A. Use the words below to complete the sentences. Vocabulary
A selectively permeable membrane, Diffusion, Concentration, Osmosis

1) refers to the amount of a substance in a given space.

2) is the movement of particles from an area of higher concentration

to an area of lower concentration.

3) allows some materials to pass through it but keeps other

materials out.

4) is the diffusion of water molecules through a selectively

permeable membrane.

5) moves wastes from inside a cell to outside a cell.

6) can be compared to a window screen.

7) happens when water particles move from a place where their

concentration is higher to a place where their concentration is lower.

8) is the process by which oxygen is moved into and carbon dioxide

is moved into a cell.

Use the following diagram to answer questions 9 to 11

9) In which diagram(s) does water move into and out of the cell at the same rate?

10) In which diagrams(s) will the cell begin to swell?

11) Which diagram(s) shows what would happen if a cell were placed in salt water? ___

B. State whether each statement is true or false.

1. All living things have a specialized mechanism to exchange substances with their

environment.

2. Osmosis involves the movement of solute molecules.

3. The cell membrane is a selectively permeable membrane.

4. Chemicals in the air diffuse until evenly distributed.

5. A concentration gradient occurs when particles are evenly distributed in a region.

6. Diffusion occurs in the lung at the site of gas exchange in the alveoli.

7. Plants obtain carbon dioxide for photosynthesis through their roots.

8. A small surface area increases the rate of diffusion.

9. The tonicity is the comparative differences between the concentration of two solutions.

10. Red blood cells fight against infections caused by pathogens in the body.