AKS REVIEW

1
AKS REVIEW

• Cell Transport

1. DEFINE HOMEOSTASIS

• Pg. GL 11 (HONORS)
• Pg. 1080 (CP)
• 2. Give an example of a homeostatic mechanism in
  a uni-
• cellular organism. Explain how it works.
• See pg. 523(Honors) See Contractile Vacuole
• B. See pg. 499 (CP) See Paramecium (one-celled
  organism)

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Cell transport

• 2A. Contractile vacuoles are cavities in
  paramecium that collect water. When full it
  contracts (squeezes itself) and pumps the water
  out.
• If a parmecium was living in a hypotonic
  environment (low solute/hi water conc)
• what would you expect to occur?

3
Cell Transport

• 3. Give an example of a homeostatic mechanism in
  a multicellular organism.
• A. Perspiration is the bodys way of cooling
  itself. Dogs dont sweat so as they get
  overheated, they pant more, releasing body heat.
  This keeps their body temp in balance
  (homeostasis)

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Cell Transport

• 4. Diffusion and Osmosis. See Q.8 on AKS review
  for Biochemistry
• Activity Fill out worksheet

5
Cell Transport
5A.

• Active Transport
• -a way of moving materials across the cell
  membrane (uphill) from an area of low to
• high concentration. REQUIRES ENERGY!
• (and a protein channel)
• Ex. Sodium-potassium pump

(Honors text ref pg. p. 205) (CP text ref
pg.189)
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Cell Transport

• Passive transport is simply how diffusion and
  osmosis work. Requires NO ENERGY
• as materials naturally move (downhill) from an
  area of high to low concentration.
• Ex. Glucose moving into cells from bloodstream
  after you eat ice cream.

7
Cell Transport

• 7. Identify factors that affect the rate (speed)
  of cellular transport
• Answer
• Concentration-the more there is of a substance on
  either side of a cell membrane, the faster it
  will diffuse into or out of a cell. The hill or
  concentration gradient is steeper. Will a ball
  roll FASTER down a steep hill? Of course!
• Temperature the higher the temp., the faster
  molecules move. The faster they move, the quicker
  they will diffuse into/out of cell.

8
Cell Transport

• 9. Exocytosis-the removal of large amounts of
  material from a cell (Exo means out)
• Endocytosis-the taking in of large amounts of
  material by a cell (Endo in)
• Note This is how your white blood cells kill
  bacteria and viruses in your body. They swallow
  them and destroy them.