Which structure serves as a protective barrier surrounding plant cells?

The cell wall serves as a protective barrier surrounding plant cells. This rigid structure is primarily composed of cellulose, a carbohydrate that provides strength and support. The cell wall gives the plant its shape and protects it from mechanical stress and pathogens, while also regulating the amount of water that enters and exits the cell.

Unlike the cell membrane, which is flexible and regulates the flow of substances in and out of the cell, the cell wall provides a sturdy exterior that helps maintain cellular integrity. The cytoplasm, on the other hand, is the gel-like substance within the cell that contains organelles but does not provide a structural barrier. The nuclear envelope is specifically the double membrane surrounding the nucleus, protecting the genetic material, but it does not encompass the entire cell. Thus, the cell wall is crucial for plant cells in maintaining their structure and function.