Textbook QuestionWhat results from the experiments of Frederick Griffith provided the strongest support for his conclusion that a transformation factor is responsible for heredity?263views
Textbook QuestionIn this chapter, we first focused on the information that showed DNA to be the genetic material and then discussed the structure of DNA as proposed by Watson and Crick. We concluded the chapter by describing various techniques developed to study DNA. Along the way, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions: How do we know that DNA also serves as the genetic material in eukaryotes such as humans?178views
Textbook QuestionIn this chapter, we first focused on the information that showed DNA to be the genetic material and then discussed the structure of DNA as proposed by Watson and Crick. We concluded the chapter by describing various techniques developed to study DNA. Along the way, we found many opportunities to consider the methods and reasoning by which much of this information was acquired. From the explanations given in the chapter, what answers would you propose to the following fundamental questions: How were scientists able to determine that DNA, and not some other molecule, serves as the genetic material in bacteria and bacteriophages?245views
Textbook QuestionExplain why Avery, MacLeod, and McCarty's in vitro transformation experiment showed that DNA, but not RNA or protein, is the hereditary molecule.343views
Textbook QuestionHershey and Chase selected the bacteriophage T2 for their experiment assessing the role of DNA in heredity because T2 contains protein and DNA, but not RNA. Explain why T2 was a good choice for this experiment.205views
Textbook QuestionDiscuss 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?403views
Textbook QuestionExplain how the Hershey and Chase experiment identified DNA as the hereditary molecule.253views
Textbook QuestionContrast the contributions made to an understanding of transformation by Griffith and by Avery and his colleagues.254views
Textbook QuestionWhen 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?255views
Textbook QuestionGiven the state of knowledge at the time of the Avery, MacLeod, and McCarty experiment, why was it difficult for some scientists to accept that DNA is the carrier of genetic information?453views
Textbook QuestionWhy were ³²P and ³⁵S chosen for use in the Hershey–Chase experiment? Discuss the rationale and conclusions of this experiment.265views
Textbook QuestionDoes the design of the Hershey–Chase experiment distinguish between DNA and RNA as the molecule serving as the genetic material? Why or why not?404views
Textbook QuestionWhat observations are consistent with the conclusion that DNA serves as the genetic material in eukaryotes? List and discuss them.391views
Textbook QuestionWhat are the exceptions to the general rule that DNA is the genetic material in all organisms? What evidence supports these exceptions?471views
Textbook QuestionDescribe the various characteristics of the Watson–Crick double-helix model for DNA.201views
Textbook QuestionWhat evidence did Watson and Crick have at their disposal in 1953? What was their approach in arriving at the structure of DNA?368views
Textbook QuestionHow is the absorption of ultraviolet light by DNA and RNA important in the analysis of nucleic acids?318views
Textbook QuestionAlbinism, an autosomal recessive trait characterized by an absence of skin pigmentation, is found in 1 in 4000 people in populations at equilibrium. Brachydactyly, an autosomal dominant trait producing shortened fingers and toes, is found in 1 in 6000 people in populations at equilibrium. For each of these traits, calculate the frequency of the recessive allele at the locus237views
Textbook QuestionA primitive eukaryote was discovered that displayed a unique nucleic acid as its genetic material. Analysis provided the following information: A major hyperchromic shift is evident upon heating and monitoring UV absorption at 260 nm.213views
Textbook QuestionA primitive eukaryote was discovered that displayed a unique nucleic acid as its genetic material. Analysis provided the following information: The general X-ray diffraction pattern is similar to that of DNA, but with somewhat different dimensions and more irregularity.288views