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Biology questions, chapter 3
Nama / NameKelas / ClassTarikh / Date

Movement of Substances across a Plasma Membrane

45 marks. Use Practice to check each answer as you go, or Exam to answer everything against the clock first.

Section A: objective questions

12 marks
Choose the best answer for each question.
1

Question 1

Which of the following are the two main components of the plasma membrane?
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B
The plasma membrane is a phospholipid bilayer with protein molecules floating in it (fluid mosaic model, p. 46).
For the teacher: Remembering, low difficulty, standard 3.1.2
Textbook p. 46
2

Question 2

Which part of a phospholipid molecule is hydrophobic?
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C
The nonpolar tail repels water (hydrophobic). The polar head is hydrophilic.
For the teacher: Remembering, low difficulty, standard 3.1.2
Textbook p. 47
3

Question 3

What is the function of cholesterol in the plasma membrane?
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D
Cholesterol strengthens and adds flexibility to the bilayer and makes it less permeable to water-soluble substances such as ions. Receptors and antigens are glycoproteins and glycolipids.
For the teacher: Understanding, low difficulty, standard 3.1.2
Textbook p. 47
4

Question 4

What does it mean when the plasma membrane is said to be selectively permeable?
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A
A selectively permeable membrane allows free movement of certain molecules and prevents or limits other substances.
For the teacher: Understanding, low difficulty, standard 3.1.4
Textbook p. 48
5

Question 5

Which substance can diffuse directly through the phospholipid bilayer?
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C
Oxygen is a small nonpolar molecule. Glucose and amino acids are large and need carrier proteins; ions are charged and need proteins.
For the teacher: Understanding, low difficulty, standard 3.2.1
Textbook p. 49
6

Question 6

Which statement about facilitated diffusion is correct?
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B
Facilitated diffusion uses channel or carrier proteins and moves substances down the concentration gradient, so no energy is needed.
For the teacher: Understanding, medium difficulty, standard 3.2.3
Textbook p. 53
7

Question 7

Which is a characteristic of active transport?
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D
Active transport moves substances against the gradient using ATP and carrier proteins (pumps).
For the teacher: Remembering, low difficulty, standard 3.2.3
Textbook p. 54
8

Question 8

Which process in the human body involves active transport?
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A
Glucose and amino acids are absorbed in the villus by active transport. The other three are passive (diffusion or osmosis).
For the teacher: Applying, low difficulty, standard 3.3.2
Textbook p. 57
9

Question 9

Solution X (0.1 M sucrose) and solution Y (0.5 M sucrose) are separated by a selectively permeable membrane that is impermeable to sucrose. What happens?
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B
X has the lower solute concentration (higher water potential), so water moves from X to Y by osmosis. X is hypotonic to Y.
For the teacher: Applying, low difficulty, standard 3.3.3
Textbook p. 58
10

Question 10

Red blood cells are placed in a hypertonic solution. What happens to them?
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C
Water leaves the cells by osmosis so they shrink; this is crenation. Haemolysis is for hypotonic solutions.
For the teacher: Understanding, low difficulty, standard 3.3.5
Textbook p. 59
11

Question 11

Onion epidermal cells are put in a 1.0 M sucrose solution. The plasma membrane is seen pulling away from the cell wall. Which statement explains this?
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A
A hypertonic solution has lower water potential than the cell sap, so water leaves the vacuole by osmosis and the cell is plasmolysed.
For the teacher: Analysing, medium difficulty, standard 3.3.5
Textbook p. 60
12

Question 12

A farmer applied a large amount of fertiliser and his plants wilted. Which is the best explanation?
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D
Dissolved fertiliser makes the soil water hypertonic to the root cell sap. Water leaves by osmosis, the cells are plasmolysed and the plant wilts.
For the teacher: Evaluating, medium difficulty, standard 3.4.2
Textbook p. 65

Section B: structured questions

33 marks
Answer all questions. Write your answers in the spaces provided.
13

Question 13

Diagram 1 shows the structure of the plasma membrane.
Labelled plasma membrane with phospholipid bilayer, proteins and cholesterol
Diagram 1
[1 mark] (a)Name the model of the plasma membrane shown.
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Tick each point you got.
[1 mark] (b)State one function of glycoprotein.
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Any 1 points
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[2 marks] (c)Explain why the model is described as fluid and mosaic.
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For the teacher: Understanding, low difficulty, standard 3.1.2
Textbook p. 46
14

Question 14

Choose how each substance crosses the plasma membrane.
[1 mark] (a)Oxygen moving into a cell
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Simple diffusion
[1 mark] (b)Glucose moving into a cell down its concentration gradient
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Facilitated diffusion
[1 mark] (c)Sodium ions moving out of an animal cell against their gradient
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Active transport
[1 mark] (d)State why glucose cannot pass through the phospholipid bilayer on its own.
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Tick each point you got.
For the teacher: Applying, low difficulty, standard 3.2.3
Textbook p. 53
15

Question 15

The sodium-potassium pump moves three sodium ions out of an animal cell and two potassium ions into the cell.
[1 mark] (a)State the type of transport involved.
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Tick each point you got.
[1 mark] (b)What is the source of energy for the pump?
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[2 marks] (c)Explain how the carrier protein is able to move the sodium ions across the membrane.
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[2 marks] (d)Cellular respiration in the cell is stopped by a poison. Predict what happens to the pump and explain.
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For the teacher: Analysing, medium difficulty, standard 3.2.3
Textbook p. 55
16

Question 16

Potato strips of equal length were soaked in sucrose solutions for 30 minutes. Diagram 2 shows the percentage change in mass of the strips.
Graph of change in mass (%) against sucrose concentration: +20 at 0 M, +14, +8, +2, -4, -10, -16 at 0.6 M
Diagram 2
[1 mark] (a)State the percentage change in mass of the strip in 0.2 M sucrose solution.
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[1 mark] (b)Determine the concentration of sucrose solution that is isotonic to the potato cell sap.
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[2 marks] (c)Explain why the strip in 0.5 M sucrose solution decreased in mass.
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[1 mark] (d)State the condition of the cells in the strip placed in distilled water.
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For the teacher: Analysing, high difficulty, standard 3.4.1
Textbook p. 63
17

Question 17

A drop of blood is added to each of three test tubes: A (4.5% sodium chloride), B (distilled water) and C (0.85% sodium chloride).
[2 marks] (a)Describe what happens to the red blood cells in test tube A.
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[2 marks] (b)Describe what happens to the red blood cells in test tube B.
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[1 mark] (c)Which test tube is suitable for keeping red blood cells? Give a reason.
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For the teacher: Applying, low difficulty, standard 3.3.5
Textbook p. 59
18

Question 18

A housewife soaks vegetables in a strong salt solution to remove pesticides. After a long time the vegetables become limp.
[3 marks] (a)Explain why the vegetables become limp.
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[1 mark] (b)Suggest how the vegetables can be made crisp again.
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For the teacher: Evaluating, medium difficulty, standard 3.3.5
Textbook p. 60
19

Question 19

A school in an island wants to obtain drinking water from seawater by reverse osmosis.
[1 mark] (a)State the property of the membrane that allows this process.
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[2 marks] (b)Explain why pressure must be applied to the seawater.
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[2 marks] (c)A child with diarrhoea is given an isotonic rehydration drink. Explain why.
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For the teacher: Creating, low difficulty, standard 3.4.4
Textbook p. 66