1. The molecule that carries the genetic information in all living things
DNA
The molecule that carries the genetic information in all living things

2. Notes: The Structure of DNA
Before the early 1900’s, scientists did not know the chemical make-up of genes

3. Griffith’s Experiment
Griffith was studying what caused pneumonia. He isolated two types of bacteria from mice (R strain & S strain)
R Strain- harmless bacteria the had rough edges
S Strain- pneumonia causing bacteria that had smooth cultures

4. Bacterial Transformation
Griffith hypothesized that some chemical compound in the heat killed S-strain was transferred into the living R-strain. He called this process transformation

5. What causes Transformation?
Oswald Avery built on Griffith's experiment and treated heat-killed bacteria with enzymes that killed proteins, lipids & RNA and transformation occurred.
When bacteria was treated with enzyme that killed DNA, transformation no longer occurred.

6. Hershey-Chase Experiment Continued
DNA contains phosphorus & protein contains sulfur.
Hershey & Chase used that information to determine which macromolecule carried genetic material.
When the bacteriophage injected its genetic material into the bacteria, phosphorus was found, indicating that DNA was transferred, not protein!
Compare the structure of protein with DNA
DNA is genetic material found in genes

7. DNA made of nucleotides
Deoxyribonucleic Acid (DNA) is a nucleic acid
Nucleic acids are made of subunits called nucleotides

8. Nitrogenous bases DNA bases have nitrogen in them
DNA has 4 different types of bases
Adenine (A)
Guanine (G)
Cytosine (C)
Thymine ( T)

9. Chargaff’s Rule
Biologist Erwin Chargaff found that the percentage of Adenine and Thymine in any sample of DNA was always equivalent. The same with Guanine & Cytosine.
A=T and G=C known as Chargaff’s Rule

10. Rosalind Franklin’s X-ray
Franklin used a technique called X- ray diffraction to obtain the arrangement of the molecules in DNA
The pattern showed a pattern consistent with a helix

11. James Watson & Francis Crick
Watson identified Rosalind's X-ray picture as a double helix.
Watson & Crick model showed that the DNA strands had to run opposite of each other. They were antiparallel.

12. Hydrogen Bonds & Base Pairing
The strands are held together by weak hydrogen bonds. Bonds can only for between Adenine & Thymine and Guanine & Cytosine. This is called base pairing

13. Exit Ticket
Explain how Chargaff’s rule & Rosalind Franklin’s X-ray contributed to the discovery of DNA’s structure.

14. The molecule that carries the genetic information in all living things
DNA
The molecule that carries the genetic information in all living things

15. DNA Replication
Before the cell is able to divide, the DNA has to be copied. This process is called replication. This happens during S-phase in the cell cycle.

16. DNA Replication Process
The hydrogen bonds between base pairs are broken by an enzyme-- DNA Helicase.
Two template strands will be created.

17. DNA Replication Process
Free-Floating nucleotides will be added to the template strand.
DNA polymerase joins nucleotides to the template strand to create the complementary strand

18. DNA Replication Process
DNA Polymerase will also proofreads each strand and check for any errors.
At the end of DNA Replication, two semiconservative strands are created.

19. Telomeres
Repetitive sequences added
Prevents the cells from losing genes.

20. DNA Replication in Prokaryotes
Prokaryotes DNA is circular.
Replication has one starting point and it replicates in both directions until it is complete.

21. DNA Replication in Eukaryotes
Replication can begin in hundreds of places on the DNA molecule in Eukaryotes
The strand will replicate in both directions until replication is complete.

22. Describe the function of each enzyme during DNA replication
Exit Ticket
Describe the function of each enzyme during DNA replication
1) DNA Helicase
2) DNA Polymerase