Download Punnett Square Practice Problems

Punnett Square Practice Problems
Name:
Date:
Period:
Directions: For the following questions, create a Punnett square. Be sure to show the
genotypes, phenotypes, and percentages for each cross.
1. In guinea pigs, black fur in dominant over white fur. Cross two heterozygous black
guinea pigs. (4 pts)
2. In peas, side flowers are dominant over end flowers. Cross a homozygous recessive plant
with a heterozygous plant. (4 pts)
3. Black fur in rabbits is dominant over brown fur. Cross a homozygous black rabbit with a
brown rabbit. (4 pts)
4. In pea plants, colored seeds coats are dominant to white seed coats. A heterozygous plant
is crossed with a white seed coat plant. What is the chance of homozygous dominant
offspring? (5 pts)
5. Mendel first made sure that he had purebred dominant green pod plants and then he
crossed them with yellow pod plants. What is the probability that the offspring are
green? (5 pts)
6. Second, Mendel used the offspring from the first cross and allowed them to self pollinate.
What is the probability that the resulting offspring are yellow? (5 pts)
7. Fur color in animals is frequently controlled by more than one gene. However, brown
fur in rabbits is dominant over white fur. A white female gives birth to all white rabbits,
even though the father had brown fur. Show how this is possible. (5 pts)