Active Transport Against the Gradient · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Pumping uphill with energy

Science · Organisms & Life Processes · ages 14-15
Name ______________________   Date ____________

  1. Where does the energy for active transport come from?

    • Sunlight on the leaf
    • ATP from respiration
    • Heat from the surroundings

  2. Which direction marks active transport?

    • Low concentration to high concentration
    • High concentration to low concentration
    • Equal concentrations both ways

  3. Osmosis moves water without spending energy.

    Circle one:   True   False

  4. A root is poisoned so it cannot respire. What happens?

    • Both mineral and water uptake stop
    • Mineral uptake stops but water still enters
    • Water uptake stops but minerals still enter

  5. Gut lining cells absorb lots of glucose uphill. What would you expect inside them?

    • Many mitochondria
    • No mitochondria
    • Many chloroplasts

  6. What does the sodium potassium pump do?

    • Lets both ions drift downhill for free
    • Pushes potassium out and pulls sodium in using ATP
    • Pushes sodium out and pulls potassium in using ATP

  7. If cutting the energy supply stops a movement, the movement was passive.

    Circle one:   True   False

  8. Ana sees glucose move from gut food, where it is scarce, into blood, where it is plenty, and calls it diffusion. What is wrong?

    • Nothing, she is right
    • It is active transport, moving up the gradient
    • It is osmosis, since glucose dissolves
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Pumping uphill with energy W1-mt_BQf1bgo9oM-s1

  1. ATP from respiration · The cell spends ATP, released in respiration, to pump substances uphill.
  2. Low concentration to high concentration · Active transport runs uphill, from low concentration to high concentration.
  3. True · Osmosis runs downhill like diffusion, so it costs the cell nothing.
  4. Mineral uptake stops but water still enters · Minerals need ATP from respiration, while water enters by free osmosis.
  5. Many mitochondria · Heavy pumping needs lots of ATP, so pumping cells are packed with mitochondria.
  6. Pushes sodium out and pulls potassium in using ATP · It spends ATP to move both ions against their gradients: sodium out, potassium in.
  7. False · Stopping without energy marks active transport. Passive movement carries on for free.
  8. It is active transport, moving up the gradient · Scarce to plenty is uphill, so the movement must be active transport.
Worksheet · LightMySky