Name___________________________
Date __________ Period____ Group___
Techniques Lab B:
Electrolysis and Electrophoresis
A__________
B__________
C__________
OBSERVATIONS:
1. Label the above illustration of the power supply and gel boxes. Don't forget to label the
positive and negative connections.
2. Draw lines representing electrical leads to show how the gel boxes should be connected
to the power supply.
3. Explain in words how you knew where to connect the electrical leads (question # 2):
_______________________________________________________________________
As we move through the procedure record your observations here.
STEP
2
5
6
GEL BOX
CONTENTS
Empty gel box
(air only inside)
Distilled water
Distilled H2O + NaCl
POTENTIAL
(volts)
120V
120 V
120 V
7
Distilled H2O + NaCl
+ phenol red
120 V
10
Distilled H2O + NaCl
+ phenol red + buffer
-----
11
Distilled H2O + NaCl
+ phenol red + buffer
120 V
OTHER OBSERVATIONS
(color changes, bubbles,
etc.)
Time for
Change
1. Write the equations here:
a) Red Lead:
b) Black Lead:
2. Summarize in your own words the effects of the following on the current:
a) sodium chloride ____________________________________________________
b) phenol red_________________________________________________________
c) buffer ____________________________________________________________
3. When and where were gases produced?
4. What was the source of the gases you observed? What kind of gas was it?
5. What did the color change in phenol red indicate about the pH in the gel box when you
had salt water in the box?
6. After you added buffer, what effect did this have on the initial color of phenol red?
a) Did it have any affect on the color later on?
7. What effect does a buffer have on the pH of a solution (from Chapter 4)?
8. Explain why the following components are a necessary part of the solution which you will
use to electrophoresis DNA:
a) Sodium chloride ____________________________________________________
b) buffer ____________________________________________________________
9. Does the liquid in the gel box become more acidic or basic at the anode? How can you
tell?