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

   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 channel protein, which lets ions through with no ATP
   • A vesicle, which carries particles into the cell
3. 3.

   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 X, because ions are moved with no energy from the cell
   • 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
4. 4.

   Kira compares two drawings of a membrane and a large particle. Which drawing shows endocytosis, and why?

   • Drawing X, because the cell sends a particle out
   • Drawing X, because the cell takes a particle in
   • Drawing Y, because the cell takes a particle in
   • Drawing Y, because the cell sends a particle out
5. 5.

   Luz compares two drawings of one cycle of a sodium-potassium pump. Which drawing is correct?

   • Drawing X, because 3 sodium ions leave for 2 potassium ions that enter
   • Drawing Y, because the pump needs no ATP to move the ions
   • Drawing X, because the same number of ions go each way
   • Drawing Y, because 3 potassium ions enter for 2 sodium ions that leave
6. 6.

   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 using the cell’s energy
   • Moving a substance across a membrane through any channel protein
   • Moving a substance across a membrane with no energy from the cell
7. 7.

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

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

8. 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.

9. 8.

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

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

10. 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.

11. 9.

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

    • 2 sodium ions out and 3 potassium ions in
    • 3 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
12. 10.

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