Memory Anchor:

• Diffusion occurs through the cell membrane, because there are small gaps in the me.

Super Challenge:

Stretch:

Challenge:

Key Questions:

1. Describe what particles do in a fluid.
   • Particles in a fluid are always moving.
2. What is diffusion?
   • Diffusion is the movement of a substance from a region of higher concentration to a region of lower concentration.
3. What is concentration?
   • Concentration is the number of a particular type of Particle in a volume of space.
4. How do the random movement of particles result in the movement from a higher concentration to a lower concentration?
   • Half of a large number is more than half of a smaller number. So more Particles will travel from a larger number of Particles (high concentration), than are replaced by the smaller number moving form the smaller number of Particles (lower concentration).
5. Under what conditions does diffusion happen faster?
   • Diffusion happens fastest when: - there is a large surface area - there is a short distance between areas of differing concentration. - at higher temperatures.
6. Why does glucose diffuse into muscle cells from the blood?
   • Glucose diffuses into a muscle Cell, because there is a higher concentration of glucose Particles in the blood than the Cell.
7. Why does oxygen diffuse into muscle cells from the blood?
   • Oxygen diffuses into a muscle Cell, because there is a higher concentration of oxygen Particles in the blood than the Cell.
8. Why does carbon dioxide diffuse out of muscle cells into the blood?
   • Carbon dioxide diffuses out of a muscle Cell, because there is a higher concentration of Carbon dioxide Particles in the Cell than the blood.
9. Why does water diffuse out of muscle cells into the blood?
   • Water diffuses out a muscle Cell, because there is a higher concentration of oxygen Particles in the blood than the Cell.
10. How can diffusion occur in and out of cells.
    • Diffusion occurs through the Cell membrane, because there are small gaps in the membrane.
11. What does partially-permeable mean?
    • Partially-permeable allows certain Particles through but not others.permeable..
12. Why is the cell membrane referred to as partially-permeable?
    • The small gaps allow smaller molecules through but not larger ones. This means the membrane is partially-