Download 1928: Frederick Griffith

History of DNA and DNA Replication Notes
1928: Frederick Griffith discovered_______________________: when a harmless bacteria strain changes
permanently into the disease-causing strain).
Griffith Hypothesized: a “_____________” (______________________________) must contain information
that could change harmless bacteria into disease-causing ones.
Oswald Avery repeated Griffith’s work to determine ________________________ was most important for
transformation.
Oswald Avery & other scientists concluded ______ was the “transforming factor.”
Avery and other scientists discovered DNA __________________________ genetic information from one
generation to the next.
Alfred Hershey and Martha Chase studied viruses grown in cultures ________________
_______________________of phosphorus-32 (32P) and sulfur-35 (35S).
Bacteriophages: viruses that _______________bacteria. composed of a ___________
___________core and a protein coat
Hershey & Chase concluded the ___________________of bacteriophage was DNA, not
____________
Chargaff's Base Pairing Rules:
_____ guanine [G] and cytosine [C] are almost equal in any sample of DNA.
_____ adenine [A] and thymine [T] bases are almost equal in any sample of DNA.
_____________________________used X-ray diffraction to get information about the structure of DNA
James Watson & Francis Crick: __________________of DNA explaining how DNA carried & copied
information.
Double helix: two strands wound around each other like a ___________________________shape.
Hydrogen bonds: relatively weak chemical forces that _______the two strands of the helix to ___________
The ability of the two strands to separate is_______________ to DNA’s functions.
Base pairing: the principle that hydrogen bonds_________________________________________________
______________________________— adenine and thymine, and guanine and cytosine.
Replication: when DNA makes an ______________________of itself before mitosis.
The DNA molecule ________________into two strands, then produces two ________
_________________________________________
How Replication Occurs
DNA replication is carried out by _______________that “unzip” a molecule of DNA.
Helicase: __________ the double helix
DNA polymerase: creates _____________________strand
Hydrogen bonds between base pairs are ______________& the 2 strands of DNA_________.
Draw and label the replicating DNA “fork”: