Chapter 10 DNA Structure and Analysis-Questions and Answers 100% Correct

Chapter 10 DNA Structure and Analysis-Questions and Answers 100% Correct What four general characteristics must the genetic material possess? - ANSWER-1. Replication: The processes of mitosis and meiosis 2. Storage of information: Storing the complete DNA component vs gene expression 3. Expression of stored information: The "central dogma of molecular genetics" 4. Variation through mutation (gametes) Briefly outline the history of our knowledge of the structure of DNA until the time of Watson and Crick. - ANSWER-1869: Johann Friedrich Miescher isolates nuclei from white blood cells and extracts a substance that was slightly acidic and rich in phosphorous. He calls it nuclein. Late 1800s: Albrecht Kossel determines that DNA contains the four nitrogenous bases: adenine, guanine, cytosine, and thymine. 1920s: Phoebus Aaron Levine discovers that DNA consists of repeating units, each consisting of a sugar, a phosphate, and a nitrogenous base. 1950: Erwin Chargaff formulates Chargaff's rules (A = T and G = C). 1947: William Ashbury begins studying DNA structure using X-ray diffraction. : Rosalind Franklin, working in Maurice Wilkins's lab, obtains higher resolution pictures of DNA structure using X-ray diffraction techniques. 1953: Watson and Crick propose the model of DNA structure. What experiments demonstrated that DNA is the genetic material? - ANSWER-Experiments by Hershey and Chase in the 1950s using the bacteriophage T2 demonstrated that DNA is the genetic material of the bacteriophage. Also, the experiments by Avery, Macleod, and McCarty demonstrated that the transforming material initially identified by Griffiths was DNA. What is transformation? How did Avery and his colleagues demonstrate that the transforming principle is DNA? - ANSWER-Transformation occurs when a transforming material (or DNA) genetically alters the bacterium that absorbs the transforming material. Avery and his colleagues demonstrated that DNA is the transforming material by using enzymes that destroyed the different classes of biological molecules. Enzymes that destroyed proteins or RNA had no effect on the activity of the transforming material. However, enzymes that destroyed DNA eliminated the biological activity of the transforming material. Avery and his colleagues were also able to isolate the transforming material and demonstrate that it had chemical properties similar to DNA. How did Hershey and Chase show that DNA is passed to new phages in phage reproduction? - ANSWER-Hershey and Chase used the radioactive isotope 32P to demonstrate that DNA is passed to new phage particles during phage reproduction. The progeny phage released from bacteria infected with 32P-labeled phages emitted