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Module 7 Lesson 3 Progress Check

Prompt

Read pgs. 173-180. Then answer the "Check Your Progress" questions (p180 #1, 2, 3, 4, 5) and submit your answers here.

Response

  1. List and describe the types of cellular transport.

    • Passive Transport: Moves substances without energy along a concentration gradient and includes diffusion, facilitated diffusion, and osmosis.
    • Active Transport: Requires energy to move substances against a concentration gradient, involving pumps and cotransporters.
    • Bulk Transport: Engages in the energy-dependent process of moving large quantities or large particles into (endocytosis) and out of (exocytosis) the cell via vesicles.

  2. Explain the role of the cell membrane during passive transport and active transport

    During passive transport, the cell membrane facilitates the movement of molecules without energy, letting them flow from higher to lower concentration areas. In active transport, the membrane uses energy to move substances from areas of lower to higher concentration, often involving protein pumps and vesicles.

  3. Sketch a before and an after diagram of an animal cell placed in a hypertonic solution.

    Hypertonic Diagram

    Before being placed in a hypertonic solution, an animal cell will be normal in size with water balanced between inside and outside. After exposure to a hypertonic solution, water will leave the cell, causing it to shrink and the cell membrane to crinkle or collapse inward due to water loss.

  4. Contrast how facilitated diffusion is different from active transport.

    Facilitated diffusion differs from active transport as it allows substances to move across the cell membrane down their concentration gradient through specific channels or carriers without energy. Active transport, on the other hand, requires energy to move substances against their concentration gradient, often through protein pumps.

  5. Describe Some organisms that normally live in pond water contain water pumps. These pumps continually pump water out of the cell. Describe a scenario that might reverse the action of the pump.

    In a hypotonic environment, where the outside solution is less concentrated than the cell's interior, water pumps usually expel water to prevent swelling. However, if the external solution became hypertonic, water would naturally move out, potentially reducing the need for the pumps to actively remove water.