Animal Cell Structure The cell membrane, nucleus, cytoplasm, and everything in between. Golgi apparatus Nucleus This houses the cell's DNA. It directs the synthesis of ribosomes and proteins. A series of flattened sacs that helps sorts proteins synthesized in the rough endoplastic reticulum. Cytoplasm A gel-like substance that fills the spaces inside the cell to help retain its form. Endoplastic Reticulum It is a series of folded membranes in the cell that move materials around. Mitochondrion The mitochondrion makes a compound from the broken chemical bonds of food molecules (like sugar) called adenosine triphosphate (ATP) and is stored here until needed. It is also known as the "powerhouse of the cell." Smooth Endoplastic Reticulum It has no ribosomes and helps modify protein made by the rough ER. Lysosome Rough Endoplastic Reticulum It is a vesicle that has digestive enzymes that break down components the cell doesn't need. It also kills bacteria that attacks the body. It has ribosomes attached to it and it creates protein. Cell Membrane This is the thin outer covering that separates the contents of the cell from other cells. It also controls what materials go in and out of the cell. Also known as plasma membrane. Vacuoles These are membranous sacs that are used for storing other things in the cells.