1. DNA & Gel Electrophoresis
V205.05

2. The Structure of DNA

3. DNA Deoxyribonucleic acid Large molecule called a polymer
Polymer means molecule with many units
Units or monomers of DNA are nucleotides

4. Nucleotides Made of 5-carbon sugar called deoxyribose
Deoxyribose contain a phosphate group and one of four nitrogen bases
4 nitrogen bases
A for adenine
G for guanine
C for cytosine
T for thymine

5. Purine Bases Adenine and guanine The larger of the 2 types of bases
Have a double ring structure
Guanine

6. Pyrimidine Bases Cytosine and Thymine Have a single ring structure

7. Deoxyribose sugar
3 oxygen and 5 carbon atoms which make up the DNA “backbone”
The hydroxyl groups’ carbons link to phosphates to form this “backbone”
dAMP: Deoxyadenosine monophosphate, a nucleotide containing adenine, a 2'-deoxyribose sugar and phosphate, part of DNA structure.
dCMP: Deoxycytosine monophosphate, a nucleotide containing cytidine, a 2'-deoxy sugar, and phosphate, part of DNA structure.

8. Double Helix DNA is composed of twisting strands of nucleotides
Each strand is a helix or spiral staircase
2 strands are bound together to create a double helix
Double helix

9. Configuration of DNA
A & T always join together and form 2 hydrogen bonds
C & G always join together and form 3 hydrogen bonds
Think A & T and UNCG to remember these.

10. DNA Fingerprinting

11. Definition Method of identification that compares fragments of DNA
DNA is the genetic material found in the cell nucleus
DNA of each individual is unique, with identical twins being the only exception

12. Constructing a Fingerprint
A “fingerprint” is constructed by
Obtaining a DNA sample from body tissue or fluid
Cutting this sample into pieces using enzymes
Arranging these pieces using gel electrophoresis

13. Gel Electrophoresis
Refers to the forced movement of molecules by electricity
Separates macromolecules (large molecules) on the basis of size, electric charge, and other physical properties.
The gel is like Jell-o.
Electrophoresis describes the moving of the charged DNA
Electro: energy of electricity
Phoros: to carry across

14. Steps in Gel Electrophoresis
Holes created in gel to hold DNA solution
DNA solutions loaded into holes
Gel is “excited” by electricity and small molecules move through the gel
Photograph is taken to save the results of the fingerprint
2 matching fingerprints indicate they are probably from identical sources

15. Uses of fingerprinting
Discovery of genetic causes of diseases
Mapping the human genome (2003)
Forensic science
Paternity testing

16. References
Adenine and guanine - eicacids.htm Thymine and cytosine - eicacids.htm dAMP & dCMP -

17. References
Double helix - ouble-helix.jpg A&T logo – UNCG logo –