You've reached the cell wall!The cell wall is a tough, rigid, yet flexible layer that surrounds the cell. It gives the cell structure and protection, and acts as a pressure regulator to make sure that the cell does not become too full with water. It filters out toxins and other things that may harm the cell and doesn't let in strange molecules. It can be composed of up to 3 layers, and is made of cellulose and carbohydrates. They are often structured like baskets. Recent research has shown that certain proteins and RNA are built inside the cell wall, prepared to fight viruses.
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