Michigan Test for Teacher Certification (MTTC) Secondary Integrated Science Practice test

What describes a monohybrid cross?

1. A cross that involves two traits

2. A cross that uses only one trait

3. A cross that shows possible gene combinations

4. A cross between homozygous organisms

The correct answer is: A cross that uses only one trait

A monohybrid cross specifically refers to a genetic cross that examines the inheritance of a single trait. In this type of cross, the focus is on the alleles that govern one particular characteristic, such as flower color or seed shape in plants. This method allows for the prediction of offspring genotypes and phenotypes based on the combinations of alleles inherited from the parent organisms. In a monohybrid cross, typically one parent is homozygous for one allele (such as dominant) and the other parent is homozygous for the alternate allele (such as recessive). This setup facilitates the study of how one trait is passed down through generations without the influence of other traits, hence the term "mono," meaning one. It provides a clear example of Mendel's laws of inheritance and simplifies the observation of patterns in genetic contribution. The idea that a monohybrid cross involves only one trait highlights its foundational role in understanding basic genetic principles, making it critical for students learning genetics, particularly in the context of how traits are inherited.