Osmosis and Diffusion in Plant and Animal cells

A) 4. The cell membrane of a plant in a hypotonic solution expands and in a hypertonic solution, the cell membrane shrinks.

5. Cells do not burst when placed in a hypotonic solution because the cell wall does not give way. The cell wall is a strong wall to keep the structure of the cell.

B) 2(a). Nothing happened to the blood cell in a botanic solution

(b). When water is added to the blood cells the cell membrane expands and sometimes bursts

(c). When blood cells are in a hypertonic solution the cell membrane shrivels

4. The blood cells shrank in the hypertonic solution because water left the cell. The blood cells expanded and sometimes burst in the hypotonic solution because there is more water inside the cell than usual, which means there is an abundance of water inside the cell, which is making it hard for the cell membrane to hold it in.


1) Osmosis—a special type of diffusion, the way water moves through a selectively permeable membrane.

Diffusion—movement of molecules from a region of higher concentration to a region of lower concentration.

2) a) solute—substance dissolved in a fluid to form a solution

b) Solvent—fluid that dissolves the solute

c) Brownian movement—is the random movement of particles causes by collisions with molecules

d) Selectively permeable membrane—membrane that will allow only a selected type of materials, others are prevented

e) Osmotic pressure—is the pressure that develops in a system due to osmosis

f) Isotonic—the concentration is the same in two locations

g) Hypotonic—the concentration of the solute is lower than the concentration of the water in the cell

h) Hypertonic—the cell has a higher concentration of solute than the concentration of water

i) Plasmolysis—contraction of the cell contents due to the loss of water

j) Flaccid—is the state of a cell once its plasmolysis the cell membrane becomes limp and soft

k) Cyclosis—a circular flow of protoplasm within the cell walls without affecting the cell membrane

l) Turgor pressure—internal pressure that adds to the strength of a cell and builds up when water moved by osmosis into a cell

m) Concentration gradient –a comparison between two locations

n) Lysis—is the term used to refer to disrupted cells

o) Crenated—refers to red blood cells when they are placed in a hypertonic solution and shrink

p) Dialysis—is the movement of solute through a selectively permeable membrane

3) Molecules move from a region of high concentration to low concentration became due to their random movement they bump together and move to places where there is nothing to bump into. They eventually find their way around became of their random movement.

4) “Bulk flow” is different from diffusion became when there is bulk flow through a membrane than all materials are able to pass through. During diffusion, there is a selectively permeable membrane which allows only retain materials to pass through (high concentration to low concentration, needs energy, ATP used)


1) What effect would putting salt on a slug have? Why?

Putting salt on a slug would suck all the water out of the slug. The water moves from inside of the cell (high concentration of water) to outside of the cell (lower concentration of water) which would make the slug shrivel up and die.

2) Why does throwing salt on the sidewalk in winter sometimes kill nearby plants?

Throwing salt on the sidewalks during the winter kills plants nearby because the cells in plants dry up due to the abundance of salt sucking the water out of the plant cells.

3) How does diffusion play an essential role in the life of plant or animal cell?

Diffusion plays an essential role in like of a plant or animal cell because it is an easy/non-energy way to get nutrients and materials to pass through the membrane. In addition, diffusion occurs through a selectively permeable membrane, so the things that could be harmful to the plant or animal will not be able to pass through the membrane.

4) Beaker A contains an 8% sucrose solution while Beaker B contains a 9% sucrose solution. Is the solution in Beaker A hypotonic or hypertonic to the solution in Beaker B? Explain.

The solution in Beaker A is hypotonic because the 8% sucrose solution has a higher concentration of water than the