Download Genes are Made of DNA

Biology
Notes
Name______________________
Date_____________Hour______
Genes are Made of DNA
DNA can act as a Transforming Factor
 ___________________________ are bacteria that grow in a host, like a mouse or in a culture.

In 1928, Fredrick Griffith studied 2 types
o
o

____________ have a smooth surface and can _________ a mouse within a few days.
____________ have a rough surface and do not really harm the mouse.
To summarize the results:
Type of Bacteria Injected
Fate of the Mouse
Live S strain
Live R strain
Heat treated S strain
Heat treated S strain and R strain

He concluded that
____________________________________________________________________________
____________________________________________________________________________

Based on these results, in 1944 Oswald Avery continued this study by isolating the now living S
strain bacteria from the mouse that had died. (Something had caused the R strain to transform
into the deadly S strain.)
o At the time most scientists knew that this factor had to be either DNA or protein because
chromosomes are made of both DNA and protein. To summarize the results:
Type of Enzyme
Result
Protein destroying enzyme
The R strain ________ transform into the S strain
DNA destroying enzyme
The R strain _______ transform into the S strain.

He concluded that
____________________________________________________________________________
Virus Experiment Provide More Evidence
 In 1952, Alfred Hershey and Martha Chase devised an experiment to determine if the genetic
material was indeed DNA or protein.
 They experimented with bacteriophages (phages) which are viruses that infect bacteria. Label the
phage below with the following words: DNA, Protein Coat, and Tail
 After the phage injects the genetic material into a bacteria, the cell will ____________________
_______________________________________________________________________________

To summarize their results:
Type of Molecule ‘Marked’
Location of Radioactive
Atoms After Infection
Conclusion
Proteins Are Marked
(Phages are grown with
radioactive sulfur and
incorporate these radioactive
atoms into their proteins)
DNA Is Marked
(Phages are grown with
radioactive phosphorus and
incorporate these radioactive
atom into their DNA)
 Alfred Hershey and Martha Chase were able to conclude that____________________________
________________________________________________________________________________
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