Active transport: pumps and vesicles

Grade 9 Science Worksheet

Circle the best answer.

1. Read this first

   Use this

   Membrane drawing (model, not to scale). A bilayer: a top row of round heads, tails meeting in the middle, and a bottom row of round heads, with watery fluid outside the cell above and watery fluid inside the cell below. Letter P points to a sodium-potassium pump across the bilayer, with 1 ATP label beside it. A note says the pump runs 4 cycles and uses 1 ATP in each cycle.

2. 1.

   Ari’s drawing shows a sodium-potassium pump that runs 4 cycles and uses 1 ATP in each cycle. How many ATP are used, and how many ions move?

   • 4 ATP used, 12 sodium ions out, 12 potassium ions in
   • 4 ATP used, 8 sodium ions out, 12 potassium ions in
   • 12 ATP used, 12 sodium ions out, 8 potassium ions in
   • 4 ATP used, 12 sodium ions out, 8 potassium ions in
3. 2.

   A sodium-potassium pump in Bo’s drawing has moved 12 potassium ions into the cell, using 1 ATP per cycle. How many sodium ions has it moved out, and how many ATP has it used?

   • 8 sodium ions out, using 4 ATP
   • 18 sodium ions out, using 12 ATP
   • 18 sodium ions out, using 6 ATP
   • 12 sodium ions out, using 6 ATP

4. Use the table

   Lab card (model data), not to scale. Counts before the sodium-potassium pump P, which sits in a bilayer, runs.

   Ion	Outside the cell	Inside the cell
   sodium ions	40	15
   potassium ions	10	30

   A note says pump P then runs 3 cycles. The card is read about only: a teacher counted the ions, and no one handled anything.

5. 3.

   Esme reads the counts before a pump runs 3 cycles. What are the counts after the 3 cycles?

   • Sodium: 31 outside, 24 inside; potassium: 16 outside, 24 inside
   • Sodium: 46 outside, 9 inside; potassium: 1 outside, 39 inside
   • Sodium: 49 outside, 6 inside; potassium: 4 outside, 36 inside
   • Sodium: 43 outside, 12 inside; potassium: 7 outside, 33 inside
6. 4.

   Jun watches potassium ions move through protein P from outside (4 ions) to inside (20 ions), with an ATP label beside P. What kind of transport is this?

   • Primary active transport, because the ions move down their gradient
   • Facilitated diffusion, because a protein helps the ions cross
   • Primary active transport, because ATP powers the protein directly
   • Secondary active transport, because the gradient does the work

7. Use this

   Membrane drawing (model, not to scale). A bilayer: a top row of round heads, tails meeting in the middle, and a bottom row of round heads, with watery fluid outside the cell above and watery fluid inside the cell below. Letter G points to a protein across the bilayer that carries sodium ions and glucose molecules into the cell together; no ATP label is beside G. Outside the cell: 50 sodium ions and 6 glucose molecules. Inside the cell: 10 sodium ions and 30 glucose molecules.

8. 5.

   Kira’s drawing shows protein G moving glucose into a cell that already holds more glucose than the outside. What kind of transport is this?

   • Facilitated diffusion, because a protein carries glucose across
   • Primary active transport, because proteins that move glucose use ATP directly
   • Secondary active transport, because glucose moves down its gradient
   • Secondary active transport, because the sodium gradient supplies the energy

9. Use this

   Membrane drawing (model, not to scale).

10. 6.

    Luz’s drawing shows carrier H moving glucose from outside (30 molecules) to inside (10 molecules), with no ATP label. What kind of transport is this?

    • Primary active transport, because a carrier protein is used
    • Secondary active transport, because the carrier changes shape
    • Primary active transport, because glucose moves down its gradient
    • Facilitated diffusion, because glucose moves down its gradient with no ATP
11. 7.

    Receptor proteins on Noah’s cell membrane bind one kind of substance, and the membrane pinches in around it. Which process is this?

    • Phagocytosis, which engulfs a large particle of any kind
    • Pinocytosis, which takes in a drop of fluid
    • Receptor-mediated endocytosis, which takes in one specific substance
    • Exocytosis, which takes in one specific substance

12. Use this

    Membrane drawing (model, not to scale). A bilayer: a top row of round heads, tails meeting in the middle, and a bottom row of round heads, with watery fluid outside the cell above and watery fluid inside the cell below. A gland cell packaged an enzyme in a secretory vesicle at the Golgi apparatus. Letter V points to the vesicle, which fuses with the bottom row and releases 5 enzyme molecules to the outside of the cell.

13. 8.

    A gland cell in Pia’s drawing has a vesicle from the Golgi apparatus that fuses with the plasma membrane and releases an enzyme outside. Which process is this?

    • Endocytosis, which releases the contents outside
    • Phagocytosis, which engulfs a large particle
    • Pinocytosis, which takes in a drop of fluid
    • Exocytosis, which releases the contents outside

14. Use this

    Membrane drawing (model, not to scale). A bilayer: a top row of round heads, tails meeting in the middle, and a bottom row of round heads, with watery fluid outside the cell above and watery fluid inside the cell below. Letter P points to a sodium-potassium pump that faces the inside of the cell. 3 sodium ions are attached to it, 1 ATP has been split, and a phosphate group is attached to P. Outside the cell: 2 potassium ions.

15. 9.

    Ren’s drawing shows a sodium-potassium pump after ATP has been split. What does the pump do next?

    • It changes shape to face the outside and binds 3 potassium ions
    • It stays facing the inside while the sodium ions slip out
    • It changes shape to face the outside and lets go of the 3 sodium ions
    • It lets go of the 3 sodium ions inside the cell and takes up more

16. Use this

    Membrane drawing (model, not to scale). A bilayer: a top row of round heads, tails meeting in the middle, and a bottom row of round heads, with watery fluid outside the cell above and watery fluid inside the cell below. Letter G points to a protein across the bilayer that carries sodium ions and glucose molecules into the cell together; no ATP label is beside G. Outside the cell: 60 sodium ions and 10 glucose molecules. Inside the cell: 8 sodium ions and 25 glucose molecules.

17. 10.

    Zee’s drawing shows protein G open, with sodium ions and glucose outside. Predict what happens to the glucose molecules at G.

    • They keep moving in, carried by sodium ions moving down their gradient
    • They stop, since glucose would have to move toward more glucose
    • They move in, and G uses ATP directly to carry them
    • They move in with no energy source, since carriers use no energy