Final answer:
The organelle that is continuous with the nuclear envelope and structured by microtubules is the endoplasmic reticulum. It is a key part of the cell's endomembrane system, enabling production, packaging, and export of cellular products and protein synthesis with its rough surface.
Step-by-step explanation:
The organelle that is usually continuous with the nuclear envelope and structured by microtubules is the endoplasmic reticulum (ER). The ER is a pivotal component of the cell's endomembrane system, which is responsible for various cellular functions, including the production, packaging, and export of cellular products.
Furthermore, the rough endoplasmic reticulum (RER) is studded with ribosomes on its surface, playing a crucial role in protein synthesis. These proteins can then be transported through the ER to other parts of the cell for further modification and use.