All living things are composed of cells. They are the building blocks of all life. Cells come in many different shapes and have different functions. Plant and animal cells are different, too. The main difference between plant and animal cells is that plant cells have a cell wall on the outer layer, whereas animal cells only have a cell membrane. The cell wall is a protective layer outside the cell membrane that also provides support for the cell's structure.
Chloroplast, cell wall and vacuole are not present in animals. These are present in only plants.
Functions of cell wall:
* Gives the cell a definite shape and structure.
* Provides structural support.
* Protection against infection and mechanical stress.
* Separates interior of the cell from the outer environment.
* It enables transport of substances and information from the cell insides to the exterior and vice versa.
* Also helps in osmotic-regulation.
* Prevents water loss.
* The physiological and biochemical activity of the cell wall helps in cell-cell communication.
* It prevents the cell from rupturing due to tugor pressure.
* Aids in diffusion of gases in and out of the cell.
* Also provides mechanical protection from insects and pathogens.
The jelly-like fluid that fills a cell is called cytoplasm. It is made up of mostly water and salt. Cytoplasm is present within the cell membrane of all cell types and contains all organelles and cell parts. Cytoplasm has various functions in the cell.
Most of the important activities of the cell occur in the cytoplasm. Cytoplasm contains molecules such as enzymes which are responsible for breaking down waste and also aid in metabolic activity.
Cytoplasm is responsible for giving a cell its shape. It helps to fill out the cell and keeps organelles in their place. Without cytoplasm, the cell would be deflated and materials would not be able to pass easily from one organelle to another.
Cytosol is the part of the cytoplasm that does not contain organelles. Instead, cytosol is confined by the boundaries of a matrix which fills the part of the cell that does not contain organelles.