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

What does an inborn error of metabolism typically arise from?

1. A mutation in chromosomal structure

2. A defective gene coding for an enzyme

3. Polygenic inheritance

4. A genetic linkage disorder

The correct answer is: A defective gene coding for an enzyme

An inborn error of metabolism typically arises from a defective gene coding for an enzyme. This means that when there is a mutation or alteration in a gene responsible for producing a specific enzyme, it can disrupt metabolic pathways. Enzymes are critical for facilitating biochemical reactions in the body, and a defect can lead to the accumulation of substrates or a deficiency of essential products necessary for metabolism. This can manifest in various metabolic disorders, such as phenylketonuria (PKU) or galactosemia, where specific metabolic processes are hindered due to the absence or dysfunction of a key enzyme. These disorders often require the management of dietary intake or other therapeutic interventions to mitigate the effects of the metabolic disruption. The other options refer to different genetic issues that may cause various disorders or conditions but do not directly relate to the specific mechanism underlying inborn errors of metabolism. A mutation in chromosomal structure generally refers to larger scale genetic changes that may result in physiological conditions or syndromes, polygenic inheritance involves multiple genes contributing to a trait rather than a single enzyme, and genetic linkage disorders pertain to the tendency of genes located close together on a chromosome to be inherited together, which does not specifically describe the metabolic disruptions caused by enzyme defects.