1. Yeast and Fermentation
Biotechnology

2. Essential Questions:
What are the key components in Yeast Growth Medium?
How does yeast obtain energy through the processes of cellular respiration and fermentation?

3. Eukaryotic Cells
Found in model organisms mice, rats, fruit flies, arabidopsis, and yeast
What distinguishes a eukaryotic cell from a prokaryotic cell?

4. Example of Eukaryotic Cell
Saccharomyces cerevisiae –yeast
A fungus
Found in sugar rich material (e.g. skins of fruits and berries and exudates from plants (such as plant saps or cacti).

5. Significance to Biotechnology
Serves as eukaryotic model organism like E. coli for prokaryotes
Important to Pharmaceutical Industry
Ex. Important source of antibiotics and drugs to lower cholesterol
Important to production of biofuels
Genetic engineering Yeast to become more alcohol tolerant
Ethanol used in biofuel production
Important to the Food Industry
Baking of bread
Production of beer and wine

6. Culture Medium for Growing Yeast
Like E. coli, can be grown in either a liquid (i.e. broth) or on a solid medium (i.e. agar)
Typical broth used for yeast is YPD medium
This broth contains
Yeast extract (Y)-vitamins and trace elements
Peptone (P) – amino acids
Dextrose (glucose-D) - carbon source

7. Why does yeast need a carbon source?
To make energy in the form of ATP needed for cell division and synthesis of key macromolecules-protein, carbohydrates, lipids, and DNA
Yeast can make ATP in one of two ways
Presence of oxygen by cellular respiration
Absence of oxygen by fermentation

8. Cellular Respiration
Process in which glucose is broken down to CO2 and water in the presence of O2
Most of the pathway occurs in the mitochondria
Makes 34 ATP
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9. Fermentation
Process in which glucose is broken down to ethyl alcohol and CO2 in the absence of oxygen
Occurs in the cytoplasm
Makes less energy – only 2 ATP

10. PROPERTY OF PIMA COUNTY JTED, 2010
Think-Pair-Share
Which pathway would humans use if they are O2 deprived?
3. Think-pair-share
teacher presents a question
teacher gives wait time for student to form answer
teacher instructs students to share their answer with a partner
teacher calls on non-volunteers to share with the class
PROPERTY OF PIMA COUNTY JTED, 2010
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11. Example of How Yeast and Fermentation Is used in making root Beer
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12. Ingredients of Root Beer
Sugar
Yeast
Sassafras root
Burdoch root
Sarsaparilla root
Spikenard root
water

13. Sugar
Sweetens the root beer
Provides a carbon source for the yeast

14. Yeast
Provide the biochemical process fermentation to generate CO2 for carbonation

15. Flavoring Comes from extracts of
Sassafras root
Burdock root
Sarsaparilla root
Spikenard root
Instead of grinding up each root and extracting the flavor, we will use a root beer extract