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

Which organelle is responsible for ATP production in cells?

1. Mitochondria

2. Plastids

3. Vacuoles

4. Cytoskeleton

The correct answer is: Mitochondria

The organelle responsible for ATP production in cells is the mitochondria. Mitochondria are often referred to as the "powerhouses" of the cell because they are the site of cellular respiration, a process that generates ATP (adenosine triphosphate), the energy currency of the cell. During cellular respiration, mitochondria convert the energy stored in glucose and other molecules into ATP through a series of biochemical reactions, including glycolysis, the citric acid cycle, and oxidative phosphorylation. When considering the other organelles: plastids are involved in photosynthesis and the synthesis of important molecules like starch in plant cells, vacuoles primarily serve as storage structures for substances such as water, ions, and waste products, and the cytoskeleton provides structural support and helps with cellular movement but does not produce ATP. Thus, the unique function of mitochondria in energy conversion sets them apart and confirms their critical role in ATP production.