College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Why do red blood cells not use the oxygen they carry?

1. They lack hemoglobin

2. They lack mitochondria and derive their energy from glycolysis

3. They have a low affinity for oxygen

4. They metabolize anaerobically

The correct answer is: They lack mitochondria and derive their energy from glycolysis

The reason red blood cells do not use the oxygen they carry is that they lack mitochondria and rely on anaerobic metabolism for their energy needs. Since mitochondria are the organelles responsible for aerobic metabolism, which uses oxygen to generate energy, the absence of these structures forces red blood cells to operate without utilizing oxygen for energy production. Instead, they derive their energy through glycolysis, a process that converts glucose into energy without consuming oxygen. This design allows red blood cells to effectively transport oxygen throughout the body without consuming any of it, ensuring that the tissues that need oxygen have the highest possible amount available. The focus on anaerobic metabolism also explains why red blood cells can efficiently remain functional over their lifespan while maintaining the ability to carry oxygen to various tissues.