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O Level Biology: Movement into and out of Cells MCQs — Biology

18 multiple-choice questions on O Level Biology: Movement into and out of Cells from Biology, each with the correct answer and, where available, a teacher's explanation. Read through them to revise the chapter, then practise the same questions one by one to test yourself.

1. Potato strips placed in a concentrated sugar solution

  1. gain mass
  2. lose mass
  3. stay the same mass
  4. burst

Answer: B) lose mass

Explanation: Water leaves by osmosis into the lower water potential solution. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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2. A potato strip of mass 5.0 g has mass 5.5 g after 30 minutes in water. The percentage change in mass is

  1. −10%
  2. +5%
  3. +10%
  4. +0.5%

Answer: C) +10%

Explanation: (5.5 − 5.0) ÷ 5.0 × 100 = 10%. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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3. A plant cell placed in pure water becomes

  1. burst
  2. flaccid
  3. turgid
  4. plasmolysed

Answer: C) turgid

Explanation: Water enters; the cell wall stops it bursting. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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4. Why do root hair cells contain many mitochondria?

  1. To make cellulose
  2. To photosynthesise
  3. To release energy for active transport
  4. To store water

Answer: C) To release energy for active transport

Explanation: Mitochondria provide energy by respiration. O Level Biology · Topic 3 Movement into and out of Cells · 3.2 Active transport

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5. The energy for diffusion comes from

  1. ATP made in chloroplasts
  2. the kinetic energy of moving particles
  3. respiration
  4. sunlight

Answer: B) the kinetic energy of moving particles

Explanation: Diffusion is passive; particles move randomly. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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6. Root hair cells take in nitrate ions by active transport because

  1. nitrate concentration is higher inside the cell than in the soil
  2. the soil has no water
  3. nitrate concentration is lower in the cell
  4. nitrate is a gas

Answer: A) nitrate concentration is higher inside the cell than in the soil

Explanation: Uptake against the gradient needs energy. O Level Biology · Topic 3 Movement into and out of Cells · 3.2 Active transport

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7. Dialysis tubing filled with sugar solution is placed in water. The tubing swells because

  1. water leaves by osmosis
  2. sugar leaves by active transport
  3. sugar enters by diffusion
  4. water enters by osmosis

Answer: D) water enters by osmosis

Explanation: Water moves into the lower water potential inside. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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8. Why do plants wilt when short of water?

  1. Cells lose turgor and become flaccid
  2. Cells burst
  3. Stomata open wider
  4. Cell walls dissolve

Answer: A) Cells lose turgor and become flaccid

Explanation: Without turgor pressure, the plant loses support. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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9. Which statement is true for both diffusion and osmosis?

  1. They involve only water
  2. They are passive and need no energy from respiration
  3. They need carrier proteins
  4. They move particles against a gradient

Answer: B) They are passive and need no energy from respiration

Explanation: Both are passive processes. O Level Biology · Topic 3 Movement into and out of Cells · 3.2 Active transport

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10. Which would STOP active transport in root hair cells?

  1. More light
  2. More water in the soil
  3. Higher concentration of ions in the soil
  4. Lack of oxygen for respiration

Answer: D) Lack of oxygen for respiration

Explanation: No respiration means no energy. O Level Biology · Topic 3 Movement into and out of Cells · 3.2 Active transport

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11. Diffusion is the net movement of particles from

  1. a lower concentration to a higher concentration
  2. a dilute solution to a concentrated one through a membrane only
  3. a higher concentration to a lower concentration
  4. cell to cell using energy from respiration

Answer: C) a higher concentration to a lower concentration

Explanation: Diffusion is down a concentration gradient. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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12. Active transport moves substances

  1. only water through a membrane
  2. against a concentration gradient using energy from respiration
  3. through the cell wall only
  4. down a concentration gradient without energy

Answer: B) against a concentration gradient using energy from respiration

Explanation: Definition of active transport. O Level Biology · Topic 3 Movement into and out of Cells · 3.2 Active transport

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13. A red blood cell is placed in pure water. What happens?

  1. It shrinks
  2. It becomes plasmolysed
  3. It swells and bursts
  4. Nothing happens

Answer: C) It swells and bursts

Explanation: Animal cells lack a cell wall, so they burst. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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14. Which process needs carrier proteins and energy?

  1. Evaporation
  2. Osmosis
  3. Active transport
  4. Diffusion

Answer: C) Active transport

Explanation: Active transport uses carrier proteins and energy. O Level Biology · Topic 3 Movement into and out of Cells · 3.2 Active transport

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15. Plasmolysis is when

  1. the cell membrane pulls away from the cell wall as water leaves
  2. water enters the cell
  3. the vacuole swells
  4. the cell wall bursts

Answer: A) the cell membrane pulls away from the cell wall as water leaves

Explanation: Plasmolysis follows water loss in concentrated solutions. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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16. Water is important in transport because

  1. it is a source of energy
  2. it is a protein
  3. many substances dissolve in it
  4. it stores fat

Answer: C) many substances dissolve in it

Explanation: Water's solvent action allows transport in plasma and xylem. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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17. Osmosis is the movement of

  1. sugar molecules through a membrane
  2. water molecules through a partially permeable membrane
  3. ions using energy
  4. any particles against a gradient

Answer: B) water molecules through a partially permeable membrane

Explanation: Osmosis refers only to water. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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18. Which change would INCREASE the rate of diffusion?

  1. Reducing the surface area
  2. Increasing the temperature
  3. Reducing the concentration gradient
  4. Increasing the distance

Answer: B) Increasing the temperature

Explanation: More kinetic energy means faster diffusion. O Level Biology · Topic 3 Movement into and out of Cells · 3.1 Diffusion and osmosis

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