The outermost layer that forms a boundary around the outside of each cell is called the cell membrane , also known as the plasma membrane or plasmalemma. This membrane surrounds the cytoplasm of all living cells, separating and protecting the interior of the cell from the external environment. It is a semi-permeable lipid bilayer embedded with proteins, which regulates the movement of substances in and out of the cell, maintaining the cell's internal environment and facilitating communication and adhesion with other cells
. For plant cells and some other organisms, there is an additional outer layer called the cell wall outside the cell membrane, which provides extra structural support and protection. The cell wall itself has layers, with the primary cell wall being the outermost layer of the cell wall structure
. Summary:
Cell Type| Outermost Layer Name| Description
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Animal cells| Cell membrane| Flexible lipid bilayer controlling entry/exit of
substances
Plant cells| Cell wall (Primary wall)| Rigid structure outside the cell
membrane providing support
Final answer: The outermost layer around the outside of each cell is the cell membrane (plasma membrane) in animal cells, and the primary cell wall in plant cells
