Punnett Square Practice

Part A: Vocabulary

• Alleles: Different forms of genes for a single trait.
• Dominant: Gene that is always expressed.
• Heterozygous: Genotypes made of two different alleles.
• Homozygous: Genotypes made of the same alleles.
• Recessive: Gene that is expressed only in the homozygous state.

Examples:

• Homozygous dominant: KK, TT, AA
• Homozygous recessive: mm, uu, ee, qq, ww
• Genotypes in which dominant gene must show: EE, Dd, AA, Jj
• Genotypes in which recessive gene must show: aa

Part B: Punnett Squares

Correct Punnett Squares:

Based on the provided examples, the student is instructed to identify correct Punnett squares. Without the visual representation of the Punnett squares, it is impossible to determine which ones are correct. However, a correct Punnett square should follow these rules:

• The alleles of one parent are listed across the top.
• The alleles of the other parent are listed down the side.
• Each box is filled in with the combination of the alleles from its corresponding row and column.

Punnett Square Letter Meaning:

• Letters on the outside: Represent the genotypes of the parents.
• Letters on the inside: Represent the possible genotypes, and thus phenotypes, of the offspring.

Corn Plant Crosses:

• N: Represents the dominant allele for normal height.
• n: Represents the recessive allele for short height.

The student is instructed to complete four Punnett squares for different crosses, but the specific crosses aren't noted. The student is also told to:

• Circle all homozygous dominant offspring.
• Put an X through all heterozygous offspring.
• Leave all homozygous recessive offspring unshaded.