Fermentation and respiration
lab
Outline of the day
1. Turn in your lab reports at the front
–
More than 10 minutes late = bad
Any questions on last week’s lab?
Quiz
Introduction to the lab
Lab!
Check out
2.
3.
4.
5.
6.
•
•
Get a stamp
Make sure I mark you down for attendance
Quiz
• Ends 10 minutes after it’s started
– Ends at: ____
Lab this week!
• Exploring metabolism!
– Fermentation
– Factors that affect enzyme reaction rates
– Heat production by seedlings
– Oxygen consumption by insects
Yeast Fermentation
• Yeast normally do oxidative metabolism
– Just like us (glucose + O2 -> CO2 + H2O)
• When yeast run out of O2
– They do fermentation, producing alcohol and CO2
Missing image:
Image showing the reactions
of anaerobic metabolism
in yeast
Metabolism – the minute summary
Glucose -> -> Pyruvate -> -> NADH & FADH2 -> ->ATP
• Glycolysis
• Electron transport chain
– Glucose -> Pyruvate
– Produces 2 ATP
• Krebs cycle
– Uses NADH, FADH2 to produce
ATP
– Consumes O2, produces H2O
– Big cycle with many reactions
– Produces CO2
Missing image:
Image showing mitochondria
that can help illustrate
the above reactions..
TCA cycle
• We’re going to
look at just one
reaction.
Citric acid cycle ccbyasa by Mike Jones at http://en.wikipedia.org/wiki/Image:TCA.svg
Key experimental
point
• Normal reaction:
Succinate
FAD
Fumarate
FADH2
• Our experiment:
– We’re substituting DPIP for FAD
Succinate
Fumarate
DPIP
DPIPH2
(blue color)
(colorless)
Color change will indicate the
reaction’s progress
Succinate
Fumarate
DPIP
DPIPH2
(blue color)
(colorless)
• As the reaction progresses, our solution will
change from blue to clear
– But this change will be too small to see, so we’ll use
spectrophotometers
Measuring oxygen consumption
• How does it work?
– Insects consume oxygen
• Literally remove it from the atmosphere
– (use it for oxidative respiration)
– Insects product carbon dioxide
• Add it to the atmosphere
– (product of oxidative respiration)
– KOH absorbs carbon dioxide
• So, the volume of gas in the chamber will reduce
by the amount of oxygen consumed
KOH
Photo of Manduca sexta by Marc Perkins
(Note: This picture is of a
different setup than we
will use)
What are mealworms?
• They’re beetle larvae!
Mealworms ccbynd by hans s at http://flickr.com/photos/archeon/15103838/
Adult by attirb by http://www.entomart.be/listetotale.html from http://en.wikipedia.org/wiki/Image:Tenebrio_molitor01.jpg
Key points
• NaF is an enzyme inhibitor
• Remember how pipettes work
• Practice with the spectrophotometer
– Time is critical
• For respiration
– KOH is a chemical that absorbs carbon dioxide
• So the volume of gas in the chamber will reduce as the insect
metabolizes
Before you leave
• Clean up your work area
– Wash glassware and store upside down
• Show me your lab report so I can stamp it
– Need to have all data fields filled in
– Complete at home and then turn in at the beginning of
next lab
• Remember that we’ll have a quiz at the
beginning of the next class
– 6-7 questions on today’s lab
– 3-4 questions on the lab we’ll do next week
Notes for the instructor:
• Add any relevant cleanup instructions to
the final slide (that slide is a generic one
I’m adding to each presentation).
License information
• This work is licensed under the Creative Commons AttributionNonCommercial-ShareAlike 3.0 License. To view a copy of this
license, visit http://creativecommons.org/licenses/by-ncsa/3.0/us/ or send a letter to Creative Commons, 171 Second
Street, Suite 300, San Francisco, California, 94105, USA.
• The slides in this presentation were originally created by Marc
C. Perkins (http://faculty.orangecoastcollege.edu/mperkins).
• You are free to use, modify, and distribute these slides
according to the terms of the Creative Commons license (e.g.,
you must attribute the slides, no commercial uses are allowed,
and future distributions must be licensed under a similar
license).
• Attribution should be given to Marc C. Perkins (and any later
editors), including a link back to Marc’s current website. This
applies both while distributing the slides and during use of the
slides; attribution during use can be satisfied by, for instance,
placing small text on at least one of the slides that has been
shown (see below for an example).
History
• August 2007: Marc Perkins released first
version.
http://faculty.orangecoastcollege.edu/mperkins
(If you modify these slides and redistribute them, add your information to the list)