OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What role do mitochondria play in cells that perform active transport?

1. They store nutrients for energy

2. They facilitate cell division

3. They provide energy through respiration

4. They help maintain cellular shape

The correct answer is: They provide energy through respiration

Mitochondria are often referred to as the "powerhouses" of the cell because they are responsible for producing adenosine triphosphate (ATP) through the process of cellular respiration. Active transport requires energy to move substances against their concentration gradient, and ATP is the primary energy currency used by cells for this purpose. When a cell engages in active transport, it utilizes ATP to fuel transport proteins or pumps embedded in the cell membrane, enabling the movement of ions or molecules from an area of lower concentration to one of higher concentration. Without the energy supplied by the ATP generated in the mitochondria, active transport could not occur efficiently, which is essential for maintaining cellular functions and homeostasis. This understanding emphasizes the critical role mitochondria play not only in providing energy but also in supporting various cellular processes, including active transport.