Which of the following cell organelles form more than half of the membranous content of the cell?

Options

A. ER
B. Mitochondria
C. Golgi complex
D. Ribosomes

Answer

To answer the question regarding which cell organelles form more than half of the membranous content of the cell, we can follow these steps:

### Step 1: Identify the Cell Organelles
First, we need to identify the major cell organelles that contribute to the membranous content of the cell. The key organelles to consider are:
- Endoplasmic Reticulum (ER)
- Nucleus
- Mitochondria
- Golgi Apparatus

### Step 2: Understand the Structure of Each Organelle
Next, we need to understand the structure and function of these organelles:
- **Endoplasmic Reticulum (ER)**: This organelle is a network of membranes that extends throughout the cytoplasm. It has two forms: rough ER (with ribosomes) and smooth ER (without ribosomes). The ER is highly membranous and contributes significantly to the total membrane content of the cell.
- **Nucleus**: The nucleus has a double membrane structure known as the nuclear envelope. While it is important, it does not contribute as much to the total membrane content compared to the ER.
- **Mitochondria**: These are double-membraned organelles known as the powerhouse of the cell. They do contribute to the membranous content but not as extensively as the ER.
- **Golgi Apparatus**: This organelle is involved in secretion and packaging. It has membranes but is not as extensive as the ER.

### Step 3: Compare the Membranous Contributions
From the understanding of the structures:
- The **Endoplasmic Reticulum** is the most extensive membranous structure in the cell, forming a significant portion of the total membrane content.
- The **Nucleus**, **Mitochondria**, and **Golgi Apparatus** contribute to the membrane content but to a lesser extent compared to the ER.

### Step 4: Conclusion
Based on the analysis, the **Endoplasmic Reticulum (ER)** forms more than half of the membranous content of the cell.

### Final Answer
The cell organelle that forms more than half of the membranous content of the cell is the **Endoplasmic Reticulum (ER)**.

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