What happens to cells when placed in a saltwater solution?

When the plant cells are placed in the salt solution, there is a higher concentration of water molecules in the cell and a lower concentration of water in the salt solution and thus a concentration gradient has been set up. Therefore, water moves out of the cell across the partially permeable membrane by osmosis and the cell becomes flaccid as the cell membrane peels away from the cell wall. Contrastingly, when the plant cells are placed in distilled water, the concentration of water molecules is greater out of the cell than it is in the cell and therefore water moves into the cell by osmosis down the concentration gradient. The cell membrane is now pressed up against the cell wall and the cell is said to be turgid.

Introduction
Osmosis is the physo-chemical process resulted from pressure differences.

Example of this principle is found on physiology on the celebrated Fick's law. Further, cells in general use this physical phenomenon for transporting important molecules in and out of the cells in what is named passive transport, no energy is demanded, no proteins is used for the job.

In the scheme below, mass will go from the high concentration side, left, to low concentration, right. It will go on until the concentrations will meet.

Discussions

Blood cells are composed mainly of water, it will make up the proportion of about 90% of water for whole body. One nice example is when we remain too much time in the pool or sea water, our skin will change its normal state.

Because of the difference in osmotic potential caused by the salt water solution, water will diffuse out of the red blood cells causing them to shrink in size. Accordingly, this principle is used in the curing(*) of meat and vegetables; most of the bacteria will have their cells destroyed due the "water-stealing process."

Therefore, when we place blood red cells within a salty solution, pressure generated by concentration differences, of salt, higher outside, will make salt come in, due to cell-self protection mechanisms, not too much, and water will come out, eventually the cell can "crack." It can be seen for instance when a frog gets in touch with salt by the skin, they loose the skin-need humidity. On the upcoming picture, we have an schematic picture of a shrivelled cell.

Picture 1 Shrivelled cells, accessed on 11 02 2016

Notes.
(*) Curing is the addition to meats of some combination of salt, sugar, nitrite and/or nitrate for the purposes of preservation, flavor and color. http://nchfp.uga.edu/publications/nchfp/lit_rev/cure_smoke_cure.html. accessed on 10 02 2016.

By Bonnie Crowe

Osmosis is the movement of water across a membrane. Salt triggers osmosis by attracting the water and causing it to move toward it, across the membrane. Salt is a solute. When you add water to a solute, it diffuses, spreading out the concentration of salt, creating a solution. If the concentration of salt inside a cell is the same as the concentration of salt outside the cell, the water level will stay the same, creating an isotonic solution. Cells will not gain or lose water if placed in an isotonic solution.

Water in cells moves toward the highest concentration of salt. If there is more salt in a cell than outside it, the water will move through the membrane into the cell, causing it to increase in size, swelling up as the water fills the cell in its imperative to combine with the salt. If a higher concentration of salt is placed outside of the cell membrane, the water will leave the cell to bond with it. The loss of water from this movement causes plant cells to shrink and wilt. This is why salt can kill plants; it leaches the water from the cells. The movement of water to leave an animal cell will also cause those cells to shrink and cause dehydration. This is why a person could die from dehydration if he drinks enough sea water.