1. Punnett Square Vocabulary
Term
Synonyms
Definition
Example
Allele
A letter that represents a genetic trait
B = brown eye color
Parents
P generation
The parents of a cross, the ones contributing egg & sperm (found on the outside of the Punnett square)
Offspring
Children
Kids
F1 generation
(F2 generation)
The potential children produced in a cross (found in the inside of the Punnett square)
Dominant
“Big”
Requires only one allele for the trait to show
BB or Bb has brown eyes
Recessive
“Little”
Requires two allele for the trait to show
Only bb has blue eyes
Genotype
Gene type
What a person’s alleles (letters) are BB Bb bb
Phenotype
Physical type
What a person looks like
Blue eyes
Heterozygous
Hybrid
Carrier
Having 2 alleles that are different
Homozygous
Pure bred
Pure breeding
True bred
True breeding
Having 2 alleles that are the same

2. Punnett Square Notes Using the diagram above, see if
Punnett Squares are used to predict the genotypes and phenotypes of the
potential offspring produced by a cross (mating).
Allele carried by father’s sperm goes here
This is a monohybrid cross,
because we are only looking
at the results of one trait.
The mother and the father are
considered the P generation.
Allele carried by mother’s egg goes here
Using the diagram above, see if
you can fill in the Punnett square
To the left.

3. Punnett Square Generations
Fill in the Punnett Square below for
the parental cross and F1 offspring
Fill in the Punnett Square below for
the F1 cross and F2 offspring

4. Punnett Square Ratios & Percentages
T = tall (dominant) t = short (recessive)
Generation
Punnett Square
Genotypes &
Percentages
Genotypes
&
Ratios
Phenotypes
& Percentages
Phenotypes &
Parental Cross
F1 Generation (offspring)
F1 Cross
F2 Generation
(offspring)