Which is absent in RBC ?

Options

A. Aerobic respiration
B. Cytoplasm
C. mRNA
D. Membrane

Answer

### Step-by-Step Solution:

1. **Understanding RBCs**: Red Blood Cells (RBCs), also known as erythrocytes, are specialized cells responsible for transporting oxygen throughout the body. They are characterized by their red color, which is due to the presence of hemoglobin.

2. **Structure of RBCs**: Mature RBCs are unique in that they lack a nucleus and organelles. This adaptation allows them to maximize space for hemoglobin, enhancing their oxygen-carrying capacity.

3. **Metabolism in RBCs**: Due to the absence of organelles, mature RBCs do not carry out typical metabolic processes. They do not have the machinery required for aerobic respiration, which typically occurs in mitochondria.

4. **Analyzing the Options**: The question provides four options: aerobic respiration, cytoplasm, mRNA, and membrane.
- **Cytoplasm**: Present in RBCs.
- **mRNA**: Present in RBCs, as it is necessary for protein synthesis during their development.
- **Membrane**: Present in RBCs, as they are enclosed by a plasma membrane.
- **Aerobic Respiration**: Absent in mature RBCs due to the lack of mitochondria.

5. **Conclusion**: The component that is absent in mature RBCs is **aerobic respiration**.