Transcript Arabinose induction - Olympic High School Home Page

Warm-up
• To which tube(s) did we add bacteria?
• To which tube(s) did we add plasmid?
• What two genes were located on the
plasmid?
• Why are both of these genes important for
our experiment?
Questions about procedure
• Why did we place the bacteria in
hot water (42 degrees Celsius)
for 50 seconds?
Questions about procedure
• What is meant by a “control
plate”?
• What purpose does a control
serve?
Questions about procedure
• What is the purpose of the
ampicilin in the growth media?
Prediction
• On which plates would you expect to find
bacteria most like the original nontransformed E. coli colonies that you
started with?
– Explain your prediction.
Prediction
• If there are any genetically transformed
bacterial cells, on which plate(s) would
they most likely be located?
– Explain your prediction
Data Table
• You will need to create a data table in your
lab notebook. This table should include
the following information for all four plates:
– Number of Colonies on Day One
– Number of Colonies on Day Two
– Number of Glowing Colonies on Day Two
Add arabinose to the
environment of the bacteria in a
controlled manner
Bacteria with the gene for the green fluorescent protein
will start making the protein only in the presence of
arabinose. We say that the gene is “turned on” with
arabinose and “turned off” in the absence of arabinose.
arabinose
solution 3%
(0.3 g/10 ml)
water
Pre-cut
filter
paper
arabinose
solution 3%
(0.3 g/10 ml)
Pre-cut
filter
paper
water
Pre-cut
filter
paper
Pre-cut
filter
paper
arabinose
solution 3%
(0.3 g/10 ml)
water
Filter paper
soaked in
arabinose
Filter paper
soaked in
water
NOTE: Use different shapes for easy identification of which
paper is soaked in arabinose and which paper is the control
Experimental setup
Filter paper
soaked in
arabinose
Filter paper
soaked in
water
LB agar, + ampicillin
+ plasmid
no plasmid
LB agar, no ampicillin
+ plasmid
no plasmid
Conclusion
• Cite evidence from the bacterial
transformation experiment to support
the following statements:
Statement 1
•
•
The antibiotic ampicillin kills normal
E. coli bacteria.
Write it down and then cite evidence
from the bacterial transformation
experiment to support it.
Statement 2
•
•
Only a small percentage of bacteria
exposed to plasmid DNA take in the
DNA during the heat shock procedure.
Write it down and then cite evidence
from the bacterial transformation
experiment to support it.
Statement 3
•
•
An organism’s DNA influences which
proteins it makes.
Write it down and then cite evidence
from the bacterial transformation
experiment to support it.
Next day
Draw this in your lab book and
label it as “Conditions”
Conditions:
+ pGlo,+AMP
+pGlo, -AMP
Draw what you see on
each plate. Where there
are colonies, indicate
which are green and
which are not.
Be sure to record data in
your data table as well.
-pGlo, +AMP
-pGlo, -AMP
Experimental setup
Filter paper
soaked in
arabinose
Filter paper
soaked in
water
LB agar, + ampicillin
+ plasmid
no plasmid
LB agar, no ampicillin
+ plasmid
no plasmid
EXPECTED RESULTS
Filter paper
soaked in
arabinose
Filter paper
soaked in
water
LB agar, + ampicillin
+ plasmid
no plasmid
LB agar, no ampicillin
+ plasmid
no plasmid
Statement 4
•
•
An organism’s environment
influences which proteins it makes.
Write it down and then cite evidence
from the bacterial transformation
experiment to support it.
Statement 5
•
•
One way organisms respond to their
environment is by changing whether a
protein is made or not. In other
words, they respond to their
environment sometimes by turning
genes “on” or turning genes “off.”
Write it down and then cite evidence
from the bacterial transformation
experiment to support it.
Discussion
• Include how reliable you feel the results
are and any errors that could have
changed them. Suggest improvements to
the lab to increase the validity of the
results
Final Assessment
•
•
•
•
•
•
In your own words, explain the
relationship between these terms:
DNA
Protein
Environment
Gene
Trait