1. DNA And protein synthesis
The Structure of the Genetic Material

2. The Structure of the Genetic Material
Experiments that showed that DNA is the Genetic Material
DNA and RNA are Polymers of Nucleotides
DNA is a Double Stranded Helix

3. Experiments that showed that DNA is the Genetic Material –Griffith’s Experiment

4. The Hershey – Chase Experiment
The Hershey – Chase Experiment was final piece of evidence implicating DNA as the genetic material.
It resulted from a experiment on the T2 virus. The T2 virus is a bacteriophage (phage) that infects the bacterium E. coli.

5. How did we find out that it was DNA that carried information?
Use of viruses; bacteriophages (phages) infecting E.coli bacteria
Hershey-Chase experiments

6. DNA and RNA are Polymers of Nucleotides » » » » » » » » »
DNA and RNA polymers are called Polynucleotides.
Monomer
DNA and RNA monomers are called _______.

7. Nucleic acids and their nucleotides
A nucleotide is comprised of:
A sugar
A phosphate
A nitrogenous Base

8. Nucleic acids and their nucleotides
There are four different types of DNA and RNA nucleotides. The Sugar and the phosphate group is the same in all normal DNA nucleotides. This is what makes up the sugar – phosphate backbone in DNA. Covalent. (also true for RNA nucleotides)

9. Nucleic acids and their nucleotides
The four types of DNA nucleotides only differ in their nitrogenous bases. (Same for RNA nucleotides)

10. When nucleotides float in, have 3 phosphates attached (Called nucleoside or ACTIVATED nucleotide) DNA polymerase – detaches 2 phosphates, leaving one still attach to add to sugar-phosphate backbone.

11. Sugars
The sugars of nucleic acids, called pentose sugars, have five carbon atoms, numbered 1′, 2′, 3′, 4′, 5′.
The 5′ carbon is always attached to the phosphate group. (very important)

12. Genetic information

13. Chargaff’s Rule» » » » » » » »

14. Chargaff’s Rule

15. Franklin’s X – Rays

16. Watson and Crick

17. DNA’s Primary structure
DNA’s Primary structure refers to the string of nucleotide linked together.

18. DNA’s Secondary structure
DNA’s secondary structure refers to its three – dimensional configuration or its fundamental helical structure.
The strands run antiparallel in order to allow bases to be in center.

19. DNA Replication

20. Replicating DNA
A huge amount of genetic information and an enormous number of cell divisions are required to produce a multicellular organism; even a low rate of error during copying would be catastrophic.
The solution to this problem is central to replication.
Not only must the copying of DNA be astoundingly accurate but it must also take place at breakneck speeds.

21. Requirements for DNA replication
Enzymes and other proteins that read the template and assemble the DNA molecule
DNA helicase
DNA primase
DNA polymerase
DNA Ligase

22. Requirements for DNA replication
DNA helicase
Unwinds the DNA at the replication fork (area where strands are separated).

23. Requirements for DNA replication
DNA primase Synthesized a short DNA primer to provide a 3′ OH group for the attachment of DNA nucleotides.

24. Requirements for DNA replication
DNA polymerase Creates DNA strand by adding nucleotides. Nucleotides can only be added from a 5′ to 3′ direction of the new strand.

25. Requirements for DNA replication
DNA ligase Joins Okazaki fragments (segments of DNA nucleotides) by sealing nicks in the sugar- phosphate backbone of the newly synthesized DNA. (links fragments)

26. Semi-conservative DNA replication
Watson and Crick= complementary nature of the two nucleotide strands in a DNA molecule suggested that, during replication, each strand can serve as a template for the synthesis of a new strand.
Meselson and Stahl Experiment

27. Semi-conservative DNA replication

28. Modes of replication
There are several different ways in which semiconservative replication can take place depending on the nature of the template and whether it is circular or linear.

29. Eukaryotic DNA replication
The large linear chromosomes in eukaryotic cells have far too much DNA to be replicated speedily from one origin of replication, so they have many.

30. SHOW ME DNA REPLICATION!
Create a DNA double helix of 16 base pairs, using the yellow cards.
Using the cards and chalk showcase each part of the DNA replication process and take a PHOTO before moving on!
Show me photos (in order) by the end of the period!
INCLUDE:
Helicase
DNA polymerase
Activated nucleotides
Nucleotides
Hydrogen bonds