Download Counting Peas with Gregor Mendel

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Counting Peas with Gregor Mendel
The two peas in the bag labeled P1 (Parents) are like peas grown by Mendel from many generations of pea
plants that were self-pollinated. Each of the two peas comes from a plant that only carries information for the
specific traits that you see.
a. What are the colors of the peas? ____________________________________
b. If you took pollen from the plant that produced one of the colors of peas and used it to pollinate the
flowers from the plant that produced the other color, predict what colors color(s) of the peas would be in
the next (first) generation?
Color One: Yellow
# Peas
Color Two: Green
# Peas
Parent Generation
First Generation
Prediction
c. Now show your answers as a ratio (# of Color One: # of Color Two) Example~ 1:0, 1:1, 2:1, 3:1, etc.
Parent Ratio
1:1
F1 Ratio
Prediction
d. Why do you think this will happen? Explain your prediction in complete sentences…
e. Look at the resulting peas from the F1 Generation (first generation of offspring). What were the actual
results? Also give your answer as a ratio.
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F1 Actual Ratio
f. If the results were different that what you expected, why do you think they turned out the way they did?
The next part of Mendel’s famous experiment was to take pollen from one of the F1 plants and use it to pollinate
flowers from the same plant.
g. What do you think the color(s) of the peas will be in the next generation (F2)? Also give your answer as a
ratio.
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_______________________________________________________________________
Parent Ratio
F1 Ratio
F2 Ratio Prediction
h. Why do you think this will happen?
i.
Look at the resulting peas in the F2 Generation (second generation of offspring). Write the result as a
ratio.
F2 Actual Ratio
j. If the results are different than you predicted, why do you think they turned out that way?
Mendel was the first scientist to be successful at figuring out the basic way that many traits are inherited,
although brilliant scientists before him had tried to do so and failed. He was successful for many reasons,
including:
-He was very careful in planning his experiments
-He started with pure plants
-He created at least three generations of plants
Now you are going to have the change to figure out what those brilliant scientists before Mendel were unable
to! If Mendel had been alive today he would have won the Nobel prize for figuring this out. See if you are
worthy of a Nobel!
a. Mendel called the genetic information in plants “factors” today we call them genes. Review the results
from the F1 and F2 Generations of peas. Remember that other scientists looked only at two generations and
not three or more generations of plants (P1, F1, F2).
Color One:
# Peas
Color Two:
# Peas
Parent Generation
First Generation
Second Generation
b. At least how many forms of a gene must each pea plant have for color in order for the parental plants to
produce the resulting peas in the F1 plants? Justify your answer.
c. How many forms of a gene must the F1 plants have passed on to the F2 plants to produce the results we
saw? Justify your answer.
d. Explain how the color green seemed to disappear and reappear.