Diffusion and Osmosis Worksheet



Diffusion and Osmosis Worksheet

West Aurora High School

Diffusion is the movement of particles from areas of (higher/lower) concentration to areas of (higher/lower) concentration. It is a natural, random process. It (does/does not) require extra energy input.

1 a. These are pictures of molecules frozen at two different times. Draw arrows to show the direction each particle might travel due to diffusion in diagrams A and B.

A. B.

1b. Describe the way the particles of a gas move.

1c. Diagram A shows the same number of particles as in Diagram B except most particles start out on one side of the box. After a while, Diagram A resembles Diagram B. Explain why.

2. Give an everyday example of diffusion in air and in water.

AIR:

WATER:

3. Complete the following sentence: Diffusion is the (purposeful/random)movement of particles from (high/low) concentration to a (high/low) concentration until they are (evenly spread out/concentrated in one area)

4. Moths emit chemicals called pheromones to attract a mate.

a) Which process is responsible for the distribution of these chemicals through the air?

b) If a moth detects pheromones, how might it work out which direction they are coming from?

c) What would be the advantage of a moth releasing the pheromones on a night when there was little wind?

5a. Osmosis is the diffusion of (solutes/water) across a semi permeable membrane. The membrane acts like a filter that lets only the (solutes/water) through. Water always goes from the area of (higher/lower) water concentration to the area of (higher/lower) water concentration.

On the diagram right, label the:

• Semi permeable membrane (M)

• Area of higher solute concentration (HS)

Area of higher water concentration (HW)

• Area of lower solute concentration (LS)

Area of lower water concentration (LW)

• Direction of osmotic flow (arrow)

5b.

▪ The number of water particles on the left hand side (increases/stays the same/decreases)

▪ The concentration of the solution on the right hand side (increases/stays the same/decreases)

▪ The concentration of the solution on the left hand side (increases/stays the same/decreases)

▪ Explain why the concentrations of solution on either side of the semi-permeable membrane change.

6. Water is the substance that moves in osmosis, but solutions are defined by the concentration of (water/solutes).

a. When the solute concentration is the same on both sides of a semi-permeable membrane, the solutions are said to be (isotonic, hypertonic, hypotonic)

b. When the solution on one side of a membrane is higher in concentration than the other, the one with higher solutes is called (isotonic, hypertonic, hypotonic) and the one with lower solutes is called (isotonic, hypertonic, hypotonic)

c. Water will diffuse (down/against) its concentration gradient, from the side where water is (more/less) concentrated to the side where water is (more/less) . That is, water always goes from (hypertonic/hypotonic) to (hypertonic/hypotonic).

7. In the diagrams of red blood cells and plant cells, label above each solution as being ISO-, HYPER- or HYPO- tonic.

a. In figure 1, the animal cell is bursting. This is called

__________________

b. in figure 1, the plant cell is swollen from pressure in the central vacuole. This is called ________________

c. In figure 3, the cytoplasm of both plant and animal cells has shrunk. This is called ______________________

d. In figure 3, why does the plant cell cytoplasm shrink but not the cell wall? ______________________________________

8. The roots of a plant have root hair cells that absorb water from the soil. The diagram below shows two different kinds of roots. The concentration of the solution inside the cell is higher than the concentration of the solution in the soil.

a) Explain why water moves from the soil into the root hair cell.

b) Suggest why root hair cells are long and thin and not short and stubby?

9. Strawberry jelly is a very strong solution of sugar. By contrast, the cytoplasm in a bacterium is a much weaker solution. soltusolution.

Weaker solution. The cell wall of a microbe is made up of a semi-permeable membrane.

a. Would water flow from the microbe to the jam, or from the jam to the microbe by osmosis?

b. Explain why bacteria find it difficult to survive in jam.

-----------------------

B

A

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download