Organelle X bears ribosomes on its outer surface. Organelle X and organelle Y together give rise to organelle Z which is often referred to as 'suicide bag' of cells
Which of the following organelles is absent in mature mammalian RBCs?

Options

A. X
B. Y
C. Z
D. All of these

Explanation

To solve the question, we need to identify the organelles mentioned and determine which one is absent in mature mammalian red blood cells (RBCs).

### Step-by-Step Solution:

1. **Identify Organelle X**:
- The question states that Organelle X bears ribosomes on its outer surface. This description corresponds to the **Rough Endoplasmic Reticulum (RER)**, which is involved in protein synthesis due to the presence of ribosomes.

**Hint**: Think about which organelle has ribosomes attached to it.

2. **Identify Organelle Y**:
- Organelle Y, when combined with Organelle X, gives rise to Organelle Z. The rough endoplasmic reticulum (X) and the Golgi apparatus (Y) work together in the processing and packaging of proteins.

**Hint**: Consider what organelle is responsible for modifying and packaging proteins after they are synthesized.

3. **Identify Organelle Z**:
- The question states that Organelle Z is often referred to as the 'suicide bag' of the cell. This refers to **Lysosomes**, which contain enzymes that can break down waste materials and cellular debris.

**Hint**: Recall which organelle is known for breaking down waste and is sometimes associated with cell death.

4. **Determine which organelles are absent in mature mammalian RBCs**:
- Mature mammalian red blood cells are unique in that they lack a nucleus and most organelles, including the rough endoplasmic reticulum, Golgi apparatus, and lysosomes. Their primary function is to carry hemoglobin for oxygen transport.

**Hint**: Think about what happens to organelles during the maturation of red blood cells.

5. **Conclusion**:
- Since mature mammalian RBCs lack all of the mentioned organelles (X, Y, and Z), the correct answer to the question is that all of these organelles are absent in mature mammalian RBCs.

### Final Answer:
All of these organelles (X, Y, and Z) are absent in mature mammalian red blood cells.