Cell wall is not present in cells of

A cell wall is a rigid, protective outer layer found in specific organisms to provide structural integrity and protection. In plants, the cell wall is primarily composed of cellulose, which provides rigidity and strength [3]. Fungal cell walls are characterized by the presence of chitin [1]. Bacteria also possess cell walls, typically made of a unique polymer called peptidoglycan (or murein), which protects them from osmotic lysis [2]. In contrast, animal cells, including those of humans, lack a cell wall entirely [1]. Instead, human cells are enclosed only by a flexible cell membrane, allowing for greater mobility and flexibility compared to the rigid structures of plants and microbes [1]. This absence of a cell wall is a fundamental distinguishing feature between animalia and other kingdoms like plantae, fungi, and monera.

Sources

1. [3] https://www.sciencedirect.com/topics/medicine-and-dentistry/cell-wall
2. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > 2.5 Why Is Cell Considered to Be a Basic Unit of Life? > p. 24
3. [2] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 2: The Invisible Living World: Beyond Our Naked Eye > Activity 2.3: Let us investigate > p. 13