why do plant cells have cell wall while animal cells do not...????
Cell wall is a tough and rigid layer around the cell of certain organisms like plants and bacteria, which provides structural support and protects the cells. It is not necessary for animal cells to have a cell wall due to a various reasons like,
1) Animal cells have other forms of support like exoskeleton and endoskeleton. While plant cells do not have these, so they require cell wall.
2) Animal cells can regulate osmotic pressure by pumping ions and salts across the cell membrane. So, they do not require cell wall to protect themselves from bursting due to endosmosis.
3) Animal cells require flexibility for function and movement. This would not be possible if cells have cell wall as it would restricts flexibility.
Cells walls are supporting structures that helps the plant to have a fixed shape and protect it from injury. Plant cell need cell walls to maintain shape, structure and rigidity. Animal cells does not need the support that plant cell was provided with because animals have other forms of support and the lack of the cell wall allows increaced flexibility
There are a number of reasons:
Plants cannot move and thus require more protection than animals (unicellular and multi-cellular) which are able to move away from danger. Cell walls provide structural strength against mechanical damage as well as invasion from fungi and bacterial pathogens.
Plants do not have a central or exoskeleton like animals and insects and have to rely on internal structural strength to support themselves. This enables them to grow towards light, water or nutrient sources.
Plant cells need a cell wall to maintain shape, structure and rigidity. Animal cells don't need cell walls because they have micro filaments and micro tubules to hold the shape of the cell.
The cell wall of the plant cell is made up of cellulose. Cellulose is a complex carbohydrate.