Question

Name: Date: Section: Biology 190: Introduction to Cdl and Molecular Biolog Reading guide # 16 Ch.-DNA Structure & Replication Read p. 257-273 from Cha dar the following question Prior to Watson and Crick's deduction of DNA structure, the parad that protein and not DNA was the molecule that was the likely genetic mate candidate at the time? on of DNA structure, the paradigm among the scientific community was Necule that was the likely genetic material. Why was protein a stronger 2. Match the following investigars with their scientific discoveries that paved the way to determining DNA as the genetic material and Watson and Crick's deduction of DNA structure in 1953. Investigators (Year) _ Frederick Griffith (1928) A Scientific Discovery Purified DNA and protein from heat-killed S cells and determined that DNA, not protein, could transform the R-cells. Generated X-ray diffraction data used by Watson and Crick to deduce the structure of DNA, got screwed out of a Nobel Prize after dying of cancer. _Avery, McLeod & McCarty (1944) B Erwin Chargaff (1949) C Observed that mixing heat-killed pathogenic strains (S cells) of pneumococcal bacteria with innocuous strains (R cells) could convert some of the innocuous strains into pathogenic strains, thereby killing mice that had been injected with this mixture. D Observed a 1:1 ratio of A:T and G:C in nucleic acids. _Hershey and Chase (1952) Rosalind Franklin (1952) E Used bacteriophages and the fundamental knowledge that DNA contains phosphorous while protein contains sulfur to determine that DNA and not protein was the genetic material transferred from bacteriophage to bacteria. 3. Elaborate further on Hershey & Chase's experiment by describing HOW they came to determine that DNA and not protein was the genetic material of T2 bacteriophage.

Answer 1

Answer 1 Protein considered as a strong candidate as genetic material because most of the body or cell is made up of protein also protein causes many signalling in cell.

Answer 2. Frederick Griffith = observed that mixing heat killed pathogenic strain (S cells) of pneumococcal bacteria with innocuous strain (R cells) could convert some of the innocuous strain into pathogenic strain, thereby killing of mice that had been injected with this mixture.

Avery, McLeod and McCarty = purified DNA and protein from heat killed S cell and determined that DNA, not protein could transform the R cells.

Erwin Chargaff = observed a ratio of 1:1 of A:T and G:C in the nucleic acid.

Hershey chase = used bacteriophage and fundamental knowledge of the DNA that contain phosphorus while protein contain sulfur to determine that DNA not protein was the genetic material transferred from bacteriophage to bacteria .Rosalind franklin = Generated X- ray diffraction data used by Watson and Crick to deduced the structure of DNA, got screwed out of Noble prize after dying of cancer