During one stage of malaria infection, the malarial protists enter red blood cells and cause them to burst. Explain why the bursting of red blood cells causes tiredness.

The primary function of red blood cells is to transport oxygen from the lungs to the rest of the body. They are able to do this because they are packed with a protein called haemoglobin, which binds to oxygen. When the malarial protists cause red blood cells to burst, the number of circulating red blood cells decreases (a condition called anaemia). This reduces the overall oxygen-carrying capacity of the blood. Consequently, the body's tissues and muscles receive less oxygen. Oxygen is essential for aerobic respiration, the process that releases the energy needed for all life processes. With less oxygen available, the rate of aerobic respiration slows down, less energy is released, and this results in the symptom of tiredness or fatigue.