Check Your Understanding Question 4.3 Homework Unanswered As erythrocytes (red blood cells) mature, they gradually lose their nuclei and most other organelles. What processes are mature erythrocytes unable to carry out due to a lack of: a) Nucleus b) Mitochondria c) Lysosomes d) Centrioles
The Correct Answer and Explanation is:
a) Nucleus
Without a nucleus, mature erythrocytes are unable to carry out transcription and translation processes. This means they cannot synthesize new proteins or replicate DNA. The loss of the nucleus is an adaptation that maximizes space for hemoglobin, the protein responsible for oxygen transport. However, it also means that once erythrocytes mature, they cannot repair themselves or respond to certain signals that would require protein synthesis.
b) Mitochondria
The absence of mitochondria in mature erythrocytes prevents them from performing oxidative phosphorylation to generate ATP. As a result, erythrocytes rely solely on anaerobic glycolysis for energy production, which is less efficient but sufficient for their function. The lack of mitochondria also means that erythrocytes cannot undergo aerobic respiration, which would otherwise provide more energy for processes like active transport and biosynthesis.
c) Lysosomes
Lysosomes are responsible for breaking down cellular waste and recycling old or damaged organelles. Without lysosomes, mature erythrocytes are unable to carry out autophagy or degrade cellular debris. This limits their ability to clear out damaged components within the cell. However, since erythrocytes are relatively short-lived, the lack of lysosomes is not a major issue as they do not perform extensive self-maintenance during their lifespan.
d) Centrioles
Centrioles are essential for cell division and the formation of the mitotic spindle. Since mature erythrocytes are anucleate and do not divide, they do not need centrioles. The lack of centrioles is consistent with their role as terminally differentiated cells that no longer undergo cell division. However, the absence of centrioles in erythrocytes means they cannot participate in processes such as mitosis or meiosis.
In summary, the loss of key organelles in mature erythrocytes reflects their specialized function of oxygen transport rather than cellular maintenance or division.
