Cell wall

Cell wall: is the outermost layer of plant cells, exclusive to plants, fungi, bacteria, and some algae. Composed mainly of cellulose, hemicellulose, lignin, and pectin, it provides protection against physical damage and pathogens, regulates cell growth direction, maintains cell shape and strength, and serves as a storage unit for carbohydrates, particularly in seeds. Additionally, the cell wall permits the free entry of smaller molecules.