what are the parts of a cell and how do they work?
 All cells include the following parts: 1 Cell Membrane - forms the outer boundary of the cell and allows only certain materials to move into or out of the cell. 2 Cytoplasm - a gel-like material inside the cell; it contains water and nutrients for the cell. 3 Nucleus - directs the activity of a cell; it contains chromosomes with the DNA. 4 Nuclear Membrane - separates the nucleus from the cytoplasm. 5 Endoplasmic Reticulum - moves materials around in the cell. 