Diffusion across a cell membrane

Grade 7 Science Worksheet

Circle the best answer.

1. 1.

   Cell arrow diagram (model data, not to scale). No arrows are drawn yet. Which way does each gas move across this membrane, Ari?

   • Oxygen out, carbon dioxide in
   • Both gases move out
   • Both gases move in
   • Oxygen in, carbon dioxide out
2. 2.

   model data, not to scale. A leaf cell in sunlight uses carbon dioxide and makes oxygen. Which way does each gas move, Bo?

   • Oxygen in, carbon dioxide out
   • Carbon dioxide in, oxygen out
   • Neither moves in sunlight
   • Both gases move in
3. 3.

   During a run, Esme's muscle cells use oxygen quickly to release energy from food. Why does oxygen keep moving into them?

   • The cells pull oxygen in with energy
   • Using it keeps the inside count low
   • Oxygen is made inside the cells
   • The cells pump carbon dioxide in
4. 4.

   Particles still move, but the counts on each side stay even. What do scientists call this state, Luz?

   • A steep concentration gradient
   • Active transport
   • A frozen state
   • Dynamic equilibrium
5. 5.

   A teacher drops food coloring into a glass of warm water and a glass of cold water. In which does it spread faster, Milo?

   • The warm water
   • Neither: coloring can't spread
   • The cold water
   • Both at the same speed
6. 6.

   Cell A has 20 oxygen dots outside and 2 inside. Cell B has 8 outside and 6 inside. Into which cell does oxygen move faster, Noah?

   • Cell B
   • Cell A
   • Both at the same speed
   • Neither: oxygen stays out
7. 7.

   As the two sides get closer to even, what happens to the speed of diffusion, Pia?

   • It jumps to a stop
   • It speeds up
   • It slows down
   • It reverses direction
8. 8.

   Why is oxygen usually lower inside a body cell than outside it, Ren?

   • Oxygen is made outside cells
   • It uses oxygen to release energy
   • The cell pushes its oxygen back outside
   • The membrane keeps oxygen out
9. 9.

   Body cells make carbon dioxide as they release energy from food. Which way does that carbon dioxide move, Tala?

   • Out of the cell
   • It stays inside the cell
   • Into the nucleus
   • Into the cell from outside
10. 10.

    Zee draws an arrow for carbon dioxide from 2 dots outside a cell to 9 dots inside. What is wrong with it?

    • Nothing: gases move toward more
    • It should be a circle
    • Carbon dioxide can't cross
    • It should point out, from 9 to 2