How do substances like `CO_(2)` and water move in and out of the cell ? Discuss.

Explanation

The movement of `CO_(2)` and water occurs by diffusion and osmosis respectively.
(2) These processes take place due to selectively permeable plasma membrane.
(3) During cellular respiration, the concentration of `CO_(2)` increases inside the cell. As against this the concentration of `CO_(2)` outside the cell is lesser.
(4) When there is such a difference in the concentration of `CO_(2)` inside and outside of the cell, then diffusion takes place. (5) The `CO_(2)` moves from region of higher concentration to region of lower concentration through the plasma membrane of the cell. The cell having higher concentration of `CO_(2)` thus gives it out by the process of diffusion.
(6) In the same way `CO_(2)` enters the cell as the outside of the cell has higher concentration of O, than the inside of the cells.
(7) Similarly water also undergoes the process of osmosis. Water passes from region of higher water concentration to the region of lower water concentration through the plasma membrane. However, the osmosis also depends upon the amount of substances dissolved in the water.