Popular in Genetics Lecture
Popular in Biology
This 2 page Class Notes was uploaded by Katlyn Burkitt on Tuesday September 27, 2016. The Class Notes belongs to BIOL 309 at Towson University taught by Dr. Bulmer in Fall 2016. Since its upload, it has received 9 views. For similar materials see Genetics Lecture in Biology at Towson University.
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Date Created: 09/27/16
Chapter 9 Lecture Sep 21 Genetics Needed Characteristics for hereditary material Must have a code that can be expressed (Has a genotype for the phenotype) Must be able to replicate itself accurately Must be a small margin of error in the replication process to allow evolution to occur Experimental evidence for DNA being the coding material Bacterial colonies o IIIS = Polysaccride coat o Griffiths transforming agent Take IIIS boiled = Mouse survives IIR alive = Mouse survives IIIS alive = Mouse dies IIR alive + IIIS dead = Dead mouse Transfoming agent is likely DNA because protein would have become denatured This experiment was repeated to ensure the mice had no role Then it was repeated again with the introduction of Protienase, RNAse, and DNase , and only the DNase destroyed the transformation agent o Heinz Fraenkel- Conrat et al Showed that RNA is the genetic material for some viruses Created mixed viruses with protein from one type and RNA from another Established that RNA is the important component in some viruses Basic components of DNA Phosphate, deoxyribose, bases o Purines: Double ring bases o Pyrimidine: Single ring bases 5’ (P) -> 3’(OH) is the direction the DNA moves Chargaff’s rule: That the percentage of A & T and C&G is the same Twist of ladder (DNA) to the right o Double helix o Antiparallel o Complementary base pairing Can “unzip” to form template for replication Each chromosome matches a piece of DNA when being examined through electrophoresis September 23, 2016 DNA Packing Problem o 3 billion nucleotides in a human cell o Al 46 DNA strands lined up end to end measure 2 meters o First step Major protein in chromatin = Histones (H1, H2A, H2B, H3, H4) they are positively charged and interact with negative DNA. Rich in positively charged amino acids (Lysine & Arginine) Histones and DNA form the nucleosome Nucleosomes packed into solenoid fibers by H1 which helps to stabilize them, forms fibers of 30nm in width Scaffold (protein) creates the shape for chromosomes (organizes the solenoids) ******Picture on phone of Math problem******* o The Encyclopedia of DNA Elements (Encode) Project to determine the function of the 98.8% of the unexplored human genome (only 1.2% codes for proteins) 80% of the genome is associated with biological activity Regulatory RNAs- MicroRNA’s Transposons: possibly half of our genome, they can replicated themselves and “jump” to other portions and expand the genome Baggage in the genome from viruses that infected our ancestors (8% is estimated to be decayed retroviruses) o DNA Replication Requirements of Genetic Material Replicates accurately Carries all information for the cell (multicellular) phenotype Capable of occasional mutations (Mispairing of Bases) Semiconservative Where it unzips and each is a template Meselson and Stahl Experiment o E. Coli are allowed to grow in the presence of 15N-Thymidne to make heavier DNA o Create a density gradient with cesium chloride through centrifugation, this results in the heavy and light DNA separate in the tube o ******Picture in cell phone***** takes away the conservative possibility Replication occurs at the Ori (Origin of Replication) 1 Ori/bacterial chromosome Several Ori sites/Eukaryotic chromosomes Ori sties are A-T Rich and more easily denature o DNA Polymerization DNA synthesis has a requirement for A 3’ -OH group A template *******Picture in phone*******
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