Movement of Materials In and Out of the Cell

26 Grade 8 Integrated Science questions on Movement of Materials In and Out of the Cell, with worked marking schemes. 26 questions are available on this topic in full.

1. Question 1

   1 mark

   The movement of water from a region of high concentration to a region of low concentration through a semi-permeable membrane is called

   A. osmosis

   B. filtration

   C. diffusion

   D. active transport

   (1 mark)

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2. Question 2

   3 marks

   Explain the process of osmosis and give one example of osmosis in living organisms.

   (3 marks)

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3. Question 3

   3 marks

   Salt is often added to preserve meat and fish in many Kenyan homes. Using your knowledge of osmosis, explain how salting helps to preserve the food.

   (3 marks)

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4. Question 4

   5 marks

   (a) Define the term diffusion. (2 marks)

   (b) A piece of fresh Irish potato is placed in concentrated salt solution and left for one hour. State and explain the observation made on the potato. (3 marks)

   (5 marks)

   Marking scheme

   (a) Diffusion is the net movement of particles (molecules or ions) from a region of higher concentration to a region of lower concentration until they are evenly distributed. (2 marks) (b) Observation: the potato becomes soft/flaccid and decreases in size/mass (shrinks). Explanation: the salt solution is more concentrated (hypertonic) than the cell sap, so water moves out of the potato cells by osmosis, from the region of higher water concentration (inside the cells) to the region of lower water concentration (the salt solution), causing the cells to lose water. (3 marks)

5. Question 5

   1 mark

   A wilting plant can recover when watered because water enters the cells by

   A. respiration

   B. diffusion

   C. osmosis

   D. active transport

   (1 mark)

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6. Question 6

   1 mark

   A drop of ink is placed in a beaker of still water and slowly spreads until the whole beaker is coloured. This spreading is an example of:

   A. Diffusion

   B. Evaporation

   C. Osmosis

   D. Active transport

   (1 mark)

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7. Question 7

   1 mark

   A red blood cell is placed in pure (distilled) water. What is likely to happen to it?

   A. It loses salts by active transport

   B. It remains exactly the same size

   C. It swells and may burst as water enters by osmosis

   D. It shrinks as water leaves by osmosis

   (1 mark)

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8. Question 8

   3 marks

   Explain why the process of active transport is important in the roots of plants, using the uptake of mineral salts as an example.

   (3 marks)

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9. Question 9

   1 mark

   A piece of fresh potato is placed in concentrated salt solution for one hour. What is MOST likely to happen to the potato piece?

   A. It becomes firm and swells as it gains water

   B. It gains salt by diffusion and grows larger

   C. It changes colour due to a chemical reaction

   D. It becomes soft and shrinks as it loses water by osmosis

   (1 mark)

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10. Question 10

    1 mark

    The smell of ugali cooking spreads throughout the house within minutes. Which process explains how the smell reaches all the rooms?

    A. Diffusion of gas particles through the air

    B. Filtration of the smell particles

    C. Osmosis through the walls

    D. Active transport by air molecules

    (1 mark)

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11. Question 11

    4 marks

    Differentiate between diffusion and osmosis.

    (4 marks)

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12. Question 12

    1 mark

    Osmosis is best defined as the movement of:

    A. Gases across the cell membrane against a gradient

    B. Solute particles from high to low concentration through any membrane

    C. Water molecules from a region of low solute concentration to a region of high solute concentration through a semi-permeable membrane

    D. Water from high solute concentration to low solute concentration

    (1 mark)

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13. Question 13

    5 marks

    A learner set up an experiment: a peeled Irish potato was hollowed out to form a cup, filled with concentrated sugar solution, and placed in a dish of water. After two hours the level of the sugar solution had risen.

    (a) Name the process being demonstrated.

    (b) Explain the observation.

    (c) State one precaution the learner should take for a fair experiment.

    (5 marks)

    Marking scheme

    (a) Osmosis (1). (b) Water from the dish (high water concentration) moved through the potato tissue (semi-permeable membrane) into the concentrated sugar solution (low water concentration), so the level of the sugar solution rose (2). (c) Any one precaution (2): use a raw/uncooked potato so the cells are living; ensure there are no leaks; keep the outside water level constant; mark the starting level of the sugar solution. Total 5 marks.

14. Question 14

    1 mark

    When a drop of ink is placed in water, it spreads throughout the water. This process is called

    A. osmosis

    B. diffusion

    C. condensation

    D. evaporation

    (1 mark)

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15. Question 15

    1 mark

    Active transport differs from diffusion because active transport

    A. does not require energy

    B. requires energy

    C. only moves water

    D. only occurs in plant cells

    (1 mark)

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16. Question 16

    3 marks

    (a) Define the term diffusion. (2 marks)

    (b) Give one example of diffusion that takes place in the human body. (1 mark)

    (3 marks)

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17. Question 17

    1 mark

    Diffusion is the movement of particles from a region of

    A. no concentration difference

    B. high concentration to low concentration

    C. equal concentration in both directions

    D. low concentration to high concentration

    (1 mark)

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18. Question 18

    5 marks

    (a) Define the term osmosis. (2 marks)

    (b) Some pieces of fresh potato were placed in concentrated salt solution and left for one hour. State and explain what happened to the potato pieces. (3 marks)

    (5 marks)

    Marking scheme

    (a) Osmosis is the movement of water molecules from a region of high water concentration (dilute solution) to a region of low water concentration (concentrated solution) through a semi-permeable membrane. (b) The potato pieces became soft/flabby and reduced in size (shrank/lost mass). This is because the salt solution is more concentrated (has less water) than the cell sap of the potato cells, so water moved out of the potato cells by osmosis, causing them to lose water and become flaccid.

19. Question 19

    1 mark

    Which structure of the cell controls the movement of materials into and out of the cell?

    A. Vacuole

    B. Nucleus

    C. Cell membrane

    D. Cytoplasm

    (1 mark)

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20. Question 20

    1 mark

    Wilted vegetables (sukuma wiki) become firm and fresh again after being sprinkled with water. This is because water enters the plant cells by:

    A. Combustion

    B. Osmosis

    C. Active transport

    D. Respiration

    (1 mark)

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21. Question 21

    1 mark

    Which process moves substances across the cell membrane AGAINST the concentration gradient and requires energy?

    A. Osmosis

    B. Active transport

    C. Diffusion

    D. Sedimentation

    (1 mark)

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22. Question 22

    6 marks

    State three differences between diffusion and active transport.

    (6 marks)

    Marking scheme

    Any three differences (2 marks each): Diffusion moves particles from high to low concentration (down the gradient) while active transport moves them from low to high (against the gradient); Diffusion does NOT require energy while active transport requires energy (ATP); Diffusion does not need a carrier and can occur in non-living systems while active transport uses carrier proteins and occurs only in living cells. Award up to 6 marks.

23. Question 23

    4 marks

    (a) Define osmosis.

    (b) Explain why a fresh potato slice placed in a strong sugar solution becomes soft and shrinks.

    (4 marks)

    Marking scheme

    (a) Osmosis is the movement of water molecules from a region of high water (low solute) concentration to a region of low water (high solute) concentration through a semi-permeable/selectively permeable membrane (2). (b) The sugar solution has a lower water concentration than the potato cell sap, so water moves out of the potato cells by osmosis into the solution, causing the cells to lose water and shrink, making the potato soft (2).

24. Question 24

    5 marks

    (a) Define the term diffusion. (2 marks)

    (b) A few drops of ink are added to a beaker of still water and after some time the whole beaker turns the colour of the ink. Name the process responsible and explain what happens to the ink particles. (3 marks)

    (5 marks)

    Marking scheme

    (a) Diffusion is the movement of particles (molecules) of a substance from a region of high concentration to a region of low concentration until they are evenly distributed. (b) The process responsible is diffusion. The ink particles move from where they are highly concentrated (where the drops were added) to areas of lower concentration in the water, spreading out until the ink particles are evenly distributed throughout the beaker, giving the whole beaker a uniform colour.

25. Question 25

    1 mark

    If a plant cell is placed in a concentrated salt solution, the cell will

    A. gain water and swell

    B. burst open

    C. lose water and shrink

    D. remain unchanged

    (1 mark)

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26. Question 26

    1 mark

    The random movement of particles from a region of high concentration to a region of low concentration is called:

    A. Osmosis

    B. Diffusion

    C. Active transport

    D. Filtration

    (1 mark)

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