3.1 DNA Structure and Evidence as Genetic Material Flashcards
What year did it become clear that DNA was the basis for an individuals genetic make up?
1944
What are some “things” that do not have DNA as that basic building block of existence?
unique viruses
Who discovered the structure of DNA and when?
Watson and Crick; 1953
What did Watson and Crick determine about DNA structure?
double-helical structure comprised of two strands of DNA containing long chains of nucleotides
When did Watson and Crick win the Nobel Prize?
1962
When was DNA actually discovered and by whom?
1869; Miescher
What did Miescher identify?
nuclein within the nuclei of human white blood cells
What was Levene’s theory and what was the year?
1910; DNA contains equal amounts of four molecules called nucleotides which are present in repetitive and equal amounts in DNA
What was Levene wrong about?
that nucleotides were repetitive and in equal amounts
What are the four characteristics that the genetic flow of material between organisms is dependent on?
- replication of materials
- storage of information
- expression of information
- variation through mutations
How is genetic material doubled and passed along?
division of daughter cells (mitosis) and gametes (meiosis)
Where is genetic material stored?
nucleus
What are sources of variation within a population?
mutations
What did Griffith note in his experiments and when?
1927; some strains of D. pneumoniae were virulent and some were not
What determined virulence in Griffith’s experiment?
virulent strains contained a polysaccharide capsule while avirulent did not
What did the capsule do in Griffith’s experiment?
protected the virulent strains from being engulfed by phagocytic immune cells in the host’s circulatory system
When plated on agar plates, what did the virulent and avirulent strains of Griffith’s experiment produce?
virulent = shiny, smooth colonies
avirulent = rough colonies
What two serotypes did Griffith use in his experiment?
IIR = rough, no capsule, avirulent
IIS = smooth, capsule, virulent
What were the three things Griffith noted in his experiment?
- injecting live avirulent IIR into mice produced no disease
- injecting heat-killed virulent IIIS into mice produced no disease
- injecting live avirulent IIR WITH heat-killed IIIS killed all the mice
What process did Griffith discover with his experiment with D. pneumoniae?
transformation
