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Nucleic Acids and the Central Dogma SJCHS
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Review Function: Information storage Deoxyribonucleic Acid (DNA) Ribonucleic Acid (RNA) Monomer is a nucleotide; contains a sugar, a phosphate, and a nitrogen base
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History Experiments that discovered DNA, established as the genetic material
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History 1869: Friedrich Miescher : DNA discovered
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Structure- DNA Chromosomes- Packages of DNA Nucleosomes: DNA wrapped around Histones (proteins) Coils further to make chromosomes
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History Phoebus Levene- 1919 Phosphate group Sugar Base 4 Nitrogen Bases Adenine Guanine Thymine Cytosine Polynucleotide: Made up of long chains of nucleotides (monomer)
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History 1950 ’ s: Erwin Chargaff Nitrogen bases A is in the same amount as T C is in the same amount as G
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DNA and RNA Phosphate groups- same Sugar DNA: Deoxyribose RNA: Ribose Nitrogen Base DNA: A,T,C,G RNA: A, U, C, G
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History Franklin and Gosling: X Ray Pictures of DNA DNA: Double helix
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History 1952: Alfred Hershey and Martha Chase: DNA confirmed as the genetic material using T2 phage virus and E. coli
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Virus Viruses: Nucleic acids (DNA or RNA) enclosed in a protein Not alive Not cellular, cannot reproduce on its own
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Virus Hunter http://video.pbs.org/video/2163879922/
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Life Cycle Bacteriophage: Bacterial viruses 2 types of phage life cycles Lytic Cycle: Host cell used as virus making factory then is destroyed
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Life Cycle Lysogenic Cycle: Host cell is not destroyed, virus remains “ dormant ” Prophage: Phage DNA that has been inserted into host DNA
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http://highered.mcgraw- hill.com/olc/dl/120076/bio21.swf
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History 1953: Crick, Watson: Structure of DNA
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Structure-DNA DNA- double helix (two DNA strands held by hydrogen bonds between nitrogen bases) A bonds to T G bonds to C
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DNA and RNA Sugars and phosphates bond together, forming a sugar phosphate backbone
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DNA and RNA Information in a cell refers to the instructions for making proteins DNA: Original instructions RNA: Copies of the instructions
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Flow of Genetic Information DNA Replication- makes more DNA Transcription- Makes RNA Translation- Makes polypeptides (proteins)
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Structure-DNA DNA is divided into sections called genes that has the instructions to make a polypeptide Genome: All of the genes in an organism
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Structure-RNA mRNA: Messenger RNA Genetic information to make protein Transcription and Translation
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Structure-RNA tRNA: Transfer RNA- helps to make polypeptides RNA strand bonds with itself (A-U and C-G) Translation
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Structure-RNA rRNA: Ribosomal RNA Ribosome: Organelle where polypeptides are made (made of rRNA and proteins) Translation
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Flow of Genetic Information
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Genetic Code Codon- 3 nucleotides that “ code ” for a specific amino acid Genetic code is degenerate and universal
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Examples
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HIV Exceptions to Central Dogma: Retrovirus: Virus that reproduces by transcribing RNA into DNA Reverse transcriptase: Enzyme that allows DNA to be made from RNA
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HIV HIV- Human immunodeficiency virus AIDS- Disease caused by HIV HIV kills/infects white blood cells
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HIV 1.RNA used as template to make DNA 2.DNA enters cell nucleus
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HIV 3.Provirus transcribed into RNA 4.RNA translated into viral proteins 5.New viruses assembled
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HIV news story
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