1. Forensic DNA Analysis
Introduction to DNA

2. The Cell Smallest unit of life Compose all living things
The “nucleus” (one of many organelles) contains genetic information the cell needs to exist and reproduce
- most cells organize genetic information into chromosomes

3. Chromosomes
our body’s way of organizing all the information that our genetic material contains
23 pairs in humans
- each pair contains one from mother and one from father

4. Genes
Each chromosome contains 100s to 1000s of information blocks called genes
Each gene is the blueprint for a specific protein in the body
- may tell our body what color our eyes are supposed to be, dozens of proteins are responsible for synthesis of ATP, digesting food, etc, etc etc

5. DNA
Each chromosome and every gene is made of deoxyribonucleic acid (DNA)
DNA is a polymer of repeating units called nucleotides
Each nucleotide contains three parts
- phosphate group
- sugar (deoxyribose)
- nitrogenous base

6. The nitrogenous base is always one of four molecules:
Nucleotides
Phosphate Sugar
The nitrogenous base is always one of four molecules:
adenine
guanine
cytosine
thymine

7. The DNA Backbone
Nucleotides are liked together with alternating P-S-P-S-P……..

8. The DNA Double Helix DNA is normally double stranded
The two nucleotide chains are held together by hydrogen bonds
A always pairs with a T on the other strand; C always pairs with G

9. The DNA Double Helix
The two strands wrap around each other to form helical structure shown (double helix)

10. Functions of DNA Two Types of DNA Two primary functions
- transmit information from one generation to the next
- provide blueprint for making proteins the same way every time
Two Types of DNA
nuclear or chromosomal DNA (inherited from mother and father)
mitochondrial DNA (inherited from mother only)

11. DNA Replication DNA is unwound
An enzyme called DNA Polymerase adds complementary bases to “single stranded”
- A with T
- C with G

12. Restriction Enzymes Enzyme that cuts DNA at specific sequences
Recognize and binds to 6-8 nucleotide stretch

13. Gel Electrophoresis Gel with different sized pores
agarose and acrylamide are common materials
Load DNA samples into wells at top of gel
Run electric current through the gel
DNA moves due to negative charge
Smaller bands run “faster”