My biology book says that "because a cell is filled with salts, proteins, sugars, and other molecules it will

Question

always be hypertonic to fresh water. That means that osmotic pressure should produce a net movement of water into a typical cell that is surrounded be fresh water. If this happens the volume of the cell will increase until it becomes swollen" if it's hypertonic, shouldn't it come out not go in???

Answer 1

Nope. Hypertonic=draws water in. Hypotonic=excess water. Isotonic=balanced. I remember it because "hyper" means a lot, as in a lot of molecules to attract water.

Answer 2

The above answers are right; here's another thing to keep in mind that might clear things up for you a little more. Everything, not just water, will want to go down a concentration gradient (from high to low). Basically, when you have two differing solutions in contact with each other, they will want to equilibrate and become the same solution. However, most of the salts/proteins/sugars etc. inside of a cell can't come out across the plasma membrane (at least not very quickly). Therefore when a cell is in fresh water the only thing that can happen to make the inside environment more like the outside environment is for water to go into the cell and dilute it so much that it's almost as pure as the water outside. Make sense?

Answer 3

Hypertonic, isotonic and hypotonic is about the amount of particles such as salts in a solution not water molecules. Lets say you dissolve 10grams of salt in an 8oz glass of water and 20 grams of salt in another 8oz glass of water. You will have more salt particles in the second glass comparing to the first one, therefore the solution in your 2nd glass is hypertonic comparing to the 1st glass. Now if you grab a 3rd 8oz glass of water and dissolve 30 grams of salt in it, both your 1st and 2nd glasses will be hypotonic relative to the 3rd glass.
Hypertonic, isotonic and hypotonic are relative words. If a solution is hypertonic relative to water, as n cell cytoplasm, it means it has more particles and less water molecule comparing to fresh water, therefore it has a higher concentration of particles and a lees concentration of water than fresh water. According to osmosis, water moves from areas of higher concentration (of water) to areas of lower concentration (of water). In this case, fresh water in the environment has a higher concentration than inside the cell, therefore it moves from outside to the inside of the cell, causing it to swell and even to erupt.

Answer 4

No. The concentration of water to solute inside the cell is lower than it is in fresh water.

Therefore, the water with travel from high concentration of water to solute (higher amount of water: ie fresh water) to that of low concentration of water to solute (lower amount of water: ie in the cell).

Remember that water goes from high concentration to low concentration, so the water will travel into the cell.