Heterophagosome is

Options

A. Formed by fusion of food containing phagosome with primary lysosome
B. A newly pinched out vesicle from Golgi apparatus which fuses with endosome to become fully functional
C. Formed by fusion of primary lysosome with degenerating intracellular organelles
D. A lysosome in which only indigestible food material is left

Explanation

### Step-by-Step Solution for the Question: "Heterophagosome is"

1. **Definition of Heterophagosome**:
A heterophagosome is a type of cellular structure formed when a phagosome, which contains engulfed food particles, fuses with a primary lysosome.

2. **Formation Process**:
- **Phagosome Formation**: When a cell engulfs food material, it forms a vesicle known as a phagosome.
- **Primary Lysosome**: This is a vesicle that is pinched off from the Golgi apparatus and contains inactive hydrolytic enzymes.
- **Fusion**: The phagosome then fuses with the primary lysosome, leading to the formation of a heterophagosome.

3. **Function of Heterophagosome**:
- The heterophagosome contains hydrolytic enzymes that help in breaking down the engulfed food material.
- This process allows the cell to digest and utilize nutrients from the food particles.

4. **Further Development**:
- After digestion, any indigestible material left in the heterophagosome can lead to the formation of a tertiary lysosome.

5. **Comparison with Other Structures**:
- It is important to differentiate heterophagosomes from autophagosomes, which are formed when a phagosome fuses with a primary lysosome containing cellular debris or organelles.

### Summary:
In summary, a heterophagosome is a membrane-bound structure formed by the fusion of a food-containing phagosome with a primary lysosome, allowing for the digestion of engulfed materials.

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