1. Do now activity
In pea plants, yellow seed color (Y) is dominant over green seed color (y). Complete the cross between a plant that is heterozygous for yellow seeds and a plant that is homozygous recessive.

2. Section 4-3: Punnet Squares
Essential Question:
How can a punnet square be used to predict the probability of offspring genotypes and phenotypes based on the parents genotype?
Learning Target
Use a punnett square to predict the probability of offspring genotypes and phenotypes based on the parents genotype.
Section 4-3: Punnet Squares

3. announcements Biology Tutoring schedule W&F @ 7:00AM Section 4 Test
Scheduled for Friday: 11/17/17
Section 4 Lab
TBA
Class website will be updated today

4. announcements Available Extra Credit: 3 Tissue Boxes = 1 class pass
Color Printer Paper = 1 class pass Plastic Pencil Box = 1 class pass

5. Don’t forget to chunk your notes!

6. Probability: the likelihood that an event will occur.
overview
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Probability: the likelihood that an event will occur.

7. When you flip a coin, what is the probability that you will get Tails?
overview
When you flip a coin, what is the probability that you will get Tails?
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8. The probability of a particular event occurring from a coin toss is
overview
Example: Coin Toss
The probability of a particular event occurring from a coin toss is
½ or 50%
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9. overview Example: Coin Toss Possible events:
Heads = ½ or 50% probability
Tails = ½ or 50% probability
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10. Don’t forget to chunk your notes!

11. Traits
Based on genetic information, we can use a Punnet Square to determine the probable traits of our children.
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12. Traits are controlled by genes
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13. Don’t forget to chunk your notes!

14. Punnet squares Steps Define your letters Set up your cross-breed
Draw your Punnet Square
Law of Segregation
Solve the Punnet Square
Calculate probabilities
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15. Mono-Hybrids: crosses between parents for a ______ trait.
Punnet squares
Mono-Hybrids: crosses between parents for a ______ trait.
Examples:
Dimples, Cleft chin, Freckles, Widow peak
single
single

16. Punnet squares
Di-Hybrids: crosses between parents for two ________ traits.
Examples:
Freckles & Cleft chin
Dimples & Widow peak
different
different

17. Punnet squares Di-Hybrid = combining 2 different traits
Ex. Freckles x Dimples

18. Practice question
In humans, tongue rolling is dominant over non-tongue rolling. Use a Punnett square to predict the probability of having a non- tongue rolling baby for a cross between a person heterozygous for tongue rolling and a person who is homozygous for non-tongue rolling.
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19. Practice question Heterozygous for tongue rolling And T t
homozygous for non-tongue rolling.
T t t
T t
t t
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T t
t t

20. Don’t forget to chunk your notes!

21. Alleles separate during ______ formation
Law of segregation
Alleles separate during ______ formation
gamete
gamete

22. Law of segregation Dominant Allele The trait is always expressed
Shown by a capital letter
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23. Law of segregation Recessive Allele
Trait is expressed when a dominant allele is not there
Shown by lowercase letter
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24. Gametes Segregation Parent Generation D d D d
Baby
Generation DD Dd Dd dd
Results: DD = Dimples Dd = Dimples dd = no dimples
75% Dimples, 25% No Dimples

25. Don’t forget to chunk your notes!

26. Practice Question!
In humans, straight thumb (S) is dominant over hitch-hikers thumb ( s ). Use a Punnett square to predict the probability of having a baby with hitch-hiker thumb for two people heterozygous for straight thumb.
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27. Practice Question! And S s S s S S S s S s s s
Heterozygous for straight thumb
And
Heterozygous for straight thumb.
S s S s
S S
S s
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S s
s s

28. Practice Question! T t T t T t T t
The allele for tall plant (T) is dominant over the allele for short plant (t). A homozygous tall plant is bred with a homozygous short plant.
T t
T t
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T t
T t

29. How is it possible to have 100% TALL
Practice Question!
How is it possible to have
100% TALL
pea plant offspring when the genes were
50% Tall (mom) and 50% Short (dad)?
T t
T t
T t
T t

30. Do now activity
Dimples (D) is dominant over no dimples (d). A woman heterozygous for dimples has a child with a man heterozygous for dimples. *Use a punnet square to determine the probability of the couple having a child without dimples.