Which organelle is absent in mature erythrocytes (red blood cells)?

• A. Mitochondria
• B. Ribosomes
• C. Nucleus
• D. Endoplasmic reticulum

Answer: (C)

Verified step by step guidance

1. Understand the function of erythrocytes: Erythrocytes, or red blood cells, are primarily responsible for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide from the body to the lungs.
2. Recognize the unique characteristics of mature erythrocytes: Mature erythrocytes are unique among cells in the human body because they lack certain organelles that are typically present in other cell types.
3. Identify the organelles typically found in cells: Common organelles include the nucleus, mitochondria, ribosomes, and the endoplasmic reticulum. Each of these has specific functions, such as the nucleus housing DNA, mitochondria producing energy, ribosomes synthesizing proteins, and the endoplasmic reticulum being involved in protein and lipid synthesis.
4. Determine which organelle is absent in mature erythrocytes: Mature erythrocytes are known to lack a nucleus, which is a key feature that allows them to have more space to carry hemoglobin, the protein that binds oxygen.
5. Conclude that the absence of a nucleus in mature erythrocytes is a distinguishing feature, as it allows them to efficiently perform their role in oxygen transport without the need for cellular division or protein synthesis.