List two organelles that are not membrane-bound?

Two organelles that are not membrane-bound are ribosomes and the cytoskeleton. Ribosomes are responsible for protein synthesis and can be found freely floating in the cytoplasm or attached to the endoplasmic reticulum. The cytoskeleton provides structural support and shape to the cell, composed of protein filaments such as microtubules, microfilaments, and intermediate filaments.