GED Science Practice 2025 – 400 Free Practice Questions to Pass the Exam

The strong layer surrounding the cell membrane in plants, algae, and some bacteria is known as the cell wall. This structure serves several important functions: it provides rigidity and support to the cell, helping it maintain its shape, and it also protects the cell from mechanical stress and osmotic pressure. The cell wall is primarily composed of cellulose in plants and algae, which is a polysaccharide that adds to its structural integrity. In the case of bacteria, the composition may vary; many have cell walls made of peptidoglycan.

In plants and algae, the cell wall plays a crucial role in enabling them to withstand environmental pressures, such as wind and water. It allows plants to grow tall and remain upright without collapsing under their own weight. The presence of the cell wall distinguishes plant cells from animal cells, which do not have cell walls but rely solely on the cell membrane for protection and structural support.

While chitin is a strong biopolymer found in the exoskeletons of arthropods and in fungi, and chloroplasts are the sites of photosynthesis within plant cells, they do not serve as the protective or structural layer that the cell wall does. Consequently, the correct answer highlights the specific role and differentiation of the cell wall