Chapter 11 Nucleic Acids: Information storage and transmission.---Nucleotides are the building block molecules of a nucleic acid and are composed of a sugar, a phosphate group, and a nitrogenous base.PowerPoint PresentationSlide 4Slide 5Slide 6Slide 7Evidence that DNA is the genetic material:Slide 9-There was a relationship between the bases Chargaff’s rules A = T G = CSlide 11Remember the structure of the monomer (nucleotide) and the polymer (single strand DNA).Understanding the structure of DNA -Physical structure evidenceSlide 14-2 strands are antiparallel-specific-base pairing complementary base pairs the key to solving puzzle => A-T and G-C pairs, explained Chargaff's rulesDNA lengthGenesSlide 19Slide 20Forensic DNA AnalysisRecombinant DNAInsulinHuman Growth Hormone (HGH)Slide 25Erythropoietin (EPO)Slide 27DNA technology in agricultureSlide 29Featherless chickensIn case you thought I was making this up…….DNA replicationThe process of DNA replication is conceptually easy, but reality of the process very complex. -Requires 20+ enzymes and accessory proteins -Extremely rapid - prokaryote 500 nucleotides added per second - humans 50 nucleotides added per second -Accurate - About 1 in a billion chance of a mistake!!Slide 34Slide 35Where it starts The DNA strands are separated by an enzyme called helicase to form a replication “bubble.”---Replication forks are the Y-shaped regions of replicating DNA molecules where new strands are growing.synthesis of the new strands -DNA polymerase -synthesis occurs in 5' => 3' direction -therefore synthesis is bidirectionalSlide 39Slide 40Slide 41Slide 42Slide 43Slide 44Chapter 11Nucleic Acids: Information storage and transmission.---Genes are the units of heredity and are made of nucleic acid (DNA).---Nucleic acids are polymers of nucleotides linked together by dehydrationsynthesis reactions.3 phosphate groupssugarATPnitrogen-containing base---Nucleotides are the building block molecules of a nucleic acid and are composed of a sugar, a phosphate group, and a nitrogenous base.The sugar and phosphate groups form the nucleic acid backbone.Nucleic acid backbone has directionality (3' versus 5')If DNA were compared to a book, the sugar and phosphate groups would only be the binding of the book. The actual words, or genetic information would be contained in the nitrogenous bases. There are two families of nitrogenous bases:Pyrimidines and Purines---Pyrimidines are nitrogenous bases characterized by a six-membered ring made up of carbon and nitrogen atoms.sugarphosphatebase = cytosine sugarphosphatebase = thymine Fig. 11.3---Purines are nitrogenous bases characterized by a five-membered ring fused to a six-membered ring where both rings are made up of carbon and nitrogen atoms.sugarphosphatebase = adeninesugarphosphatebase = guanineFig. 11.3Evidence that DNA is the genetic material:-During cell division the doubled DNA is divided equally between the two daughter cells-In a eukaryotic cell, the DNA content doubles prior to cell divisionIn 1947, Erwin Chargaff from Columbia University used paper chromatography to separate the bases of the DNA from different species (fish, humans, bacteria, etc.)-Found that the base composition (number of As, Ts, Gs, Cs) varied between species-There was a relationship between the basesChargaff’s rulesA = TG = CAdenine (A) = Thymine (T)Guanine (G) = Cytosine(C)Watson and Crick (and others) discovered the double helixRemember the structure of the monomer (nucleotide) and the polymer (single strand DNA).Rosalind Franklin1920-1958Gifted x-raycrystallographerUnderstanding the structure of DNA-Physical structure evidenceLead to the double helix modelFig. 11.5-2 strands are antiparallel-specific-base pairing complementary base pairs the key to solving puzzle=> A-T and G-C pairs, explained Chargaff's rulesDNA length•DNA in a typical human cell is about 2 meters long.•Must be contained within a cell about 10 µm in diameter•So…in American units…..if the average cell were an inch in diameter, the DNA contained inside of it would be about 3 miles long.Genes•The Human Genome Project revealed that most of the DNA of humans does not encode mRNAs or any other RNAs. Appear to serve no purpose whatsoever in our life cycle.•Accounts for an astonishing ~98.5 % of human chromosomal DNA. •These non-coding regions are similar in humans, but not identical. Accounts for your DNA fingerprint. Called mini-satellite sequences.Mini-satellite sequences:• Red nucleotides represent sequence differences between people.• Now used to “fingerprint” an individual.Single nucleotide difference in sequence between individuals of the same species.DNA evidence is used to “Fingerprint” People with Different Mini-SatellitesForensic DNA Analysis•Became commercially available in 1987.•Since then, there have been thousands of people who have avoided wrongful accusation of crimes. Over 200 rulings have been overturned due to DNA analysis.•Called the “DNA 200”. Group of unjustly imprisoned people who served, on average, 12 years in prison.Recombinant DNA•The combination of DNA from 2 or more organisms into a single DNA molecule.•This is how many important proteins such as insulin, HGH, and EPO are commercially produced today.Insulin•The gene that encodes for insulin production in humans is snipped out of human DNA and inserted into the DNA of an E. Coli bacterium.•These bacteria reproduce extremely quickly, and the new generations of bacteria all produce insulin in enormous quantities.•This is the insulin that diabetics inject on a daily basis. First genetically engineered drug approved by the FDA in 1982.Human Growth Hormone (HGH)•Produced by the human pituitary gland. Insufficient production of HGH leads to dwarfism.•HGH increases protein synthesis, burning of body fat, and growth in nearly every part of the body. Used to combat weight loss in AIDS patients.Human Growth Hormone (HGH)•Before 1994, treatment was extremely expensive because HGH had to be extracted and purified from the pituitary gland of human cadavers. •Through recombinant DNA discoveries, it is now available for the low low price of only $7500 for a month’s supply.Erythropoietin (EPO)•Hormone produced by the kidney that stimulates red blood cell production. •It is used to treat anemia resulting from chemotherapy, eating disorders, and lung disease. •Increases the body’s ability to transport oxygen to cells and
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