5Cell Membrane Structure and Organelles
Cell structures consist of biological membranes - essentially mobile lipid bilayers to which many membrane proteins attach. The cell membrane separates the interior of the cell from the outer environment, acts as a barrier against exterior forces, and regulates the flow of materials and information across the membrane.
Many bacteria, including E. coli, have one biological membrane - the cell membrane. Nucleated cells of organisms such as yeasts, animals and plants have organelles surrounded by biological membranes intertwined with particular proteins, forming a unique intercellular environment. Many intracellular functions operate smoothly through the collaboration of organelles. In addition, biological membranes are not static; they are continuously created and move/fuse together, thus creating flow between membranes. Cells can grow, divide and perform a range of movements thanks to the fluid structure of their membranes.