Download Chapter 12 Section 1

Chapter 10-1 and 10-2
DNA
Warm-Up
Pair the scientist with their discovery or project
Scientist
Discovery/Project
Avery
Bacteriophages genetic information is
carried by DNA
Franklin
DNA stores and transmit genetic information
Griffith
Structure of DNA and principle of base
pairing
Hershey &
Chase
Transformation
Watson & Crick
X-ray of the structure of DNA
Scientist
Discovery/Project
Avery
Bacteriophages genetic information is carried by
DNA
Franklin
DNA stores and transmit genetic information
Griffith
Structure of DNA and principle of base pairing
Hershey & Chase
Transformation
Watson & Crick
X-ray of the structure of DNA
Scientist and their DNA
Discoveries

Griffith - 1928
Transformation
 Studied pneumonia in mice


Avery – early 1940’s
Repeated Griffith’s experiment in order to
find out what molecule was most
important in transformation
 Found that the nucleic acid DNA stores
and transmits genetic information

Continued….

Hershey-Chase - 1952

Bacteriophages



Wanted to determine if the protein or DNA core of
bacteriophages entered the infected cell which in turn
would tell them what carried the genetic information
Conclued that genetic information of the bacteriophage
was DNA
Chargraff - 1949

Percentage of guanine and cytosine are almost
equal in any sample of DNA as are adenine and
thymine
Continued….

Franklin

Used x-ray diffraction to get information
about the structure of DNA
 Showed
that the x-shaped pattern of DNA are
twisted in a helix
 Suggested there are 2 strands in DNA and that
the bases are near the center of DNA

Wilkins

Produced x-ray idffracton photographs and
crystal of DNA
Continued….

Watkins and Crick -1950s
Constructed the double-helix model of
DNA
 Discovered the principle of base pairing

Video Clip
The Components and Structure
of DNA

3 critical things genes do:
1.
2.
3.
Carry information from one generation to
the next
Determine the heritable characteristics of
organisms
Easily copied
Structure of DNA
5-carbon sugar (deoxyribose) and a
phosphate group made up of a
phosphorus atom bonded with 4
oxygen atoms make up the backbone
 Nitrogenous bases make up the rungs
and contain nitrogen and carbon
atoms. It is a base which will accept
hydrogen ions.

Made up of nucleotides
4 Types of Bases

Purines

2 rings of carbon
and nitrogen

Pyrimidines

1 ring of carbon and
nitrogen
DNA Structure
Base Pairing Rule
for DNA:
A-T
C-G
The order of
nitrogenous bases on
a chain of DNA is
called its base
sequence.
Bonds of DNA
Nucleotides are connected by covalent
bonds between the sugar of one and
the phosphate of the next.
 Hydrogen bonds form between the
complementary bases.

2 hydrogen bonds between A and T
 3 hydrogen bonds between C and G
