Multiple choice Which of the following organelles make the endoplasmic reticulum rough? Ribosomes Lysosomes Vacuoles Cytoplasm Cytosol Reveal answer Fill a bubble to check yourself A Correct answer Explanation Ribosomes are small granules that synthesize proteins. Endoplasmic reticulum is the protein synthesizing site of the cell. Ribosomes make the endoplasmic reticulum rough.