Practice Problems

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

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

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

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

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

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

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

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.

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

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

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

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?

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

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

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

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

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.