Florida Biology EOC Practice Test

The cell wall is the structure that protects and provides shape to plant cells. It is composed mainly of cellulose, which is a carbohydrate that forms a rigid framework around the cell membrane. This rigidity is crucial for maintaining the cell's shape, especially since plant cells often encounter varying moisture conditions and mechanical stresses.

Furthermore, the cell wall serves as a protective barrier against pathogens and mechanical damage, contributing to the overall integrity of the plant. Unlike the cell membrane, which regulates the entry and exit of substances, the cell wall is more about structural support and protection. This structural role is essential for plants, allowing them to grow tall and remain upright, which is vital for their ability to capture sunlight for photosynthesis. The other structures listed, while important for different functions within the cell, do not provide the same combination of support and protection that the cell wall offers.