1. Goal for Today:
Identify the structure and function of DNA

2. DNA
The letters stand for deoxyribonucleic acid

3. Scientists
James Watson & Francis Crick discovered the structure of DNA

4. Structure of DNA Twisted ladder / double helix
Made of components (monomers) called “nucleotides”
A nucleotide includes a nitrogen base, a five carbon sugar & a phosphate group

6. Structure of DNA
The sides (backbone) of the ladder are alternating sugar and phosphate molecules
The “rungs” are made up of 2 nitrogen bases
The bases are connected to the sugar

8. Nitrogen Bases There are 4 nitrogen bases Adenine (A) Guanine (G)
Cytosine (C)
Thymine (T)

9. Chargoff’s Rule
Any species contains equal amounts of adenine(A) and thymine(T) and also equal amounts of guanine(G) and cytosine(C)…..SO…..

10. A only pairs with T
C only pairs with G
They are connected by hydrogen bonds in the middle of the molecule

11. Brainpop
With quiz!

12. Chromosomes are made of long strands of DNA(each chromosome is a single DNA molecule)
DNA makes up genes
DNA controls the production of proteins
Proteins determine traits

15. Different genes produce different proteins
*the human genome has 3 billion bases and 20,000 genes

16. Proteins
Three nitrogen bases ( or 3 letters) make up a codon (a.k.a. triplet)
One codon makes up one amino acid
Several ( 2-?) amino acids make up one protein
Proteins code for traits

17. Instructions for Paper DNA Model
Guanine – Green
Cytosine – Blue
Thymine – Orange
Adenine – Red
Phosphate – Purple
Deoxyribose – Yellow
Cut out the nucleotides and then paste them on the construction paper

18. Cell Reproduction
For a living thing to grow, it has to make new cells to get bigger
It will go thru several mitotic divisions

19. Thru each division, an exact copy of a cell will be made
The DNA is constantly being copied in the process of…

20. Replication