KA1-DNA Discovery Flashcards
Who discovered the ‘Transforming Principle’?
Griffith
When was the ‘Transforming Principle’ discovered?
1928
What did Griffith work with?
2 bacterial strains; S caused pneumonia in mammals, R was harmless
What did Griffith prove?
That a chemical could be transferred from dead S to live R strain, transforming them into the deadly S strain
What was Avery’s experiment?
Repeating the Griffith experiment but isolating different substances from the S strain and testing their ability to cause the transformation
When did Avery conduct his experiment?
1944
What did Avery discover?
That it was the DNA fragments causing the transformation
When was the Hershey and Chase experiment conducted?
1952
What did Hershey and Chase do?
Test the ability of viral DNA and viral protein coats to alter the host cell’s biochemical machinery
What did Hershey and Chase use in their experiment?
A bacteriophage virus, which attacks E.Coli
What did Hershey and Chase track?
The radioactive molecules to see if they entered the cell or stayed on the outside.
What happens if the bacteriophage is labelled with 35S?
Its protein coat becomes radioactive
What happens if the bacteriophage is labelled with 32P?
It’s DNA becomes radioactive
What did Hershey and Chase discover?
That the labelled DNA entered the cell and was responsible for the production of new viruses
Who discovered the base pairing rule?
Chargaff
