3. Quick QuizQuick Quiz
Gel electrophoresis separates molecular
products based on:
A. Shape
B. Size
C. Charge
D. Evolutionary similarity
4. ExamplesExamples
Gel Electrophoresis
is used to
visualize…
Genomic DNA
RNA
PCR products
Plasmids
Restriction enzyme
digest products
http://www.steve.gb.com/images/science/agarose.jpg
7. AgaroseAgarose
Alternating sugar units
form linear chains
Cross-linking chains via
hydrogen bonds forms
porous matrix
Heat breaks matrix
apart
Cooling forms a matrix
with an “average” pore
size
http://www.bioscience-beads.com/images
8. Quick QuizQuick Quiz
When traveling through an agarose gel, larger
molecular products will migrate _________
smaller molecular products.
A. Faster than
B. Slower than
C. At the same rate
9. Why Run a Gel?Why Run a Gel?
Molecular weight
markers are DNA
fragments of known
size
Comparison of sample
bands to markers
allows…
Visible confirmation of
desired product
Quantification of sample
DNA
http://www.biomedcentral.com/content/figures/1471-2180-5-63-2.jpg
11. Quick QuizQuick Quiz
As DNA has a net _______ charge, it migrates
towards the gel box’s _________.
A. Positive; cathode
B. Positive; anode
C. Negative; cathode
D. Negative; anode
12. Visualizing DNAVisualizing DNA
Ethidium Bromide
binds to DNA
Fluorescence under
UV light makes
bands visible
http://www.lanl.gov/news/albums/bioscience/AnthraxUVplate.sized.jpg
13. Quick QuizQuick Quiz
The size of the molecular products is
determined by:
A. The intensity of the band
B. The percentage of agarose gel
C. Comparison with a molecular weight “ladder”
D. Being familiar with your gel and “eyeballing” it
14. Gel ElectrophoresisGel Electrophoresis
Prepare agarose gel
Melt, cool and add Ethidium Bromide. Mix thoroughly.
Add running buffer, load samples and marker
Run gel at constant voltage until band separation occurs
Pour into casting tray with comb and allow to solidify
View DNA on UV light box and document results
15. Quick QuizQuick Quiz
Buffer is used instead of water when making
and running gels because:
A. Buffer enhances the transmission of electric
currents in water
B. Buffer is more homogeneous than water
C. Buffer neutralizes the charge on molecular products
prior to electrophoresis
D. Buffers can be customized based upon the
electrophoresis protocol
18. ResourcesResources
Gel Electrophoresis Handout
DNA Science: A First Course in Recombinant DNA
Technology, by David A. Micklos and Greg A. Freyer
http://www.sumanasinc.com/webcontent/anisamples/majors
http://learn.genetics.utah.edu/units/biotech/gel
19. California State Chemistry StandardsCalifornia State Chemistry Standards
Grades 9-12
2. Properties of matter result from the ability of atoms to form
bonds…
6. Solutions are homogenous mixtures of two or more
substances
10b. Students know the bonding characteristics of carbon…
20. California State Biology StandardsCalifornia State Biology Standards
Grades 9-12
5d. Students know the general structure and function of DNA
21. California StateCalifornia State
Investigation and ExperimentationInvestigation and Experimentation
StandardsStandards
Grade 7
a. Select and use appropriate tools and technology to perform tests,
collect data, analyze relationships, and display data
Grades 9-12
c. Identify possible reasons for inconsistent results, such as
sources of error or uncontrolled conditions
d. Formulate explanations by using logic and evidence
k. Recognize the cumulative nature of scientific evidence
l. Analyze situations and solve problems that require combining
and applying concepts from more than one area of science
An electric current is used to propel the DNA through a porous gel matrix. Double-stranded DNA molecules are linear. Length directly relates to size and molecular weight.
An electric current is used to propel the DNA through a porous gel matrix. Double-stranded DNA molecules are linear. Length directly relates to size and molecular weight.
Sugar units = galactose and 3,6-anhydrogalactose (agarobiose units)
1-3 & 1-4 linkages form LH double helices.
Sugar units = galactose and 3,6-anhydrogalactose (agarobiose units)
1-3 & 1-4 linkages form LH double helices.
Other reasons to run a gel: purity determination, isolation of one DNA band from other bands for sequencing purposes
Sugar units = galactose and 3,6-anhydrogalactose (agarobiose units)
1-3 & 1-4 linkages form LH double helices.
Ethidium Bromide is toxic. Consult MSDS prior to use.
Sugar units = galactose and 3,6-anhydrogalactose (agarobiose units)
1-3 & 1-4 linkages form LH double helices.
Sugar units = galactose and 3,6-anhydrogalactose (agarobiose units)
1-3 & 1-4 linkages form LH double helices.