Transcript pGLO
Gel Electrophoresis Lab
Analysis of Precut Lambda DNA
Restriction Enzymes
Our lambda virus DNA
samples have been precut
with three different
restriction enzymes.
L – lambda DNA
P – PstI lambda digest
E – EcoRI lambda digest
H – HindIII lambda digest
Running the Gel
• The phosphate groups in
the sugar-phosphate
backbone of DNA are
negatively-charged.
• Molecules move through
the gel at different rates,
determined largely by
their size and charge.
Shorter molecules move
through the gel faster
than longer molecules.
Reasons for Each Step
Loading Dye
Two sizes of blue molecules, small
and large, help visualize movement
of sample across gel.
Heat DNA Samples
Denatures double stranded DNA to
produce single strands that more easily
move through gel.
Reasons for Each Step
Tap Tubes on Table Top
moves sample to bottom of tube for collection
Run the Gel in Chamber
electrical field pulls negatively charged DNA through
the gel, with distance moved proportional to size
Stain Overnight
stain attaches to DNA within gel, making bands of
DNA visible
Lab Tips
• Follow the “How to Use a Micropipet” instructions at
your station.
– When finished, eject the tip into the disposal at your station.
• Carefully handle the DNA samples!
• Be sure your gel is well-side up and fully
submerged in the buffer solution.
• Hold the micropipet just over the
well. Be careful not to puncture
the bottom of the well with the
micropipet!
• Use tape to label which gel is yours (top or bottom).