DNA HISTORY
Genetics
DO NOW
Read this quote and write a 3-4 sentence
paragraph explaining how this might relate to
our theme of biology: everything is
interconnected
“A genetic material must carry two jobs:
duplicate itself and control the development
of the rest of the cell in a specific way”
Francis Crick
AGENDA
Do Now
Lab research activity in groups
Go over the discoveries of DNA and their
researchers
Review
Worksheet
NEW THEME OF BIOLOGY
In biology, we now know that everything
is interconnected, but we will also need
to understand that…
Structure dictates function
GRIFFITH
GRIFFITH
 Harmful smooth (s-strain) and harmless rough (R strain) of pneumonia in mice to see which one was
deadly
 Mixed dead S and live R strains= deadly and killed
mouse
 Dead S cells= mouse is alive
 Live R cells= mouse is Alive
 Why?
 Griffith wanted to know WHAT was transferred
between S and R strains?
 DNA!!!!
HERSHEY AND CHASE
HERSHEY AND CHASE
 Wanted to know whether protein or DNA was the
material transferred
 Bacteria and Viruses were used
 Radioactive sulfur and phosphorus were used to
label protein and DNA, respectively
 Found that phosphorus was inside the bacteria,
so they stated that DNA was the genetic material,
NOT protein
LEVENE
 Discovered the different types of sugars present within
RNA and DNA
 Found that DNA has deoxyribose and RNA has ribose
sugars
 Important in knowing the structure of DNA
CHARGAFF
 Discovered the ratios of ACGT within DNA
 Chargaff’s rule: states that there is an even
proportion of A to T and G to C
 A=T
 G=C
FRANKLIN
 Discovered DNA was SYMMETRICAL and regular
 Used x-ray crystallography to discover the
structure
WATSON AND CRICK
Found that A and T go together and G and C.
Deduced the 3D structure of DNA
REVIEW
 What molecule was determined to not be the
carrier of genetic information?
Protein
 What scientists made this discovery? What did
they use to discover this?
Hershey and Chase/ viruses and bacteria
 Who discovered the structure of DNA/RNA
sugars?
Levene
REVIEW
 What is Chargaff’s rule?
There is an even amount of A to T, G to C
 I have 20% adenine. How much of TG and C do I
have?
20% T and 30% G and 30% C
 What did Rosalind Franklin’s discovery show us
about DNA structure?
Symmetrical molecule