Chapter 12-1 Part 2

1
Chapter 12-1 Part 2
2
II. Avery (1944)

• Wanted to determine what
• type of molecule was
• responsible for the
• transformation, the molecule
• that makes up genes.
• B. Repeated Griffiths
• experiments
• C. Made an extract (solution) of heat killed
  smooth bacteria and rough bacteria

3

• D. Added 5 different enzymes to the bacteria
  extract (enzymes that destroy different organic
  compounds)
• 1. Bacteria Extract Protein destroying
  enzymes
• transformation occurred (mouse alive
  or dead?)
• 2. Bacteria Extract Lipids destroying
  enzymes
• transformation occurred (mouse alive or
  dead?)
• 3. Bacteria Extract Carb destroying
  enzymes
• transformation occurred (mouse alive
  or dead?)
• 4. Bacteria Extract RNA destroying
  enzymes
• transformation occurred (mouse alive
  or dead?)
• 5. Bacteria Extract DNA destroying
  enzymes
• transformation DID NOT OCCUR (mouse alive or
  dead?)

4

• E. Avery's Conclusion- DNA was the Transforming
  factor.

5
III. Hershey and Chase (1952)

• Wanted to know if genes were made of
• proteins or DNA?
• B. Used bacteriophages (phages)- a type of
  virus that attack bacteria.
• 1. Phage injects its genetic material
  into bacteria and uses the cell to
  reproduce more phages
• 2. Kills bacteria cell- releasing
  hundreds of phages

6

• C. Used radioactive markers
• 1. sulfur 35
• 2. phosphorus 32
• Remember what elements are in
• A. proteins?
• B. Nucleic Acids ( DNA)?

C, H, O ,N , S
C, H, O, N, P
7
(No Transcript)
8

• D. Mixed
• 1. Bacteria phages with either a) Sulfur
  or b) Phosphorus
• Found radioactivity in bacteria with the phage
  DNA injected was from
• 
  phosphorus only.
• E. Hershey and Chases conclusion
• Genes of phages are made of DNA not
• proteins.

http//nortonbooks.com/college/biology/animations/
ch12a02.htm