Question

an important organelle is missing from this image of a eukaryotic cell undergoing protein synthesis. this organelle is not surrounded by a membrane but sits in the nucleus. it produces ribosomal subunits from proteins and ribosomal rna, which is exported into the cell proper. it is key to the process of protein synthesis taking place at ribosomes. what is this organelle? a centriole b centrosome c mitochondria d nucleolus

Explanation:

The nucleolus is a non - membrane bound organelle in the nucleus. It synthesizes ribosomal subunits from proteins and ribosomal RNA and is crucial for protein synthesis at ribosomes. Centrioles and centrosomes are related to cell division and not to protein synthesis as described. Mitochondria are the power - houses of the cell and not involved in producing ribosomal subunits.

Answer:

D. nucleolus