Monohybrid Cross Practice Problems Worksheet
Name _______________________
Part A: Vocabulary
Match the definitions on the left with the terms on the right.
____ 1. genotypes made of the same alleles A. alleles
____ 2. different forms of genes for a single trait B. dominant
____ 3. gene that is always expressed C. heterozygous
____ 4. gene that is expressed only in the homozygous state D. homozygous
____ 5. genotypes made of two different alleles E. recessive
Below each of the following words are choices. Circle the choices that are examples of each of those words.
6. Dominant allele: D e k L N n R S
7. Recessive allele: M n d F G r k P
8. Homozygous dominant : AA Gg KK mm uu Rr TT
9. Homozygous recessive: ee Ff HH Oo qq Uu ww
Part B: Punnett Squares
12. Examine the following Punnett squares and circle those that are correct.
13. What do the letters on the outside of the Punnett square stand for? ______________________
14. What do the letters on the inside of the Punnett square stand for? ________________________
FOR ALL PROBLEMS, CREATE A PUNNET SQUARE AND GIVE THE PHENOTYPE AND GENOTYPE RATIO
15. Yellow pea pods (Y) are dominant over green pods (y). A heterozygote is crossed with a homozygous dominant
plant.
