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Flashcards · Biology · Transport in Cells

Active Transport

24 cards

  1. What is active transport?

    The movement of substances from a more dilute to a more concentrated solution, against a concentration gradient, using energy from respiration.

  2. What does active transport need?

    Energy from respiration.

  3. Does active transport move substances up or down the concentration gradient?

    Up it: from low concentration to high concentration.

  4. Which sub-cellular structures release the energy for active transport?

    Mitochondria.

  5. Why do cells that do a lot of active transport have many mitochondria?

    They release the energy from respiration that active transport needs.

  6. What is a carrier protein?

    A protein in the cell membrane that picks up a particular substance and moves it across.

  7. Give an example of active transport in plants.

    Mineral ions being taken into root hair cells from the dilute soil solution.

  8. Why do plants need mineral ions?

    For healthy growth. For example nitrate for proteins and magnesium for chlorophyll.

  9. Why can't root hair cells take up ions by diffusion?

    The ions are at a lower concentration in the soil than in the cell.

  10. Give an example of active transport in animals.

    Sugar being absorbed from the gut into the blood.

  11. Why is active transport needed to absorb sugar from the gut?

    Sometimes the concentration of sugar in the gut is lower than in the blood.

  12. Why must the body absorb sugar?

    Sugar molecules are used for cell respiration.

  13. What happens to active transport if a cell stops respiring?

    It stops, because there is no energy.

  14. Why does waterlogged soil reduce ion uptake?

    Less oxygen means less respiration, so less energy for active transport.

  15. How does active transport differ from diffusion?

    It goes against the concentration gradient and needs energy. Diffusion goes down the gradient and needs none.

  16. Which processes need no energy from the cell?

    Diffusion and osmosis.

  17. Which process moves only water?

    Osmosis.

  18. What does "against the concentration gradient" mean?

    From a lower concentration to a higher concentration.

  19. What is the usual mistake about active transport?

    Saying it is the same as diffusion, or forgetting that it needs energy.

  20. Is a ball rolling uphill a good picture of diffusion or active transport?

    Active transport: it takes energy to push it up.

  21. Active transport across a cell membrane with a marker X on the carrier protein. What is the structure marked X, and what does it do?

    A carrier protein. It picks up a substance and moves it across the cell membrane, against the concentration gradient, using energy from respiration.

  22. Active transport across a membrane with nothing labelled. Label this diagram of active transport and say what the mitochondrion is for. The same diagram with the lower and higher concentrations, the carrier protein and the energy from respiration labelled.

  23. Three pictures with no labels: a ball rolling downhill, water crossing a membrane, and a ball pushed uphill. Name each process and say which needs energy. The three transport processes named and described, with active transport the only one needing energy.

  24. Root hair cell and gut examples of active transport. Why can't a root hair cell take in mineral ions by diffusion?

    The mineral ions are at a lower concentration in the soil than in the root hair cell, so they would diffuse out. Active transport moves them in against the gradient, using energy from respiration.