DOC Livingston Public Schools / LPS Homepage Use the diagrams to answer the questions. 3. Which structure is found in a plant cell but not in an animal cell? Circle the correct answer. chloroplast cell membrane ribosome. 4. What is the main function of vacuoles? Store water, salts, proteins and carbohydrates. HW #2 Comparing Animal, Plant and Prokaryotic Cells. Read section 7.2 in your ...