Memory Anchor:

• Super Challenge:

  Stretch:

  Challenge:

Key Questions:

1. What is the name of the process in which water moves across cell membranes?
   • Osmosis
2. What is the surface area to volume ratio of a single-celled organism like?
   • A single-Celled organism has a relatively large surface area to volume ratio.
3. How does having a large surface area to volume ratio help cells?
   • Having a large surface area to volume allows sufficient transport of molecules into and out of the Cell to meet the needs of the organism.
4. How do you calculate surface area to volume ratios?
   • volume = width x height x bredth area = width x height display as a ratio
5. Why do simple organisms need exchange surfaces?
   • To allow for diffuse of substances in and out. They have high surface area to volume ratio to increase the rate of this.
6. Why do multicelluar organisms need transport systems?
   • Too complex for simple diffusion across a membrane so transport systems are needed to deliver substances to target organs/tissues.
7. How are the small intestine and lungs in mammals adapted for exchanging materials?
   • Lungs have a large surface area to volume ratio due to the structure of alveloi Small intestines have villi to increase their surface to volume ratio
8. How are the gills in fish are adapted for exchanging materials?
   • Gills have a large surface area, partially permable membrane.
9. How are leaves in plants adapted for exchanging materials?
   • Leaves have guard Cells and spongy mesophyl with gaps
10. How are multicellular organisms adapted for exchanging materials?
    • MultiCellular organisms have specalised surfaces and organ systems
11. How do organisms get substances they need in and out of cells?
    • Specalised surfaces allow sufficient molecules to be transported into and out of Cells for the organism?s needs.
12. How can the effectiveness of an exchange surface be increased?
    • The effectiveness of an exchange surface is increased by: ? having a large surface area ? a membrane that is thin, to provide a short diffusion path ? (in animals) having an efficient blood supply ? (in animals, for gaseous exchange) being ventilated.