Chapter 4 ≠ WHAT DO YOU KNOW?†††††††††††††††† † † Name ____________________

1.† One way cells maintain homeostasis is by controlling the movement of substances across the [ cell membrane / cytoplasm ].

2.† Movement across the cell membrane that does not require energy is called [ active / passive ] transport.

3.† The difference in the concentration of a substance across a space is called a concentration [ equilibrium / gradient ].

4.† If there is a concentration gradient, substances will move from an area of high concentration to an area of [ equal / low ] concentration.

5.† The cell membrane is [ selectively permeable / impermeable ].

6.† [ Equilibrium / Diffusion ] is the simplest type of passive transport.

7.† The diffusion of water through a selectively permeable membrane is called [ osmosis / diffusion ].

8.† The direction of water movement across the cell membrane depends on the concentration of free water [ molecules / solutions ].

9. A solution that causes a cell to swell is called a [ hypertonic / hypotonic ] solution.

10.† Organelles that collect excess water inside the cell and force water out are called [ diffusion organelles / contractile vacuoles ]

11.† Transport proteins provide passageways for molecules to move across the [ vacuole / cell membrane ]

12.† In some ion channels, pores can be closed by an ion channel [ gate / membrane ]

13.† In diffusion, molecules [ spread out / condense ]

14.† [ Carrier / Facilitated ] proteins are used to transport specific substances across the cell membrane.

15.† Facilitated diffusion moves substances down their concentration gradient [ with / without ] using the cellís energy.†