The document provides genetics practice problems involving monohybrid and dihybrid crosses. It asks the student to determine genotypes from phenotypes and phenotypes from genotypes for traits like flower color, eye color, hair texture, and seed shape. It also has the student set up and solve Punnett squares to determine the expected percentages of offspring with particular traits from given parental crosses.

1. Science 9 Name: _______________________________
Date: __________________ Blk: _________
Genetics Practice Problems
1. For each genotype, indicate whether it is heterozygous (HE) or homozygous (HO)
AA _____ Bb ______ Cc _______ DD _______
Ee _____ ff ______ Gg _______ hh ________
2. For each of the genotypes below, determine the phenotype.
Purple flowers (P) are dominant to white flowers (p). Brown eyes (B) are dominant to blue eyes (b).
PP _____________________________________ BB ____________________________
Pp _____________________________________ Bb ____________________________
pp _____________________________________ bb ____________________________
3. For each phenotype, list the genotypes.
Curly hair (C) is dominant to straight hair (c). Tall plants (T) are dominant to short plants (t).
___________________________ curly ____________________________ tall
___________________________ curly ____________________________ tall
___________________________ straight ____________________________ short
4. Set up the Punnett square for each of the crosses listed below. The trait being studied is
round seeds (dominant = R) and wrinkled seeds (recessive = r)
Rr x rr What percentage of the
offspring will be round?
_____________________
_____
Rr x Rr What percentage of the
offspring will be round?
_____________________
_____
RR x Rr
What percentage of the
offspring will be round?
_____________________
_____

2. Practice with Crosses. Please show all work!
5. A TT (tall) plant is crossed with a tt (short) plant. What percentage of the offspring will be tall?
6. A Tt plant is crossed with a Tt plant. What percentage of the offspring will be short?
7. In pea plants, purple flowers (P) are dominant to white flowers (p). If two white flowered plants
are crossed, what percentage of their offspring will be white flowered?
8. A white flowered plant is crossed with a plant that is heterozygous for the trait. What
percentage of the offspring will have purple flowers?
9. Two plants, both heterozygous for the gene that controls flower color, are crossed. What
percentage of their offspring will have purple flowers? What percentage will have white flowers?