Transcript DNA Notes
DNA Structure and Function Watson and Crick • An Englishman and an American discovered the structure of DNA in 1954. • 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. DNA Facts • There is 6 feet of DNA in EVERY cell in your body • Your DNA contains over 3 Billion base pairs • Your DNA has over 23,000 genes which means you can produce 23 thousand different protiens. RNA • Two types a. mRNA=messenger b. tRNA = transfer • Single strand • Ribose backbone • Substitutes Uracil (U) for Thymine (T) 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 Translantion Protein Synthesis Models • https://www.youtube.com/watch?v=NJxob gkPEAo&list=FLEezLUmpa3vfMmQGp1aPTQ&feature=mh_lolz • https://www.youtube.com/watch?v=Nmqhd ozuf7Y&list=FLEezLUmpa3vfMmQGp1aPTQ&index=1 Genetic Mutation • Point mutation- substitution, addition or removal of a single nucleotide. - substitution can cause a change in the amino acid sequence - Deletion and addition mutation can cause a frameshift which means that the order of amino acids changes. Sickle Cell Anemia