Question

What is the appropriate difference between plant cell and animal cell?
A. Plant cell- cell wall is present, Animal- cell wall is absent
B. Plant cell- cell wall is absent, Animal- cell wall is present
C. Plant cell- cell wall is present, Animal- cell wall is present
D. Plant cell- cell wall is absent, Animal- cell wall is absent

Answer 1

A cell wall is a structure which surrounds the cells and is present just outside the cell membrane. It can be of various types like- tough, flexible or rigid. It is responsible for providing both structural support and protective function to the cell and also acts as a sieve. The cell wall is composed of various substances. Its composition depends on the organism.

Complete answer:
Cell wall is mostly found in all prokaryotes (excluding the mollicute bacteria), algae, and fungi. It is present in eukaryotes like plants but the animals are devoid of the cell wall. The major function of a cell wall is to act as pressure vessels because they prevent the cell from over-expanding in case of water entry. The cell wall of the plants is usually made up of the constituents like polysaccharides, cellulose, hemicelluloses and pectin. Often, presence of other polymers like lignin, suberin or cutin is observed either outside or inside the plant cell walls. Due to the presence of the cell wall, the process of cytokinesis takes place by cell plate formation in plant cells unlike animal cells where it takes place by the process of furrow formation. The cell wall prevents the plant cell from bursting due to excess water entry. It provides rigidity and structural framework to the plant cell.

So, the correct option is A which states that plants have cell walls but animals don't.

Additional information:
Other important differences between animal and plant cells are as follows-
Plastids are present in plant cells while absent in animal cells.
Plant cells have distinct boundaries. Animal cells don’t have such clear boundaries.
Centrosomes are present in animal cells but absent in plant cells.
Plant cells have large vacuoles which are not present in animals.

Note:
The cell walls of algae are composed of glycoproteins and polysaccharides, specifically carrageenan and agar. In monerans, the cell wall is made of peptidoglycan. In archaea, it is formed of glycoprotein, peptidoglycan and polysaccharides. Fungi cell walls consist of the NAG polymer known as chitin.