Answer:
The plasma membrane, also known as the cell membrane, serves as a selectively permeable barrier for the cell. This means that some things are allowed to pass in the cell and somethings are allowed to pass out. For example, the cell will let in vital nutrients and it will let out waste. Every organelle inside a eukaryotic cell is surrounded by a membrane. These membranes also serve as selectively permeable membranes. The membranes are made up of lipids and contain a variety of proteins.
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