Punnett Squares Practice

Punnett Squares Practice

Read each question carefully and use the provided Punnett squares or draw your own to determine the possible genotypes and phenotypes of offspring.

1. What is a Punnett Square used for?

2. An organism's genetic makeup is called its  , while its observable traits are called its  .

3. A   allele will always be expressed if present, while a   allele is only expressed if two copies are present.

4. In pea plants, tall (T) is dominant over short (t). Cross a homozygous dominant tall plant with a homozygous recessive short plant. What are the genotypes and phenotypes of the offspring?

Offspring Genotypes:

Offspring Phenotypes:

5. In guinea pigs, black fur (B) is dominant over white fur (b). If you cross two heterozygous black guinea pigs, what percentage of the offspring will have white fur?

Percentage of white fur offspring:

6. If an organism has two different alleles for a trait (e.g., Tt), it is considered:

7. A Punnett square can predict the exact number of offspring with a certain trait.