1. DNA and RNA

2. DNA and Chromosomes
Prokaryotes do not have a nucleus and their DNA is located in the cytoplasm
They usually have a single circular DNA molecule (a chromosome)

3. DNA and Chromosomes
Eukaryotes are more complex, so they have a nucleus and this is where the DNA is housed
Found as a number of chromosomes which vary between species

4. OBJ: describe the experiments of Watson and Crick and R
OBJ: describe the experiments of Watson and Crick and R. Franklin, which led to the discovery of the structure of the DNA double helix.
History of DNA

5. DNA Replication
Watson and Crick discovered the double helix structure of DNA
this structure explains how the molecule may be replicated
Each strand of the double helix has all of the information required to construct the other strand = complimentary

7. OBJ describe the structure of a nucleotide and list the 4 DNA nucleotides
OBJ describe how nucleic acids are made of long chains of nucleotides

8. Structure of DNA
Long molecule made up of monomer subunits called nucleotides
Each nucleotide is made of three parts:
5-Carbon Sugar
Phosphate group
A Nitrogenous base

9. Sugar-Phosphate Backbone
The outer structure of the DNA molecule
Composed of a 5-Carbon sugar (in DNA it is deoxyribose), and a Phosphate group
The sugar molecules bonds to the nitrogenous bases
The Phosphate groups hold the sugars together

10. Nitrogenous Bases
These are the molecules that bond the two complimentary strands of DNA together
Held together between the two strands by Hydrogen bonds, these are very weak bonds (for breaking)
Can be: Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)
Adenine will always bond with Thymine
Guanine will always bond with Cytosine

11. Nitrogenous Base Pairs

12. OBJ: explain the functions of the main enzymes involved in DNA replication

13. DNA Replication
Separating the two strands allows for new strand to be made following the rules of base pairing
Replication begins at various points on the chromosome and continues until the entire chromosome has been copied

14. Duplicating the DNA Strand
This process occurs before the cell divides, and is called replication (this would be Interphase)
During replication, the DNA separates into two strands, then two new complimentary strands are produced using the rules of base pairing. Each strand of the original serves as a template for the new strand
This process allows each daughter cell to have an exact copy of the parent cell’s DNA

15. How does that happen?
This process is carried out by a collection of enzymes
They “unzip” the DNA molecule (break the Hydrogen bonds between the bases)
DNA Polymerase is the enzyme responsible for assembling the new DNA strands, it also proofreads the new strand to look for errors