Summary. The plant body is composed of cells and their products. All plant cells are surrounded by a rigid cell wall that is produced by the cell. Inside the wall is the cell membrane, which selectively regulates the movement of materials into and out of the cells.Plant cells are compartmentalized into organelles that are structurally organized to support their function.The nucleus, chloroplast, ribosomes, and vacuole are examples of plant cell organelles.nside the wall is the cell membrane, which selectively regulates the movement of materials into and out of the cells. Plant cells are compartmentalized into organelles that are structurally organized to support their function. The nucleus, chloroplast, ribosomes, and vacuole are examples of plant cell organelles.