History of DNA

Question 1

Griffith’s experiements

Answer 1

• experiments with pneumonia causing bacteria
• discovered that when the two cultures were mixed, somehow the harmless bacteria had changed
• he injected the two strains in mice
• first test resulted in the mice living that got the harmless strain, and the other mice died
• he then tested a heat treated form of the disease caring strain. the mice lived
• he then injected the heat treated form and the harmless form and the mice died

Question 2

transformation

Answer 2

• process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

Question 3

Avery’s experiments

Answer 3

• repeated Griffith’s experiments
• he started elimination different parts of the bacteria to see what material actually held the instructions for the cell
• he tested proteins, lipids, carbohydrates, and nucleic acids (DNA)
• when the DNA was destroyed transformation did not occur
• this lead to the understanding that the DNA of the cell help the genetic information (instructions)

Question 4

Hershey and Chase

Answer 4

• studied bacteriophages (virus that infects and kills bacteria)
• used radioactive markers to determine which part of the bacteriophage infects a cell
• after cells were infected they looked to see if the marked proteins or the marked DNA were present
• the DNA was present

Question 5

results

Answer 5

• organisms contained information that could be passed on to another organism
• DNA stores and transmits genetic information
• genes are made form DNA
• until this point we did not know how organism were sending information from one generation to the next