2. (Deoxyribonucleic Acid) (Deoxyribonucleic Acid)
DNA
(Deoxyribonucleic Acid)
(Deoxyribonucleic Acid)
History and Structure
C10L28C12

3. Chromosomes are made of DNA
Chromosomes and DNA
During Mitosis we can
see Chromosomes
Chromosomes are made of DNA

4. Chromosomes and DNA

5. Today’s Goals Item 1 What is DNA? Item 2 DNA History Item 3
DNA Structure
Item 4
DNA Nitrogen Bases
Item 5
Chargaff's Rule

6. What is DNA?
DNA holds all the genetic information that determines an organism’s traits.
Hair Color
Height
Skin Tone
Eye Color

7. What is DNA?
Within the structure of DNA is the information for life—the complete instructions for manufacturing all the proteins for an organism.
DNA achieves its control by determining the structure of proteins.
Enzymes (a type of protein) control the chemical reactions needed for life.
Eating, running, even thinking

8. Today’s Goals
Item 1
What is DNA?
Item 2
DNA History

9. Johann Friedrich Meischer
1869
The first scientist to identify and isolate DNA
He called it nuclein

10. Important clues to the structure of DNA
Rosalind Franklin
1952
Studied DNA structure with X-ray diffraction
Important clues to the structure of DNA
Twisted strands (helix)
Angle suggested 2 strands ( double-helix)
Nitrogen bases near the center of the molecule

11. James Watson and Francis Crick
1953
Built a DNA model based on the clues from Franklins X-ray diffraction

12. Today’s Goals Item 1 What is DNA? Item 2 DNA History Item 3
DNA Structure

13. DNA is a Double Helix
A double helix looks like a twisted ladder.

14. The Double Helix Building Blocks
A DNA strand is a polymer.
They are very long!
It’s length is what allows DNA
to hold so much information
The repeating subunits
of DNA are called
nucleotides

15. Nucleotide Structure Composed of 3 parts Phosphate Nitrogen Base
There are 4
possible bases.
Broken down into
2 categories
Phosphate
Nitrogen
Base
Deoxyribose
Sugar

16. Nucleotide Structure
The phosphate groups and deoxyribose (sugar) molecules bond to form the backbone of the chain
The nitrogenous bases stick out like the teeth of a zipper.

17. Today’s Goals Item 1 What is DNA? Item 2 DNA History Item 3
DNA Structure
Item 4
DNA Nitrogen Bases

18. Types of Nitrogen bases
There are two types of nitrogen bases
Purines
Pyrimidines
Pyrimadines have one ring
Purines have two rings

19. Types of Nitrogen bases
There are two types of nitrogen bases
Purines
Pyrimidines

20. Today’s Goals Item 1 What is DNA? Item 2 DNA History Item 3
DNA Structure
Item 4
DNA Nitrogen Bases
Item 5
Chargaff's Rule

21. How the double helix is formed
Nitrogen bases bond to one another to connect the two strands
But only certain bases can bond to one another

22. Chargaff’s Rule – Base Pairing
1 Purine must bond to 1 pyrimadine
Adenine only bonds to Thymine
Guanine only bonds to Cytosine
Purines
Pyrimidines At
The
Grand
Canyon