Algonquin College Health Program Assessment (AC-HPAT) Practice Exam

Which organelle is known as the powerhouse of the cell?

1. Lysosome

2. Ribosome

3. Mitochondria

4. Endoplasmic reticulum

The correct answer is: Mitochondria

The mitochondria are known as the powerhouse of the cell because they are responsible for producing adenosine triphosphate (ATP), the primary energy currency of the cell, through a process called oxidative phosphorylation. This process occurs in the inner membrane of the mitochondria, where the electron transport chain generates ATP using energy derived from nutrients. The ability to generate ATP is crucial for powering various cellular functions and processes, including muscle contraction, nerve impulse propagation, and biosynthesis. The other organelles listed serve different functions within the cell. Lysosomes are involved in digestion and waste removal, ribosomes are the sites of protein synthesis, and the endoplasmic reticulum plays a role in the synthesis and processing of proteins and lipids. Each organelle has its distinct purpose, but the mitochondria's unique role in energy production is what earns them the designation "powerhouse."