Bacterial Transformation:
Experimental Design Pre-Lab Activity
Student Instructions
1. Get a packet of Procedure I cards (16 total, white background) and a packet of
Tool cards (yellow background).
2. In the Procedure cards, find the Starting Materials (3) and the End Results (2).
3. Lay the other cards out on the table and use them as moveable pieces of a flow
chart, to organize your experimental procedure. You should end up with an
outline of your procedure in picture form, showing each necessary step and tool to
go from the starting materials to the end results.
Suggested methods:
 You may want to ignore the Tool Cards initially, and first lay out a
procedure that makes sense to you. Then, you could go back and select
the appropriate tools for each step.
 Or, you may want to choose a tool for each step as you go along.
Notes: There are extra copies of some cards. You may need them, or you may
not. Also, some tools may not be necessary for your procedure. Use your
knowledge of biotechnology techniques to choose the tools you need.
4. When you think you have a good procedure outlined, check with your teacher.
He/she will pick a random student in your group to explain your thinking, so be
sure that all group members are prepared to do that!
5. Get a packet of Procedure II cards. Use them to organize your thoughts about
how to accomplish the following:
a. Select for only the recombinant bacteria in your transformation (because,
as the cards show, not every bacterium in the tube gets transformed – this
is by chance, not by laboratory error).
b. Make the recombinant bacteria glow.
c. Demonstrate that it’s the presence of the recombinant plasmid that confers
the abilities to resist ampicillin and to glow. (This is the control part of
your experiment.)
All images designed by Christine Rodriguez and Amy Dickson
Summer 2008 Workshop in Biology and Multimedia for High School
Teachers
Harvard University Life Sciences – HHMI Outreach Program
6. When you are finished, get a copy of the lab procedure. In your group, read aloud
each step of the procedure and use it to:
 Check against your flow chart. If there is any discrepancy, discuss until
it’s resolved.
 Determine precise amounts, timings, and temperatures for the steps in
your procedure.
7. Check your work with the teacher, then write out your procedure in your lab
notebook.
8. In your lab notebook, draw a data table with spaces for expected and observed
results. Fill in the expected results. Be sure that every member of your group can
explain your experimental setup and your expectations – you may be called on to
explain them to the class at the start of lab tomorrow!
All images designed by Christine Rodriguez and Amy Dickson
Summer 2008 Workshop in Biology and Multimedia for High School
Teachers
Harvard University Life Sciences – HHMI Outreach Program
Teacher Guide
Overview and Rationale:
This pre-lab activity is designed to be used with an AP Biology class in preparation for
Lab 6: Bacterial Transformation. After teaching AP Biology for several years, I have
found that the procedure for this lab is complex enough, and involves so many invisible
molecular processes, that students lose sight of what they are doing and why. This prelab activity is part of a course-wide change in my AP Biology curriculum that puts a
stronger emphasis on students designing their own lab procedures. Rather than handing
students the procedure and having them follow it, they are given the overall question or
goal of the experiment, and asked to design a procedure on their own. The specific lab
procedure, which can be found in the AP Biology Lab Manual for Students or with the kit
used for this lab, is then used as a reference for students to check their experimental
design and to get guidance on specific amounts and timings needed. The idea is that
while students are guided to come up with the same procedure that is in the manual, they
will understand it better if they’ve designed it themselves. Moreover, if some students
come up with a different procedure, depending on the teacher’s comfort level they could
try it despite its probable eventual failure – the idea being that students learn more from
self-directed failures than from rote successes.
Lesson Components:



Introductory Powerpoint Presentation – this provides an introduction to the lab for
students, before they are asked to design a procedure. It reviews some basic terms
necessary for understanding the lab, and outlines the starting materials and end goals
of the experiment. This presentation intentionally does not explain everything
necessary for understanding the procedure – the goal being that students figure some
things out on their own.
Procedure Cards – These are in the form of a powerpoint file, but are not meant to be
shown as a presentation. Rather, the teacher should print the file with 6 slides per
page, and then cut out the slides to make small cards. If possible, print on a color
printer and them laminate the cards so that they can be reused.
The first 16 cards should be bundles as the Procedure I cards, and the remaining cards
as the Procedure II cards.
Tool Cards – These are also in the form of a powerpoint file, but similarly should be
printed and cut out for student use. The tool cards have a yellow background to
distinguish them from the Procedure Cards.
Lesson Procedure:
The student instructions outline the procedure for this pre-lab activity. It is designed to
be carried out in one class period, the day before the lab. The introductory presentation
should take about 15 minutes, and the activity should take about 30 minutes. Students
should work in groups of 2-4. As students work on their procedures, the teacher should
All images designed by Christine Rodriguez and Amy Dickson
Summer 2008 Workshop in Biology and Multimedia for High School
Teachers
Harvard University Life Sciences – HHMI Outreach Program
circulate amongst the groups, asking questions but trying not to give answers. After each
group finishes with the Procedure I cards, the teacher should have students explain their
procedure before moving on. Important things to point out to students during this
discussion include:
 The pGLO plasmid has already been engineered, so the first steps of their
procedure won’t be carried out in this lab.
 Notice that in the end result of the recombinant bacteria, not all cells have been
transformed. This is an expected result due to random chance, and not to error.
However, it means that the students must determine how to select for only the
recombinant bacteria in Procedure II.
Variations:

The Procedure Cards can be used as a presentation, rather than printed out for student
use, if the teacher wants to walk students through the procedure rather than having
them design it themselves. Or, Procedure I could be presented and Procedure II left
to students.

Students could work together to create a skit of the procedure, with different people
acting as the plasmid, the GFP gene, etc. The Procedure and Tool Cards could be
printed out one per page and used as nametags for the various roles in the skit.

If Procedure I turns out to be too confusing (it has a lot of movable parts!), it could be
divided into two parts, so that the entire thing becomes three parts:
Procedure I: Create the recombinant plasmid.
Procedure II: Transform the cells to create recombinant bacteria.
Procedure III: Select for only the recombinant bacteria, make them glow, and
demonstrate that glowing and antibiotic resistance is due to the plasmid.
All images designed by Christine Rodriguez and Amy Dickson
Summer 2008 Workshop in Biology and Multimedia for High School
Teachers
Harvard University Life Sciences – HHMI Outreach Program