Tag: biology

While preparing coffee or tea we pour coffee or tea powder at one point but it is uniformly sweet. It is due to diffusion of the solvent from the high concentration to lower concentration and it becomes uniformly sweet taste.

The movement of solutes from lower to higher concentration is called as osmosis. Isotonic solutions are those in which concentration of solute and solvent are same in the outside as well as inside of cells. When cells are placed in the isotonic solution they will remain unaffected as water movement in and out of the cells will be the same . while in hypotonic solution cells will absorb more water and thus become swollen and will burst eventually.

Hypotonic solution is a solution having lower osmotic pressure i.e; having less solute and more water than other solutions. When a cell is placed in hypotonic solution water enters towards the higher concentration i.e., from cell to surrounding as the cell is hypertonic.

PCBs are very stable mixtures that are resistant to extreme temperature and pressure. In general, PCBs are relatively insoluble in water, and the solubility decreases with increased chlorination. PCBs are also freely soluble in nonpolar organic solvents and biological lipids. They have high solubilities in most organic solvents, oils, and fats. 

Plant cells are surrounded by a dead cellulosic cell wall. The plant cell wall is fully permeable and cannot regulate the entry or exit of solutes or solvent. When a plant cell is present in a hypertonic solution plant cell will lose water through exosmosis. As the plant cell keeps on losing water, the protoplasm shrinks and moves away from the cell wall, the hypertonic solution moves inside the space between cell protoplasm and cell wall. 

If the solute concentration is higher in the external solution than the cell kept in it, then the solution is called as hypertonic. When a cell is kept in hypertonic solution then the cell shrinks, as water comes out of the cell.

Cells are plasmolysed (plasmolysis has occurred) when the cell contents shrink and come out from the cell wall. 

If there is a higher concentration of dissolved salt outside of the cell (a hypertonic environment), then H$ _2$O will diffuse "out" from the cell and the cell will shrink and cellular metabolism will cease. This phenomenon is called as plasmolysis and it is the reason why foods can be preserved with high concentrations of salt and sugar.

Soap contains large amount of solutes. Soap is a hypertonic solution with high amounts of salts. Hence, when washing clothes solute concentration is more in soap water than in cells of hand. Due to this, exosmosis occurs in which the water molecules present in cells of hand move out in soap solution. This is an osmotic process in which the water molecules move from lower solute concentration to higher solute concentration, i.e., from dilute solutions to concentrated solution through a semi-permeable membrane. 

In the isotonic solution, the concentration of solvent and solutes of the solution is same as in the cytoplasm of the specific cell. This state allows the free movement of molecules across the membrane without changing the concentration of solutes on either side. Thus, the correct answer is option A.

A Hypertonic solution is a solution with a higher concentration of solutes greater on outside the cell than inside. Since the concentration of water is higher within the cell, there is a net movement of water from inside to outside of the cell (water leaves the cell by osmosis). This causes the cell to shrink as its internal pressure decreases. Thus, the correct answer is option C.