Diffusion across a cell membrane

Grade 7 Science Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   Use this

   Cell arrow diagram (model data, not to scale). No arrows are drawn yet.

2. 1.

   Which side of the membrane has the higher concentration of oxygen, Ari?

   • Outside the cell
   • The two sides are even
   • The membrane itself
   • Inside the cell
3. 2.

   Which side of the membrane has the higher concentration of carbon dioxide, Bo?

   • Neither side has any
   • The two sides are even
   • Outside the cell
   • Inside the cell
4. 3.

   Which side of the membrane has the higher concentration of oxygen now, Esme?

   • The membrane holds the most
   • Neither: the sides are even
   • Inside the cell
   • Outside the cell
5. 4.

   Which way will oxygen move across the membrane, Jun?

   • It won't cross the membrane
   • Into the membrane, where it stays
   • Out of the cell
   • Into the cell
6. 5.

   Which way will carbon dioxide move across the membrane, Kira?

   • Into the cell
   • Out of the cell
   • It stays where it is
   • Into the nucleus

7. Use this

   Leaf cell arrow diagram (model data, not to scale). Boxes: air space in the leaf, with 2 oxygen dots; inside the leaf cell, with 9 oxygen dots. The cell membrane is between them, and both boxes are the same size. No arrows are drawn yet.

8. 6.

   In sunlight, a leaf cell makes oxygen. Which way will that oxygen move, Luz?

   • Out into the air space
   • Nowhere: leaves keep their oxygen
   • Into the leaf cell
   • Down into the roots
9. 7.

   Milo reads the word diffusion in a science book. What does it mean?

   • Particles turning into new ones
   • Particles spreading from more crowded to less crowded
   • Particles being pumped by the cell
   • Particles gathering where they are already crowded
10. 8.

    Noah reads that particles move down their concentration gradient. Which way is that?

    • From higher to lower concentration
    • From the top of the cell to the bottom
    • From lower to higher concentration
    • Toward the membrane
11. 9.

    Does a cell spend energy to move oxygen in by diffusion, Ren?

    • Yes: the cell pumps it in
    • No: diffusion needs no energy from the cell
    • Yes: the membrane pulls it in
    • No: oxygen stays outside
12. 10.

    Why do particles spread out across a membrane on their own, Tala?

    • They keep moving at random
    • Empty space pulls them
    • The cell pushes them along
    • Gravity drops them through