Diffusion, Osmosis & Active Transport (Cambridge (CIE) IGCSE Biology)

Exam Questions

4 hours34 questions
1a
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2 marks

Molecules may move by the process of diffusion.

Define the term 'diffusion'.

1b
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2 marks

Give two reasons why diffusion is important to living organisms.

1c
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3 marks

Fig. 1 is a cross section through a leaf showing the movement of several substances (A, B and C) through the stomata during the day.

TbhePR-e_plant-tissue

Fig. 1

Identify substances A, B and C.

1d
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2 marks

Describe the movement of substance A in Fig. 1.

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2a
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2 marks

Fig. 1 shows an epithelial cell found in the ileum of the digestive system.

food-molecules

Fig. 1

Give one visible adaptation of this cell and state how this would facilitate diffusion of digested food molecules.

2b
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2 marks

There is a steep increase in the number of digested food molecules in the ileum.

Explain the effect this would have on the rate of diffusion of these molecules.

2c
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1 mark

Organisms must transport substances to and from the external environment.

Identify one substance which cells must transport across the cell membrane to support cell functions.

2d
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1 mark

Fig. 2 shows particles of two gases.

diffusion-1

Fig. 2

Sketch the arrangement of the gas particles after 1 hour.

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3a
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2 marks

Water is important for living organisms as many substances are able to dissolve in it.

Give two examples of the importance of water as a solvent in living organisms.

3b
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1 mark

Fig. 1 shows water and a sugar solution separated by a partially permeable membrane.

tVhetXoo_picture3

Fig. 1

State the overall direction in which water molecules will move.

3c
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2 marks

Osmosis occurred in Fig. 1.

Define the term 'osmosis'.

3d
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2 marks

A second beaker, similar to the one from Fig. 1, was set up and placed in a water bath that was 10°C lower than the beaker from Fig. 1.

Explain how the movement of the water molecules would be affected by this decrease in temperature.

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4a
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2 marks

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Fig. 1 shows a root hair cell.

root-hair-cell-1

Fig. 1

Describe how this cell is adapted for absorption of water by osmosis.

4b
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2 marks

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Fig. 2 shows two cells after the effects of osmosis.

osmosis-in-plant-cells-1

Fig. 2

Identify the correct description for each cell by drawing a line between the cell and the box that contains the most accurate description.

4c
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2 marks

A student carried out an experiment on osmosis in plant tissue. They set up their investigation as shown in Fig. 3.

potatos-and-sucrose-1

Fig. 3

Each beaker contained potato discs in a solution of sugar or distilled water. The student found that the potato discs in Beaker 5 decreased in mass.

Explain the reason for this.

4d
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1 mark

Give one example of a variable that would need to be controlled during the experiment from part (c).

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5a
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2 marks

Fig. 1 shows the process of active transport.

active transport

Fig. 1

State two differences between active transport and diffusion.

5b
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1 mark

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Molecule X in Fig. 1 enters the cell by active transport.

Give one example of molecule X.

5c
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3 marks

Molecule X from Fig. 1 requires a carrier protein to enter the cell.

Describe the role of a carrier protein in active transport.

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1a
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2 marks

Fig. 1 is a diagram of a palisade mesophyll cell. 

097031-may-2019-paper-3-q4a-palisade-mesophyll---sq

Fig. 1

Identify and label the nucleus and a chloroplast on Fig. 1.

1b
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6 marks

Fig. 2 shows the same palisade mesophyll cell after it has been placed in a concentrated sugar solution for twenty minutes. 

097031-may-2019-paper-3-q4b-plasmolysed-palisade-mesophyll---sq

Fig. 2

(i)

Describe the changes that have taken place in the cell between Fig. 1 and Fig. 2.

[2]

(ii)

Explain why the cell in Fig. 2 has changed.

[3]

(iii)

Suggest how the cell in Fig. 2 could be treated so that it returned to its original appearance in Fig. 1.

[1]

1c
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4 marks

(i)

State the name of the tissue that transports water up the stem and into a leaf in a plant.

[1]

(ii)

Fig. 3 shows drawings of sections through a root, a stem and part of a leaf in a dicotyledonous plant.

4d3DvDB~_097031-may-2019-paper-3-q4c-dicot-sections---sq

Fig. 3

Identify and label with the letter W, the position of the water transport tissue in each of the root, the stem and the leaf, on Fig. 3.

[3]

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2a
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10 marks

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More than 40 years ago, botanists studied the leaves of broad bean plants and discovered that guard cells control the opening and closing of stomata. They found that stomata were open when the guard cells were turgid.

Table 1 shows some of their measurements.

Table 1

 

closed stomata

open stomata

ion concentration in guard cells /pmol

0.3

2.5

guard cell volume/μm3

4000.0

6500.0

turgor pressure in the guard cells /MPa

2.0

4.8

width of stomatal opening/μm

0.0

8.0

(i)

Ions move into guard cells by active transport.

Describe how the ions move into the guard cells.

[2]

(ii)

Describe and explain how the change in ion concentration causes the guard cell volume to change.

Use the information in Table 1 in your answer.

[6]

(iii)

The botanists left the broad bean plants unattended for three days. During this time the broad bean plants wilted. 

Suggest two environmental factors that can cause plants to wilt.

[2]

2b
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2 marks

Table 2 shows the concentrations of four mineral ions in the roots of a plant and in the surrounding soil.

These minerals are all essential to the health of the plant.

Table 2

mineral ion

concentration in millimoles per gram

plant root

soil

calcium

0.15

0.03

magnesium

0.06

0.02

nitrate

0.68

0.53

potassium

0.26

0.01

Based on the information in Table 2, explain why the plant roots cannot absorb these mineral ions by diffusion.

2c
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2 marks

Calcium ions play a structural role in cell walls and membranes of the plant cell.

Calculate the percentage difference between the concentration of calcium ions inside and outside the plant root, using the data from Table 1.

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3a
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3 marks

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A student decided to investigate the effect of different sugar solutions on the mass of chicken eggs.

They used the following method:

  1. Five eggs were placed in hydrochloric acid for 24 hours to dissolve the eggshell.

  2. The mass of each egg was measured and recorded.

  3. Five beakers were set up; four with 200 cm3 of sugar solution of different concentrations (0.2, 0.4, 0.6 and 0.8 mol dm-3) and one with distilled water (0 mol dm-3).

  4. An egg was place in each of the beakers for 1 hour.

  5. The eggs were removed and dried with a paper towel whereafter the mass of each egg was measured and recorded.

  6. The percentage change in the mass of each egg was calculated and a graph was drawn from these results.

Fig. 1 represents the graph that was drawn of the percentage change in mass.

rtXEV8i4_change-in-mass-of-egg

Fig. 1

Use the information in Fig. 1 to describe the results obtained in each beaker.

3b
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3 marks

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(i)

Use the graph in Fig. 1 to identify the concentration of the sugar solution where the mass of the egg would not change.

[1]

(ii)

Explain why the mass of the egg would not change at the concentration identified at part (i).

[2]

3c
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3 marks

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Explain the results that were obtained in the beaker with a concentration of 0.8 mol dm-3.

3d
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4 marks

Diffusion and osmosis are two ways in which molecules can move.

Compare diffusion and osmosis with each other.

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4a
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3 marks

A group of scientists investigated the rates of absorption of different sugars using two pieces of the intestine.

One of these pieces were treated with cyanide, which is a toxin that prevents cellular respiration from occurring.

The results of the investigation are shown in Table 1.

Table 1

sugar

absorption rate / arbitrary units

healthy intestine

intestine treated with cyanide

A

121

62

B

47

45

C

68

67

D

89

35

Suggest the method by which sugar A, B and C are absorbed by the intestine.

4b
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3 marks

The scientists concluded that sugar D is absorbed by active transport.

Explain how they came to this conclusion by using evidence from Table 1.

4c
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2 marks

One of the scientists states that 'All four of the sugars investigated could be absorbed by diffusion'.

Determine whether this statement is correct by using the information in Table 1 and your knowledge of diffusion.

4d
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4 marks

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The wall of the intestine contains smooth muscle cells which convert glucose into glycogen. Glycogen is insoluble in water which makes it very suitable as an energy storage molecule.

Using your knowledge of osmosis, suggest an explanation as to why it is important for glucose to be stored as glycogen in muscle cells.

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5a
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1 mark

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Fig. 1 shows two plant cells, each placed in a solution with a different concentration.

plant-cells_hypertonic

Fig. 1

Which of the plant cells above (A or B) was placed in a solution that was more dilute than the cell contents?

5b
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4 marks

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Explain what has happened to the plant cell you identified in part (a).

5c
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4 marks

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When placed in different solutions, animal cells will also change.

Fig. 2 below shows a red blood cell.

red-blood-cell

Fig. 2

(i)

Describe what would happen if a red blood cell was placed in a solution that was more dilute than the cell contents.

[2]

(ii)

Explain why the description at part (i) would be different from what would happen to a plant cell.

[2]

5d
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3 marks

Hereditary spherocytosis is a rare inherited condition that produces red blood cells with an abnormal spherical shape, as shown in Fig. 3.

red-blood-cell_spherocytosis

Fig. 3

Suggest the possible impact of this condition on a sufferer.

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1a
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3 marks

Particulate matter (PM) refers to the small particles in air pollution which can irritate the airways and caused damage to the alveoli. Alveoli are tiny air sacs in the lungs across which gas exchange by diffusion occurs.

Fig. 1 shows the structure of an alveolus with a capillary running next to it.

structure-of-an-alveolus

Fig. 1

If concentrations of PM are high, the epithelium cells of the alveoli may be killed and replaced with unspecialised cells resulting in:

  • Fewer functioning alveoli

  • Thickening of alveolar walls

Explain how particulate matter would affect the process of gas exchange in human lungs.

1b
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3 marks

Fig. 2 shows the results of an investigation into the concentration of particulate matter and the percentage of dead alveolar epithelium cells after 48 of exposure.

particlate-matter-1

Fig. 2

Scientists studied 31 080 alveolar epithelium cells in this study.

Calculate how many more cells died after 48 hours of exposure to 1 000 µg cm-3 of particulate matter than after 48 hours of exposure to 50 µg cm-3 of particulate matter.

1c
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2 marks

Oxygen is required for the process of cellular respiration in cells. People living in urban areas with high levels of air pollution will often suffer from fatigue (feeling tired).

Use the information provided in part (a) and (c) to suggest an explanation for this.

1d
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4 marks

Other than diffusion, movement of molecules in the body could also occur by osmosis and active transport.

Compare osmosis and active transport with each other.

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2a
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5 marks

A student carried out an investigation into the effect of osmosis on plant tissue. 

They cut a potato into cubes and recorded the change in mass over a 30 minute period.

Fig. 1 shows the results the student obtained from one cube of potato.

osmosis-and-potatos-1

 Fig. 1

Describe and explain the trend shown on the graph.

2b
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2 marks

The potato cube from Fig. 1 had an initial mass of 2.5 g.

Calculate the percentage increase that the potato cube had shown after 15 minutes.

2c
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2 marks

The student repeated the investigation but with the beaker placed in a water bath at 30°C.

Draw a second line on the graph to show the trend expected from these results.

2d
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4 marks

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Explain your line drawn for part (c).

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3a
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4 marks

Plants transport sugars in the form of sucrose in phloem sieve tubes. Companion cells are located next to phloem sieve tubes and are responsible for moving sucrose into the tubes for transport.

Fig. 1 shows part of a companion cell and the mechanism by which it moves sucrose into the cytoplasm so that it can be transported into the sieve tubes.

companion-cell

Fig. 1

Sucrose enters the companion cells via a cotransporter protein which will only transport sucrose in the presence of hydrogen ions (H+). This is represented by process B in Fig. 1.

The companion cells will transport H+ out of the cytoplasm by process A so that it can re-enter the cell via the cotransporter protein, allowing sucrose to enter the cell at the same time.

Use the information in Fig. 1 to describe how H+ is transported out of the companion cell by process A.

3b
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2 marks

Process B in Fig. 1 is a passive process.

Explain what is meant by the term 'passive process' with reference to process B.

3c
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3 marks

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High temperatures will change the shape of the proton pump involved in process A.

Explain why sucrose won't be able to enter the companion cell in this scenario.

3d
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3 marks

Once sucrose enters the companion cell cytoplasm, it is quickly transported into the phloem sieve tubes to be taken to other parts of the plant.

Based on your knowledge of diffusion, suggest a possible explanation for this quick transport out of the companion cells.

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4a
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3 marks

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Diabetes insipidus is a disease that results in a large amount of dilute urine being excreted by the kidneys. This leads to blood which is more concentrated than normal.

Explain the effect that diabetes insipidus may have on red blood cells.

4b
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2 marks

One of the symptoms of diabetes insipidus is blue fingernails, which indicates a lack of oxygen.

Suggest an explanation for this.

4c
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3 marks

Central diabetes insipidus is a form of the disease that is believed to have a negative effect on the bone density of a sufferer which may leave them with an increased risk of sustaining fractures.

A study was conducted on the effect of central diabetes insipidus on the risk of sustaining fractures.

The study was done at a hospital and included men and women between the ages of 45 and 65 that were admitted with bone fractures.

  • Men and women were divided up into two groups each; those with diabetes insipidus and those without.

  • Each of the four groups consisted of 250 individuals.

  • The data gathered was used to calculate the percentage prevalence of fractures in each group.

Fig. 1 shows the results of this study.

emvts0eg-picture2

Fig. 1

Calculate the difference in the number of men suffering from fractures between those with diabetes insipidus and those without. Show your calculations.

4d
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4 marks

The scientists concluded that diabetes insipidus does increase the risk of sustaining fractures.

Evaluate this conclusion.

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5a
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2 marks

Monoglycerides are molecules made up of glycerol and one fatty acid tail. They are absorbed into the epithelial cells of the small intestine by diffusion across the cell membrane.

Some people suffer from coeliac disease that affects the lining of their small intestine.

Fig. 1 compares the lining of the small intestine of a healthy person and a person suffering from coeliac disease.

7vNW9Erc_h-3a

Fig. 1

Based on the information provided, explain the effect that coeliac disease would have on the absorption of monoglycerides.

5b
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3 marks

Fig. 2 shows the rate of uptake of monoglycerides in the small intestine.

monoglycerides-1

Fig. 2

Describe and explain what the graph shows.

5c
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3 marks

Human body temperature is approximately 37 °C, which provides the optimum temperature for activity of protein molecules such as enzymes. 

Suggest why a temperature of 37 °C helps to maximise the rate of transport of substances across the cell membrane.

5d
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3 marks

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Fig. 3 shows the concentration of sugars in three different cells. X, Y and Z.

osmosis-from-cell-to-cell-1

Fig. 3

Describe and explain the movement of water between the cells in Fig. 3.

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