Read 222-224 and answer the following in your journal in complete sentences.
1. Define diffusion. Movement of molecules from area of greater concentration to area of
lesser concentration
2. Define gradient. molecule is more concentrated in one area than another, often
concentration changes gradually from most concentrated to least
3. What makes diffusion happen? happens through random movement of molecules, no
energy required, molecules always moving toward chaos (less ordered arrangement)
4. What would you need to use to fight diffusion? energy
5. In what states of matter (solid, liquid, gas) can diffusion happen? all
6. When does diffusion stop? When concentration everywhere is same (evenly distributed)
7. What 2 things affect the movement of molecules across a membrane? Concentration of
that molecule inside and outside the membrane, also whether the membrane has carrier or
channel for that molecule
8. What is osmosis? Movement of water from area of higher concentration of water (less
solute) to area of lesser concentration of water (more solute dissolved)
9. What is osmotic pressure? Pressure inside cell from water moving in through osmosis
10. How does a vacuole affect plant structure? Swells with water and puts pressure on
everything in cell, pushes membrane against cell wall, keeps plants from wilting
11. What molecules cannot move across a membrane? Large ones, charged ones
12. What is passive transport and how is it different from ordinary diffusion? Requires
protein carrier or channel, but molecules move from greater to lesser concentration
13. What is active transport and why is it necessary? Molecules move against gradient (from
area of lesser concentration to area of greater), requires energy and transport proteins
Solution – mixture of solid(s), liquid(s) and/or gas(es), uniformly mixed; like salt water
Solute – dissolved substance (like salt in salt water)
Solvent – what substance is dissolved in; water in salt water
Isotonic solution– concentration of dissolved solutes outside cell equals concentration of solutes
inside
Hypertonic solution -- concentration of dissolved solutes outside cell is greater than
concentration of solutes inside
Hypotonic solution -- concentration of dissolved solutes outside cell is less than concentration of
solutes inside