1. Practice Problems

2. Genotype vs. Phenotype Yellow (Y) vs. Green (y) Pea Plants
Genotype Phenotype
Homozygous dominant
Heterozygous
Homozygous recessive

3. Genotype vs. Phenotype Purple (P) vs White (p) Flowered Pea Plants
Genotype Phenotype
Homozygous dominant
Heterozygous
Homozygous recessive

4. Genotype vs. Phenotype Round (R) vs Wrinkled (r) Pea Plant Seed Shape
Genotype Phenotype
Homozygous dominant
Heterozygous
Homozygous recessive

5. Genotype vs. Phenotype Smooth (S) vs Wrinkled (s) Pea Plant Pod Shape
Genotype Phenotype
Homozygous dominant
Heterozygous
Homozygous recessive

6. Probability of Genotype for a Heterozygous Cross
Ratio % TT Tt tt
T t T t

7. Probability of Phenotype for a Heterozygous Cross
Ratio % TT Tt
Tall tt
Short
T t T t

8. Probability of Genotype & Phenotype for a Homozygous Cross
Ratio % TT Tt
Tall tt
Short
T T T

9. Spongebob & Friends
Scientists at Bikini Bottoms have been investigating the genetic makeup of the organisms in this community.
Use the following information to test your knowledge of genetics.

10. Spongebob Yellow body color is dominant to blue
What is Spongebob’s phenotype?
Yellow
What is Spongebob’s possible genotype?
YY or Yy

11. Patrick Tall head is dominant to short head.
What is Patrick’s phenotype?
Tall
What is Patrick’s possible genotype?
TT or Tt

12. Spongebob
Spongebob Squarepants recently met SpongeSusie Roundpants at a dance.
Spongebob is heterozygous for his squareshape, but Susie is round.
What are the possible genotypes if they had children?
Draw a Punnett Square

13. Spongebob What are the chances of a child with a square shape?
___ out of ___
___%
What are the chances of a child with a round shape?

14. Patrick Patrick recently met Patti at a dance.
Both of them are heterozygous for their pink skin color which is dominant over yellow.
What are the possible genotypes if they had children?
Draw a Punnett Square

15. Patrick What are the chances of a child with pink skin? ___ out of ___
___%
What are the chances of a child with yellow skin?

16. Squidward
Squidward’s family has light blue skin, which is the dominant trait for body color.
His family brags that they are a “purebred” line.
He recently married a nice girl with light green skin, which is a recessive trait.
What are the possible genotypes if they had children?
Draw a Punnett Square

17. Squidward What are the chances of a child with blue skin?
___ out of ___
___%
What are the chances of a child with green skin?

18. Mr Krabbs
Mr Krabbs and his wife recently had a Lil’ Krabby, but it has not been a happy occasion.
Mrs. Krabbs has been upset since she first saw her baby who had short eyeballs.
She claims that the hospital goofed and mixed up her baby with someone else’s baby.
Mr. Krabbs is homozygous for his tall eyeballs, while Mrs. Krabbs is heterozygous.
Draw a Punnett Square to figure out if the hospital made a mistake.