1. Saccharomyces cerevisiae is Brewer’s Yeast
This is the same yeast that is used to leaven bread and ferment alcohol in beer and wine

2. Saccharomyces cerevisiae is a Model Organism
Model organisms are used to study biological processes, with the hopes of extrapolating results to humans. They are less expensive to maintain, reproduce faster, and raise fewer ethical questions.

3. Yeast are Eukaryotic
Yeast is a fungus. This makes it more closely related to humans than to bacteria, which are prokaryotic.

4. But…yeast?!
Yeast, unlike humans, is unicellular. But, like human cells, yeast:
Has linear chromosomes
Must respirate
Must consume food
Must sense the environment surrounding its cells
Must arrest its growth in response to internal and environmental cues

5. Yeast Can Grow on Liquid or Solid Media
Yeast growth medium (YPD) includes proteins, yeast extract, and glucose. YPD solid media also includes agar.

6. Yeast Reproduce by Budding
Look for budding today
Yeast reproduce asexually by budding, but can reproduce sexually if the opportunity arises.

7. Today’s Experiment Methylene Blue Viability Assay
Our way to testing viability in your projects

8. Methylene Blue Viability Assay
Unlike Trypan Blue, all cells take up Methylene Blue
However, living cells reduce Methylene Blue making it colorless
How? Living cells undergoing glycolysis produce NADH, which reduces Methylene Blue
Oxidized
Dead
Reduced
Alive
NADH
Methylene
Blue
Dead Cell
Living Cell
braukaiser.com