Active transport: pumps and vesicles

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Membrane drawing (model, not to scale). Ari studies a membrane drawing. Letter A points to a large protein that spans the bilayer, with an ATP label beside it. What is A?

   • A phospholipid head, which faces the watery fluid
   • A pump, which uses ATP energy to move ions
   • A pump, which moves ions down the gradient with no energy
   • A channel protein, which opens a tunnel and uses no ATP
2. 2.

   On Bo’s drawing, letter D points to a small bubble of membrane inside the cell. It just pinched off from the membrane and holds a large particle. What is D?

   • A vesicle made by exocytosis
   • A channel protein with a tunnel
   • A pump that moves ions using ATP
   • A vesicle made by endocytosis
3. 3.

   Esme studies another membrane drawing. Letter B points to a protein with a tunnel through it and no ATP label beside it. What is B?

   • A pump, which moves ions toward the side with more
   • A channel protein, which uses ATP to open its tunnel
   • A vesicle, which carries particles into the cell
   • A channel protein, which lets ions through with no ATP
4. 4.

   Two membrane drawings (model, not to scale). Jun compares two drawings of sodium ions crossing a membrane. Which drawing shows active transport, and why?

   • Drawing Y, because ions are moved by a channel using ATP
   • Drawing X, because ions are moved to the side with more ions
   • Drawing Y, because ions are moved to the side with fewer ions
   • Drawing X, because ions are moved with no energy from the cell
5. 5.

   Membrane drawing (model, not to scale). Milo reads a membrane drawing with a pump and an ATP label. Which meaning matches the term active transport?

   • Moving a substance across a membrane from high to low concentration
   • Moving a substance across a membrane with no energy from the cell
   • Moving a substance across a membrane using the cell’s energy
   • Moving a substance across a membrane through any channel protein
6. 6.

   Noah reads about sodium ions on two sides of a membrane. Which meaning matches the term electrochemical gradient?

   • The energy a pump gets when it splits an ATP molecule
   • The path an ion takes through a channel protein
   • A concentration difference and a charge difference acting together on an ion
   • A concentration difference with no charge difference involved

7. 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. Inside the cell, a bubble of membrane touches the bottom row and opens to the outside; 4 molecules inside the bubble move to the outside.

8. 7.

   Pia sees a vesicle touching a membrane in a drawing. Which meaning matches the term exocytosis?

   • A particle slips through the bilayer toward the side with less
   • A vesicle fuses with the membrane and releases its contents outside
   • The membrane folds inward and pinches off a vesicle holding a particle
   • A pump moves sodium ions out of the cell using ATP

9. 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 pump with 1 ATP label beside it. Arrows show 3 sodium ions moving from inside to outside and 2 potassium ions moving from outside to inside in one cycle.

10. 8.

    In Ren’s drawing, what does pump P move in one cycle?

    • 2 sodium ions out and 3 potassium ions in
    • 3 sodium ions in and 2 potassium ions out
    • 3 sodium ions out and 2 potassium ions in
    • 3 sodium ions out and 3 potassium ions in
11. 9.

    Membrane drawing (model, not to scale). Inside the cell: 14 potassium ions. In Tala’s drawing, pump P moves potassium ions into the cell. Which description fits this move?

    • Toward the side with fewer ions, which takes no energy
    • Toward the side with fewer ions, which takes ATP
    • Toward the side with more ions, which takes no energy
    • Toward the side with more ions, which takes ATP

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. Letter A points to a protein with a tunnel through it and no label beside it. Letter B points to a protein with an ATP label beside its inside end. Outside the cell: 6 sodium ions. Inside the cell: 6 sodium ions.

13. 10.

    In Zee’s drawing, which lettered protein has an ATP label beside it?

    • Neither, since ATP labels sit in the watery fluid
    • A, the protein with the tunnel and no label
    • Both A and B, since membrane proteins use ATP
    • B, the protein with the label beside it