Fermentation and respiration lab

Outline of the day

1. Turn in your lab reports at the front– More than 10 minutes late = bad

2. Any questions on last week’s lab?

3. Quiz

4. Introduction to the lab

5. Lab!

6. Check out• 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 metabolismin yeast

Metabolism – the minute summary

• Glycolysis– Glucose -> Pyruvate– Produces 2 ATP

Glucose -> -> Pyruvate -> -> NADH & FADH2 -> ->ATP

• Krebs cycle– Big cycle with many reactions– Produces CO2

• Electron transport chain– Uses NADH, FADH2 to produce

ATP– Consumes O2, produces H2O

Missing image:Image showing mitochondria

that can help illustratethe 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 experimentalpoint

• Normal reaction:

• Our experiment:– We’re substituting DPIP for FAD

Succinate Fumarate

FAD FADH2

Succinate Fumarate

DPIP(blue color)

DPIPH2(colorless)

Color change will indicate the reaction’s progress

• 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

Succinate Fumarate

DPIP(blue color)

DPIPH2(colorless)

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

(Note: This picture is of a different setup than we will use)

KOH

Photo of Manduca sexta by Marc Perkins

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 Attribution-NonCommercial-ShareAlike 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/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).

Slides in this presentation based on those created by Marc C. Perkins. http://faculty.orangecoastcollege.edu/mperkins

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)