AEMCA Practice Exam

Which cellular organelle is responsible for energy production?

1. Nucleus

2. Mitochondrion

3. Golgi apparatus

4. Lysosomes

The correct answer is: Mitochondrion

The mitochondrion is known as the powerhouse of the cell primarily because it is the organelle responsible for energy production. It facilitates the process of cellular respiration, where nutrients such as glucose are converted into adenosine triphosphate (ATP), the energy currency of the cell. This process occurs through a series of biochemical reactions, including the Krebs cycle and oxidative phosphorylation, which takes place across the inner mitochondrial membrane. The efficiency of ATP production and the ability to harness energy from various substrates make mitochondria vital for the energy needs of the cell. In contrast, other organelles serve different essential functions. The nucleus is mainly involved in storing genetic material and coordinating cell activities such as growth and reproduction. The Golgi apparatus is responsible for modifying, packaging, and distributing proteins and lipids synthesized in the endoplasmic reticulum, while lysosomes contain enzymes for breaking down cellular waste and recycling material. Each of these organelles contributes to cellular function but does not play a direct role in energy production like the mitochondrion does.