1. 8.2 – 8.3 Notes
Reaves

2. What is DNA?
Deoxyribonucleic acid is a molecule that carries most of the genetic instructions used in the development, functioning and reproduction of all known living organisms and many viruses.

3. Structure of DNA DNA is composed of four types of nucleotides.
The small units, or monomers, that make up DNA.
Each nucleotide has three parts.
A phosphate group.
A ring-shaped sugar called deoxyribose.
A nitrogen-containing base.
The four types of nucleotides only differ in their nitrogen- containing bases.
One molecule of human
DNA contains billions of nucleotides.

4. Structure of DNA
P 230

5. Structure of DNA Chargaff’s Rules: A = T C = G
Watson and Crick’s DNA model.
double helix – two strands of DNA wind around each other like a twisted ladder
The strands are complementary – they fit together and are the opposite of each other.
- DNA nucleotides of a single strand are joined
together by covalent bonds that connect the
sugar of one nucleotide to the phosphate of the
next nucleotide.
Chargaff’s Rules:
A = T
C = G

6. Structure of DNA

7. DNA Replication Replication copies the genetic information.
Replication – the process by which DNA is copied during the cell cycle
Which phase of the cell cycle does this occur?
assures that every cell has a complete set
of identical genetic information

8. DNA Replication DNA only carries information.
Enzymes and other proteins do all the work of replication.
DNA polymerases –
bond the new nucleotides together
Think Polident – bonds dentures to gums.

9. DNA Replication Process
P 236 – Rewrite in your words.

10. DNA Replication Process
existing molecule
unzipping
nucleotides added
two DNA molecules formed
Read p 238