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

What are mutations in DNA primarily responsible for?

1. Alterations in protein structure only

2. Inheritable changes that serve as the basis of evolution

3. Only detrimental changes affecting organisms

4. Non-inheritable adaptations to the environment

The correct answer is: Inheritable changes that serve as the basis of evolution

Mutations in DNA are primarily responsible for inheritable changes that serve as the basis of evolution. This is because mutations introduce new genetic variations into a population's gene pool, which can lead to changes in traits that may provide an advantage or disadvantage in a given environment. Over time, these genetic variations can accumulate and lead to the evolution of new species or adaptations, ultimately contributing to the diversity of life. Inheritable mutations can be passed down from one generation to the next, allowing for the potential evolution of populations as these changes are subject to natural selection and other evolutionary mechanisms. Beneficial mutations may increase an organism's fitness, while neutral or detrimental mutations can still contribute to genetic diversity. While alterations in protein structure are one consequence of mutations, they are not the sole outcome, as mutations can affect regulatory regions, RNA molecules, and other genomic elements that may not directly translate to changes in protein structure. Thus, focusing solely on protein structure overlooks the broader evolutionary implications of inheritable changes in DNA. Similarly, mutations are not only detrimental—many can be neutral or beneficial, contributing positively to the organism's adaptability and fitness in its environment. Non-inheritable adaptations typically arise from environmental interactions rather than genetic mutations, further emphasizing the unique role mutations play in