Download What is DCPIP

Happy Early Thanksgiving!
Updates:
• Quiz 10 grades are updated, new
average: 76%
• Last quiz average: 78%
• Tools of the Light Trade assignment
counts as one quiz grade! Scores are
up
• Light Tools Findings grades will be
posted by the end of the night
• I’m still missing just a few GD peer
evals…
Photosynthesis and
Electron Transport
System
Let’s think…
• Electron transport…
• REDOX reactions?
• OIL RIG!
Why we’re here:
• Solve a question about the ‘invisible world’
through experimental design and execution
• Design the experiment given tools you have
and processes you’re familiar with
• Derive the purpose and implementation of
‘controls’ for your experiment
Where we’re going
• Given: DCPIP takes electrons from Pq
In groups of two…
• What is DCPIP (Dichlorophenolindophenol)?
• Does it share any characteristics with
other molecules we’ve seen this
semester? What?
• What does it do?
• How can you tell what it’s doing/what it’s
done?
Reduction of DCPIP:
Claims:
• DCPIP steals electrons
– What effect do you predict this will have
on photosynthesis/oxidation of H2O by
Photosystem II?
• An unknown herbicide blocks electron
transport like a brick wall
– What effects do you predict?
Verify these claims!
• How? Use the leaf disk assay we’ve
been working with!
• What conditions?
• Key Question of the day: Where does
the herbicide act? Before or after
DCPIP?
Will Photosynthesis happen
in DCPIP?
• How would you know?
• Add 4ml DCPIP + 20mL buffer
• ALSO, confirm an herbicide (Diuron) is
a photosynthicide
• Add 0.75mL + 20mL buffer*
• Give your disks time to let the herbicide
soak in
• *Ignore the change in volume adding
these produce
Evaluations
• What did you learn? (Can be done
individually while experiments
progress)
• What did you think of the semester
(requires lab instructor to be finished &
gone; but you can come back)
Question of the day/week…
X
X
WHERE does the herbicide work?
Oh the thinks you can think!
X
X
DCPIP taking
taking -e
e- will
will
• DCPIP
do what
what to
to O
O2 prod?
prod?
do
2
How will
will -e
e- taking
taking
• How
affect DCPIP?
DCPIP?
affect
• How can you tell if
drug acts here?
• Or here?
Oh the thinks you can think!
• Two hypotheses?
• What would your experiment look
like?
• What would it TELL you if the
DCPIP…
–Stays blue
–Turns clear
“Throw her into the pond!”
• What tubes will you need?
• Work it out now
• Use the diagram