Punnett Square practice worksheet for 9th grade biology

🧬 Topic Summary

A Punnett square is a diagram used in biology to predict the outcome of a particular cross or breeding experiment. It's a visual tool that helps determine the probability of offspring inheriting specific traits. By organizing the possible combinations of alleles from each parent, it simplifies understanding genetic inheritance patterns.

This worksheet is designed to provide you with practice in using Punnett squares to predict the genotypes and phenotypes of offspring based on the genotypes of their parents. It will cover basic Mendelian genetics and help you understand concepts like dominant and recessive alleles, homozygous and heterozygous genotypes.

🗂️ Part A: Vocabulary

Match each term with its definition:

1. Term: Genotype
2. Term: Phenotype
3. Term: Allele
4. Term: Homozygous
5. Term: Heterozygous

1. Definition: Having two different alleles for a trait.
2. Definition: The genetic makeup of an organism.
3. Definition: The physical expression of a trait.
4. Definition: One of two or more versions of a gene.
5. Definition: Having two identical alleles for a trait.

✏️ Part B: Fill in the Blanks

Complete the following paragraph using the words provided: dominant, recessive, Punnett square, trait, gene.

A __________ is a chart used to predict the possible genotypes of offspring in a genetic cross. Each __________ controls a specific ___________. If an allele is __________, it will be expressed even if only one copy is present. A __________ allele, on the other hand, will only be expressed if two copies are present.

🤔 Part C: Critical Thinking

Explain how understanding Punnett squares can be useful in fields like agriculture or medicine. Provide specific examples.