Diffusion across a cell membrane

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   Cell arrow diagram (model data, not to scale). No arrows are drawn yet. Dots can cross both ways. When the two sides even out, how many oxygen dots will each side have, Ari?

   • 7 on each side
   • 8 on each side
   • 0 outside and 16 inside
   • 12 on each side
2. 2.

   model data, not to scale. Dots can cross both ways. When the two sides even out, how many oxygen dots will each side have, Bo?

   • 14 on each side
   • 9 on each side
   • 0 outside and 22 inside
   • 11 on each side
3. 3.

   Cell arrow diagram (model data, not to scale). No arrows are drawn yet. Dots can cross both ways. When the two sides even out, how many carbon dioxide dots will each side have, Esme?

   • 16 on each side
   • 0 inside and 24 outside
   • 12 on each side
   • 10 on each side
4. 4.

   Outside a cell, oxygen stays at 10 dots. The cell starts using oxygen faster, and its inside count drops from 4 to 1. What happens next, Jun?

   • Oxygen stops moving in
   • Oxygen moves in faster
   • The cell must push it in
   • Oxygen starts moving out
5. 5.

   model data, not to scale. No arrows are drawn yet. At night a leaf cell makes no sugar but keeps using oxygen to release energy. Which way does each gas move, Kira?

   • Oxygen in, carbon dioxide out
   • Neither moves at night
   • Both gases move out
   • Oxygen out, carbon dioxide in

6. Read this first

   Use this

   Cell arrow diagram (model data, not to scale). The cell membrane is between them, and both boxes are the same size. No arrows are drawn yet.

7. 6.

   Outside oxygen falls until it matches the inside: 5 dots and 5 dots. What happens to oxygen now, Luz?

   • It turns into water
   • It rushes out of the cell
   • It keeps crossing, with no overall change
   • Its particles stop moving

8. Table (model data) from a teacher's demonstration, dots on side 2 of a membrane, starting with 16 dots on side 1

   time (minutes)	warm trial	cold trial
   0	0	0
   5	6	3
   10	8	5

9. 7.

   Each trial evens out at 8 dots on side 2. Which trial evened out first, Milo?

   • The warm trial
   • Neither by 10 minutes
   • The cold trial
   • Both at 5 minutes
10. 8.

    A teacher compares a light gas and a heavy gas at the same temperature. Which spreads faster, Pia?

    • The lighter gas
    • The heavier gas
    • Both at the same speed
    • Neither gas spreads
11. 9.

    Tala says a cell spends energy to pull oxygen in by diffusion. Agree or disagree?

    • Disagree: diffusion needs no energy
    • Disagree: oxygen can't cross a membrane
    • Agree: oxygen can't cross without a push
    • Agree: the membrane pumps oxygen
12. 10.

    Zee says oxygen moves into a cell because the cell needs it. Agree or disagree?

    • Agree: oxygen knows where to go
    • Disagree: it moves from fewer to more
    • Agree: the cell spends energy to call it in
    • Disagree: it moves from more to fewer