In humans, which cell type typically contains the greatest number of mitochondria due to exceptionally high ATP demand for continuous contraction?

• A. Adipocyte (fat cell)
• B. Red blood cell (erythrocyte)
• C. Cardiac muscle cell (cardiomyocyte)
• D. Skin keratinocyte

Answer: (C)

Verified step by step guidance

1. Understand the role of mitochondria: Mitochondria are the organelles responsible for producing ATP, the energy currency of the cell, through cellular respiration.
2. Consider the energy demands of each cell type: Cells that require continuous and high amounts of energy will have more mitochondria to meet their ATP needs.
3. Analyze each option: Adipocytes store fat and have moderate energy needs; red blood cells lack mitochondria entirely because they rely on anaerobic metabolism; skin keratinocytes have moderate energy demands for maintenance and repair.
4. Recognize that cardiac muscle cells (cardiomyocytes) contract continuously and require a constant, high supply of ATP to sustain heartbeats without fatigue.
5. Conclude that cardiac muscle cells contain the greatest number of mitochondria to fulfill their exceptionally high ATP demand for continuous contraction.