DNA & Gel Electrophoresis

Sci VisII HNV205.05

E.Q: How can I use animation Techniques to construct DNA & Gel Electrophoresis?

_Read pg:100-110 on Student Master Notes

_Take notes on DNA_Plan for the project_Go over the rubric

The Structure of DNA

DNA• Deoxyribonucleic acid• Large molecule called a

polymer– Polymer means

molecule with many units

• Units or monomers of DNA are nucleotides

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

Purine Bases

• Adenine and guanine• The larger of the 2 types of

bases• Have a double ring

structure

Adenine

Guanine

Pyrimidine Bases

• Cytosine and Thymine• Have a single ring structure

Cytosine

Thymine

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.

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

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.

DNA Fingerprinting

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

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

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

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

Uses of fingerprinting

• Discovery of genetic causes of diseases

• Mapping the human genome (2003)

• Forensic science• Paternity testing

References

• Adenine and guanine - http://www.chemsoc.org/networks/learnnet/cfb/nucleicacids.htm

• Thymine and cytosine - http://www.chemsoc.org/networks/learnnet/cfb/nucleicacids.htm

• dAMP & dCMP - http://www.cancerwatch.org/glossary/glossary_7.cfm

References

• Double helix - http://alum.mit.edu/ne/opendoor/200507/images/double-helix.jpg

• A&T logo – www.ncat.edu• UNCG logo – www.uncg.edu