CBSE Class 9 Answered

Yes, both are considered as cell organelles. Nucleus is a major cell organelle whereas ribosome is a minor cell organelle.

In cell biology, an organelle is a specialized subunit within a cell that has a specific function, and is separately enclosed within its own lipid membrane.

But a dispute regarding ribosome being considered as organelle is as given below:

Not all parts of the cell qualify as organelles, and the use of the term to refer to some structures is disputed. These structures are large assemblies of macromolecules that carry out particular and specialized functions, but they lack membrane boundaries. Such cell structures, which are not formally organelles, include ribosomes and flagellum