Final answer:
The 9+2 microtubule model is found in the structure of cilia and flagella, enabling cell movement.
Step-by-step explanation:
The 9+2 microtubule model is a characteristic of cilia and flagella, which are cell organelles responsible for cell movement. These membrane modifications contain nine pairs of microtubules arranged in a circle around two single microtubules in the center. This structure is essential for the movement of cilia and flagella and is distinct from the components found in smooth endoplasmic reticulum, Golgi apparatus, and mitochondria.