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?

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

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

   • Oxygen is made inside the cells
   • The cells pull oxygen in with energy
   • Using it keeps the inside count low
   • 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
   • Dynamic equilibrium
   • A frozen state
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
   • Both at the same speed
   • The cold water
   • Neither: coloring can't spread
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 A
   • Cell B
   • 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 reverses direction
   • It speeds up
   • It slows down
   • It jumps to a stop
8. 8.

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

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

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

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

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

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