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  Investigate What are some
characteristics of yeast?
  Yeast are tiny organisms. Each is a single cell. In a warm place
with sugar and water, yeast grow quickly. Bakers put yeast in
bread dough to help the bread to rise.
  Materials What to Do
Shake spoonful
of yeast on the
watermelon slice.
  watermelon slice
  yeast
 
spoon 
  
   
  plastic bag
Put the watermelon
slice in the bag. Seal
it and set it in a warm
place. Use a hand
lens to observe the
yeast.
After 1 hour, observe
the yeast. Describe
any changes.
  hand lens
  microscope and
  microscope slide
  The yeast you
observed are
classified as
fungi, based on
their properties
   
Observe the yeast 2 more times.
Describe any changes.
 
 
Time
Appearance of Yeast on
Watermelon Slice
 
After 1 hour
  
 
After 2 hours
  
 
After 3 hours
  
Observe a tiny amount of the
yeast with a microscope. Notice
that the cells are similar to each
other. Draw your observations.
  What tiny organisms
did you see through
the microscope?
 
  Explain Your Results
1. Did the appearance of the yeast change? How?
  2. Yeast are not classified in the plant kingdom or
    the animal kingdom. Why?
  3. Infer Which kind of bread has yeast added to its
    dough, flat bread or loaf bread? Why do you
    think so?
 
  Does yeast need light to
grow? Develop a plan
to answer this or other
questions you may have.