1. What key role does diffusion play?
    It limits the size of most cells 

    **importance of surface to volume ratio
  2. Does body size have a strong influence on how animals work?

    **importance of surface to volume ratio
  3. What is homeostasis?
    • maintaning a relatively constant internal environment
    • *importance of negative feedback
  4. How do cells exchange gases and other molecules with environment?
    by diffusion
  5. (diffusion) What happens as cell get larger..
    • the time for molecules to diffuse from one end of a cell to another becomes significantly longer
    • *does not occur linearly
  6. Image Upload 1what does distance mean?
    -distance traveled by the diffusing solute along one axis after time t
  7. Image Upload 2What does time mean?
    the time since diffusion began
  8. Image Upload 3 What does diffusion coefficient mean?
    diffusion coefficient of a solute in free solution
  9. characteristics of formula of approximation of time of diffusion (4)
    -determines time it takes solute to diffuse a given distance in a medium

    -smaller the number, slower the movement

    -determined by physical characteristics of the solute and the medium

    -inversely related to the molecular weight of solute
  10. What limits the sizes of cells in mammalian systems?
    the surface area to volume issues
  11. What are potential problems for a large organism?
    -cant get rid of heat fast enough

    -cant get rid of waste products fast enough

    -cant get food in fast enough
  12. AS the surface area and volume got larger...
    the surface area to volume ratio got smaller
  13. Does a small cell have a large or small surface area to volume ratio?
  14. Why does volume increases faster than surface area?
    volume is in cubic function
  15. What metric is volume measured in?
    cubic function
  16. what metric is surface area measured in?
  17. For cells,
    the amount of stuff on the inside of the cell increases far faster than the door to get things in and out of the cell
  18. If there were no biological compensatory mechanisms, as a spherical animal became larger, its surface area would increase in proportion to...
    volume 2/3
  19. What is surface area proportional to?
    it is proportional to (length)2
  20. What is volume proportional to?
  21. what is surface area proportional to?
  22. What does the apical surface of epithelium do?
    faces internal or external environment
  23. What does the basolateral surface of epithelium do?
    connects to other tissues
  24. 3 characteristics that indicate the structure is used to increase surface area
    • -folded surfaces with projections
    • *lining of small intestine

    • -flattened structures
    • *fish gills

    • -highly branched structures
    • *capillaries
  25. 3 important set ups for the experiment to measure what method dominates in a salmon
    -placed salmon in the middle

    -on left side it measured the oxygen uptake from the skin

    -on right side it measured the oxygen uptake of the gills
  26. COnclusion of the salmon experiment (2)
    -in the beginning, the oxygen uptake is higher through the skin

    -as the salmon gets older, oxygen uptake is higher through the gills
  27. Why do salmons use their gills more than when they are older than skin?
    Their surface area increases so they need a more efficient way to process gas exchanges
  28. Who has a higher metabolic rate, large or small organisms?
    smaller organisms because smaller organisms lose heat quicker so to combat this issue it produces more heat inside
Card Set
diffusion and surface area