Final answer:
The loss of the nucleus during red blood cell development prevents the cells from dividing and limits their lifespan to around 120 days, but it allows for more hemoglobin and efficient oxygen transport. These cells are ultimately broken down in the liver and spleen.
Step-by-step explanation:
During the development of red blood cells (RBCs), the nucleus is extruded which significantly affects the RBC's longevity and ability to divide. Without a nucleus, an RBC cannot undergo mitosis, which means it cannot divide to produce new cells. Furthermore, lacking other organelles, including a nucleus, allows the RBC to maximize its space for hemoglobin, enhancing its primary function of oxygen transport. This structural adaptation, however, makes the RBCs essentially end-cells with a finite lifespan. After approximately 120 days, aged RBCs are destroyed in the liver and spleen. The loss of the nucleus also affects the RBC's longevity in relation to cellular aging processes such as telomere shortening, which does not occur in non-nucleated cells like mature RBCs.