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• Opener: What controls all cell activities and determines our features?
Bacteriophage with phosphorus-32 in DNA
Phage infectsbacterium
Radioactivity inside bacterium
Bacteriophage with sulfur-35 in protein coat
Phage infectsbacterium
No radioactivity inside bacterium
Alfred Hershey and Martha Chase’s experimentSection 12-1
Go to Section:
Bacteriophage with phosphorus-32 in DNA
Phage infectsbacterium
Radioactivity inside bacterium
Bacteriophage with sulfur-35 in protein coat
Phage infectsbacterium
No radioactivity inside bacterium
Hershey-Chase ExperimentSection 12-1
Go to Section:
Bacteriophage with phosphorus-32 in DNA
Phage infectsbacterium
Radioactivity inside bacterium
Bacteriophage with sulfur-35 in protein coat
Phage infectsbacterium
No radioactivity inside bacterium
Hershey-Chase ExperimentSection 12-1
Go to Section:
Rosalyn Franklin
Her work was used by James Watson and Francis Crick to figure out the structure of DNA
Percentage of Bases in Four Organisms
Section 12-1
Source of DNA A T G CSource of DNA A T G C
Streptococcus 29.8 31.6 20.5 18.0
Yeast 31.3 32.9 18.7 17.1
Herring 27.8 27.5 22.2 22.6
Human 30.9 29.4 19.9 19.8
Streptococcus 29.8 31.6 20.5 18.0
Yeast 31.3 32.9 18.7 17.1
Herring 27.8 27.5 22.2 22.6
Human 30.9 29.4 19.9 19.8
Go to Section:
Chargaff’s Rule!
James Watson
and
Francis Crick
Purines Pyrimidines
Adenine Guanine Cytosine Thymine
Phosphate group Deoxyribose
DNA NucleotidesSection 12-1
Go to Section:
Hydrogen bonds
Nucleotide
Sugar-phosphate backbone
Key
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
Structure of DNASection 12-1
Go to Section:
DNA ReplicationSection 12-2
Go to Section:
Growth
Growth
Replication fork
DNA polymerase
New strand
Original strand DNA
polymerase
Nitrogenous bases
Replication fork
Original strand
New strand
THE DNA SONG!!
• To the tune of “Row, row your boat”– We love DNA
Made of nucleotides.Sugar, phosphate and a baseBonded down one side.
– Adenine and thymineMake a lovely pair.Cytosine without guanineWould feel very bare.
