WHAT ARE YEAST?
• Eukaryotic microorganisms
• Types of fungi
• Unicellular organisms
• Molds
• Used in winemaking, baking, and brewing
• Fermentation is the process in which the yeast
converts carbohydrates to carbon dioxide and
alcohols
SO WHAT? WHY ARE WE TALKING ABOUT
YEAST?
• Yeasts are model organisms
• Size
• Generation time
• Accessibility
• Ease of care and manipulation
• We are going to use them next week in an experiment
to study populations
• You will work with your group to sample a population
of yeast over 8 days
TODAY
• Learn how to calculate population sizes from a sample
collected
• Recall the sampling lab from last week
• Your practice calculations sheet will be due on BLOCK
• Practice these calculations (Check for Understanding
this FRIDAY)
SCIENTIFIC NOTATION…
…A quick way to write really, really BIG (or really, really,
small) numbers
• Using powers of 10, you can create short versions of long
numbers
• Proper Scientific Notation
• A number must be between 1 and 10
• Must be multiplied by a power of ten
• Ex: 45 X 108 is NOT proper scientific notation. Why not?
EXAMPLES OF SCIENTIFIC NOTATION
• 76,000,000 can be rewritten as…
• 7.6 X 107
• 0.000000089 can be rewritten as…
• 8.9 X 10-8
YOUR TURN
Use Scientific Notation to rewrite the following numbers:
1. 347,000
2. 902,000,000
3. 0.0000614
Answers:
1. 3.47 X 105
2. 9.02 X 108
3. 6.14 X 10-5
SWITCH THESE BACK TO THEIR LONG FORMS
1. 6.08 X 106
2. 1.23 X 105
3. 8.25 X 10-2
Answers
1. 6,080,000
2. 123,000
3. 0.0825
HEMOCYTOMETER SLIDE
WE WILL BE USING THIS SLIDE IN THE LAB TO SAMPLE
OUR YEAST POPULATIONS
HEMOCYTOMETER SLIDE