miniPCR bio
TM
Dye Electrophoresis Lab: Molecular Rainbow - Student's Guide
Version: 1.0 - Release: April 2022 - © 2022 by miniPCR bio™
Student's Guide
P./11
Interpreting gel results
You can get a lot of information from gel electrophoresis results! There are three pieces of
information that we will focus on today: charge, composition, and size.
- - - - - - Negative - - - - - -
+ + + + + + Positive + + + + + +
Green
Green
Blue
Blue
Purple
Purple
Yellow
Red
Lane
1
Lane
2
Lane
3
Lane
4
Lane
5
Lane
6
How big were the molecules in the sample
compared to each other?
- Smaller molecules can move through the gel
easily and will travel farther from the wells than
larger molecules with the same charge. In Lane
5, the purple band moved farther from the well
than the blue band. If we assume the purple and
blue molecules have the same net charge, we
can infer that the purple molecules are smaller
than the blue molecules.
- Molecules that are the same size and charge
will travel the same distance. The purple band
in Lane 5 and the red band in Lane 6 traveled
the same distance from the well. If we assume
the purple and red molecules have the same
net charge, we can infer that the purple and red
molecules are about the same size.
3
What is the charge of the molecules that
were in the sample?
- Charged molecules will be attracted to
the opposite charge.
- The attractive force will cause positive
molecules to move towards the negative
electrode. The green band in Lane 1 is
made of positively charged molecules.
- Negative molecules will move towards
the positive electrode. The blue band in
Lane 2 is made of negatively charged
molecules.
1
What is the composition of the
molecules that were in the sample?
Put another way, how many types of
molecules were in the sample?
- If there is only one band in a lane it
usually means that there is just one
type of molecule in that sample.
Lane 3 has only one green band,
meaning only one type of molecule
was placed in the well.
- If there is more than one band in
the lane, it means there is more than
one type of molecule in that sample.
Lane 4 has two bands, a yellow
band and a purple band, meaning a
mixture of two molecules was placed
in the well.
2
