Diffusion across a cell membrane

Grade 7 Science Worksheet - Challenge Me

Circle the best answer.

1. 1.

   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?

   • 9 on each side
   • 14 on each side
   • 0 outside and 22 inside
   • 11 on each side
2. 2.

   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?

   • 0 inside and 24 outside
   • 12 on each side
   • 16 on each side
   • 10 on each side
3. 3.

   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 moves in faster
   • Oxygen stops moving in
   • The cell must push it in
   • Oxygen starts moving out
4. 4.

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

5. 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.

6. 5.

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

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

7. 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

8. 6.

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

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

9. Model data

   trial	dots on side 1 at the start	dots on side 2 at the start	dots crossing in the first minute
   trial A	20	0	6
   trial B	12	8	1

10. 7.

    Which claim does the table support, Noah?

    • The difference makes no change
    • A bigger difference makes diffusion faster
    • A smaller difference makes diffusion faster
    • Dots cross just when a side is empty
11. 8.

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

    • The heavier gas
    • Both at the same speed
    • The lighter gas
    • Neither gas spreads
12. 9.

    Ren says diffusion stops when the sides are even because the particles stop moving. Agree or disagree?

    • Agree: even sides mean still particles
    • Disagree: they pile up on one side
    • Disagree: they keep moving both ways
    • Agree: the membrane locks them
13. 10.

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

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