alpha helix model of DNA? Discovery Griffiths Experiment (1928) Avery (1944) Chargaff (1949) Hershey and Chase Wilkins and Franklin (1952) Nucleotides A Closer look Watson, Crick, and the Double Helix Nucleotides A Closer look Base Pairing Rules Human Genome Project DNA Replication Protein Synthesis Part I: Transcription Part II: Translation Gene Expression/Regulation in Prokaryotes Gene Expression in Eukaryotes Homeotic Genes Homeotic Genes/Homeobox DNA Structure and Function Watson and Crick An Englishman and an American discovered the structure of DNA in DNA is to small to see so they had to build a model using x-Rays and chemical information about Nitrogen bases They Had Some Help Roselyn Franklin took this x-ray picture of DNA which lead Watson and Crick to the double helix structure of DNA but they failed to give her credit until much later. Double Helix DNA consists of two strips, made of sugars and phosphates, twisted around each other and connected by nitrogen bases. Looks like a spiral staircase or a twisted ladder. Sugar Backbone The backbone of DNA is made up of Deoxyribose (Sugar) molecules connected to each other using Phosphates Nitrogen Bases DNA contains 4 nitrogen bases that make up the code for all living things. A = Adenine T = Thymine G = Guanine C = Cytosine A always bonds to T G always bonds to C Nucleotide The combination of a sugar, phosphate and nitrogen base is called a Nucleotide. These are the building blocks of DNA. Key Words for Protein Synthesis Gene- section of DNA that codes for a specific protein. Messenger RNA (mRNA)- nucleic acid that copies the DNA and takes it to the Ribosome. Ribosome- Organelle that builds proteins using mRNA and tRNA. Transfer RNA (tRNA)- nucleic acid that matches up codon to anticondon and drops off amino acids in the correct order. Key Words Continued Codon- Group of three nitrogen bases found on the mRNA that codes for a specific amino acid. Anticodon- Group of three nitrogen bases found on the tRNA that matches up with the codon and drops off the correct amino acid. Amino Acid- Building blocks of proteins that are placed in the correct order by matching codon to anticodon along the length of a gene. Steps to Protein Synthesis Transcription DNA Opens one Gene One side of the DNA is copied by the mRNA mRNA travels outside the Nucleus to the Ribosome Translation Ribosome attaches to the mRNA. tRNA matches up codon to anticodon and drops off the correct amino acid A chain of amino acids is created which is a protein Translation Protein Synthesis Models https://www.youtube.com/watch?v=NJxobgkP EAo&list=FLEezLUm- pa3vfMmQGp1aPTQ&feature=mh_lolz https://www.youtube.com/watch?v=NJxobgkP EAo&list=FLEezLUm- pa3vfMmQGp1aPTQ&feature=mh_lolz https://www.youtube.com/watch?v=u9dhO0iCLww&list=FLEezLUm-pa3vfMmQGp1aPTQ