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Problem 1a
How were scientists able to determine that DNA, and not some other molecule, serves as the genetic material in bacteria and bacteriophages?
Problem 1b
How do we know that DNA also serves as the genetic material in eukaryotes such as humans?
Problem 1c
How was it determined that the structure of DNA is a double helix with the two strands held together by hydrogen bonds formed between complementary nitrogenous bases?
Problem 1d
How do we know that G pairs with C and that A pairs with T as complementary base pairs are formed?
Problem 2
Most center around DNA and RNA and their role of serving as the genetic material. Write a short essay that contrasts these molecules, including a comparison of advantages conferred by their structure that each of them has over the other in serving in this role.
- Discuss the reasons proteins were generally favored over DNA as the genetic material before 1940. What was the role of the tetranucleotide hypothesis in this controversy?
Problem 3
- Contrast the contributions made to an understanding of transformation by Griffith and by Avery and his colleagues.
Problem 4
- When Avery and his colleagues had obtained what was concluded to be the transforming factor from the IIIS virulent cells, they treated the fraction with proteases, RNase, and DNase, followed in each case by the assay for retention or loss of transforming ability. What were the purpose and results of these experiments? What conclusions were drawn?
Problem 5
- Why were ³²P and ³⁵S chosen for use in the Hershey–Chase experiment? Discuss the rationale and conclusions of this experiment.
Problem 6
- Does the design of the Hershey–Chase experiment distinguish between DNA and RNA as the molecule serving as the genetic material? Why or why not?
Problem 7
- What observations are consistent with the conclusion that DNA serves as the genetic material in eukaryotes? List and discuss them.
Problem 8
- What are the exceptions to the general rule that DNA is the genetic material in all organisms? What evidence supports these exceptions?
Problem 9
Problem 10
Draw the chemical structure of the three components of a nucleotide, and then link the three together. What atoms are removed from the structures when the linkages are formed?