Syllabus Edition

First teaching 2023

First exams 2025

|

Movement into & out of Cells (CIE AS Biology)

Exam Questions

3 hours45 questions
1a
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1 mark

Complete the following sentence.

The size of an organism is _____________ proportional to its surface area to volume ratio. 

1b
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1 mark

In an experiment using agar blocks immersed in a diffusion solution, the blocks are made up containing sodium hydroxide and a universal indicator solution.

Suggest a suitable solution to immerse these blocks to examine diffusion.

1c
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2 marks

Two organisms are described in Table 1.

Table 1

  organism A organism B
 surface area / cm2 18 970 79.8
 volume / dm3 70 0.019
 SA: VOL ratio    

Complete Table 1 by calculating the missing surface area to volume ratios.

Do not include units.

1d
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2 marks

Table 1 from part (c) shows two organisms, A and B.

One of these is a mouse, the other is a human. Identify which animal is represented by A.

Give a reason for your answer.

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2a
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4 marks

Fig. 1 shows a section of membrane from a cell.

cell-membrane

Fig. 1

Substances can pass across this membrane by diffusion or by facilitated diffusion.

With reference to transport across a membrane such as that in Fig.1, compare and contrast diffusion with facilitated diffusion.

2b
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3 marks

Fig. 2 shows three different membrane proteins.

The boxes on the right show their various descriptions.


LbacbVLs_cie-ial-4-2-q2be---sq

Fig. 2

Join the boxes on the left with the appropriate box on the right with three straight lines.

2c
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5 marks
Compete the following passage about osmosis using appropriate words, some of which should be topic-specific keywords. 

Do not use the word 'osmosis' as one of your answers. 

Plant roots absorb _______ by osmosis from the surrounding soil. It moves by a process of _______ from an area of _______ concentration to an area of _______ concentration across a _______ membrane. 

2d
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3 marks
(i)

Complete the following statement:

As solute concentration increases, water potential ___________.

[1]

(ii)

Explain your choice of word in part (d) (i).

[2]

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3a
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3 marks

Define the term active transport. 

3b
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3 marks

List three factors that affect the rate of diffusion of substances across a membrane.

3c
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1 mark

State the name of the process by which materials are transported from structures S to R in Fig. 1 below

1-3-e-2c-paper-2

Fig. 1

3d
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1 mark

Name one material that could be transported from structure S to R.

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4a4 marks

Figure 1 below shows a cell surface membrane and some molecules of a small, nonpolar substance known as substance X. 

Figure 1

7FyW42_E_2

Predict and explain what will happen to substance X in Figure 1.

4b1 mark

Give a possible name for substance X.

4c2 marks

Substance Y is a large molecule and is not lipid-soluble. Describe how substance Y  would travel across a cell membrane from an area of high to low concentration. 

4d3 marks

Figure 2 shows a molecule (X) that is about to be transported across a cell membrane.

Figure 2

q4b-2-4-cell-membrane-and-transportation-easy

Describe the events that would take place in order for molecule X in Figure 2 to move from the exterior of the cell into the cytoplasm.

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5a2 marks

Complete Table 1 by placing a tick (✓) in the appropriate boxes.

Table 1

 

Simple diffusion

Osmosis

Facilitated diffusion

Active Transport

Movement of glucose from high to low concentration

       

Movement down a concentration gradient

       

Movement of water from high water potential to low water potential.

       

Movement of oxygen from the plasma into a red blood cell

       
5b3 marks

Figure 1 below shows a group of onion cells viewed under an optical microscope. 

Figure 1

e5cAMwLp_3

Explain the appearance of the cytoplasm that can be seen in Figure 1.  

5c2 marks

A student took a cheek cell sample using a cotton swab and placed the cells into a test tube containing pure water. Predict what would happen to the cheek cells in the test tube.

5d2 marks

The onion cells from part b) were also placed into pure water, but the effect on these cells were slightly different. State how the effect would be different and explain why.

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1a2 marks

A group of students investigated the effect of concentration gradient on the rate of diffusion. They filled a length of Visking tubing with a glucose solution of known concentration and suspended the tubing in a boiling tube filled with distilled water. Samples from the water surrounding the Visking tubing were removed at regular time intervals and tested for levels of glucose using Benedict's test. The experiment was repeated several times with different concentrations of glucose placed in the Visking tubing. 

The students plotted a graph of glucose concentration against diffusion rate. Fig. 1 shows a representation of the results.

4-2-fig-1-1

Fig. 1

Describe and explain the results shown in Fig. 1

1b2 marks

The students repeated the experiment from part a) at a temperature that was 10 °C lower.

Suggest how this would affect the results of the investigation.

1c3 marks

The students conducted a similar investigation by using animal cells placed in glucose solutions of different concentrations. The rate at which glucose entered the cells was determined for each glucose concentration.

The results of this investigation are shown in Fig. 2.

4-2-fig-1-2
Fig. 2

i)
Identify the specific type of membrane transport by which glucose enters the cells in Fig. 2

[1]

ii)
Suggest an explanation for your answer to part i).
[2]
1d3 marks

The investigation in part c) was carried out at room temperature.

Predict the possible outcome if the investigation in part c) were conducted at 60 °C and state a reason for your answer.

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2a
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2 marks

An investigation was conducted to estimate water potential in plant tissue. The following method was used:

  • The investigators made a range of dilutions of a 1 mol dm-3 solution of sodium chloride.
  • A cork borer was used to cut three potato cylinders for each sodium chloride concentration.
  • The initial mass of each potato cylinder was recorded.
  • The potato cylinders were placed in boiling tubes, each containing 10 cm3 of sodium chloride solution of a different concentration. One of the boiling tubes contained only distilled water.
  • The boiling tubes were placed in a water bath at 25 °C and left for a period of 5 hours.
  • The final mass of each potato cylinder was measured and recorded for each sodium chloride solution.
  • The mean initial and final mass was calculated for each sodium chloride solution.

The results for this investigation is shown in Table 1

Table 1

Concentration of sodium chloride solution / mol dm-3 Mean initial mass / g Mean final mass / g Mean % change in mass / %
0.00 4.50 4.95 10
0.25 4.52 4.60 1.8
0.50 4.51 4.51 0
0.75 4.51 4.30  
1.00 4.50 4.27 -5.1

Calculate the mean percentage change in mass of the potato cylinders in the 0.75 mol dm-3 sodium chloride solution. Show your working.

2b2 marks

Explain why there was no change in mass for the potato cylinders in the 0.5 mol dm-3 sodium chloride solution.

2c2 marks

Explain the change in mass that occurred in the potato cylinder placed in the boiling tube containing distilled water.

2d3 marks

Sketch one of the potato cells that was kept in the 1.00 mol dm-3 sodium chloride solution. Label the cell wall, cell membrane and cytoplasm in your diagram.

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3a3 marks

Active transport plays an important role in the absorption of the products of digestion in the small intestine.

Compare the process of active transport with the process of facilitated diffusion.

3b3 marks

Fig.1 illustrates another type of membrane transport.

4-2-fig-3-1
Fig. 1

i)

Identify the type of transport that is illustrated in Fig. 1

[1]

ii)
Describe the process identified in part i)

[2]

3c2 marks

A gastric chief cell is a type of gland cell that secretes pepsinogen and other digestive enzymes in the stomach.

Fig. 2 shows a diagram of a gastric chief cell.

4-2-fig-3-2
Fig. 2

Gastric chief cells contain a large number of structure X.

Explain the reason for this.

3d2 marks

Describe the process by which gastric chief cells will release these digestive enzymes into the stomach.

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4a4 marks

Fig.1 shows a light micrograph of a series of onion cells that have been placed in distilled water for several hours.

4-2-fig-5-1
Fig. 1

Describe the events that led to the appearance of the cells in Fig. 1

4b2 marks

Fig.2 shows another set of onion cells.

4-2-fig-5-2
Fig. 2

Explain why the cells in Fig.2 differ in appearance from the cells shown in Fig. 1.

4c3 marks

Emphysematous pyelonephritis (EPN) is a very rare complication that can develop as a result of an untreated kidney infection. It is a severe infection during which bacteria destroy kidney tissue, eventually leading to kidney failure. If kidney failure is left untreated the kidneys are unable to regulate the amount of water in the body and the blood plasma becomes more dilute than normal.

Describe the effect that this would have on red blood cells.

4d2 marks

Explain why changes in cell volume affect animal cells more severely than plant cells.

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5a2 marks

Some scientists investigated the uptake of magnesium ions in rice plants. They divided the plants into two groups and placed their roots in solutions containing radioactive magnesium ions.

   Group Y: plants had a substance that inhibited respiration added to the solution
   Group Z: plants did not have the respiratory inhibitor added to the solution

The scientists calculated the total amount of magnesium ions absorbed by the plants every 5 minutes. Their results are shown in the graph in Figure 1 below:

Figure 1 

q3a-fig-1-2-4-medium-aqa-a-level-biology

Calculate the ratio of the mean rate of uptake of magnesium ions in the first 20 minutes to the mean rate of uptake of magnesium ions in the second 20 minutes for group Z plants. Show your working.

5b4 marks

Consider the graph in Figure 1. Explain the results of the students’ investigation.

5c2 marks

Using the graph in Figure 1, calculate the rate of uptake of magnesium ions for group Y plants during the investigation. Give suitable units.

5d
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3 marks

State the names of three other substances that would not be absorbed into the group Y plants.

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1a
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2 marks

A student investigated the effect of changing the size of a cube on the rate of diffusion.

Coloured agar was created using a dilute sodium hydroxide solution and universal indicator. The agar was cut into cubes of different sizes (A to E) and their surface area and volume were calculated in order to determine the surface area to volume ratio.

The cubes were placed into boiling tubes containing 10 cm3 of dilute hydrochloric acid and the time taken for the agar cubes to become colourless was measured and recorded.

The results of the investigation is represented in Table 1.

Table 1

Cube

Surface area
/ cm2

Volume
/ cm3
Surface area: Volume Time taken for the cube to turn colourless / s
A 1.5 0.13 11.5 : 1 175
B 6.0 1.00 6 : 1 256
C 13.5 3.38   312
D 24.0 8.00 3 : 1 384
E 37.5 15.63 2.4 : 1 428

Calculate the surface area to volume ratio for cube C.

Show your work and round your answer to the nearest whole number.

1b
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2 marks

Describe the results shown in Table 1.

1c
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3 marks

Explain the significance of the results shown in Table 1 for living organisms.

1d
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2 marks

Suggest a possible outcome for the investigation described in part (a) if the agar cubes were placed in a more concentrated solution of hydrochloric acid.

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2a
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1 mark

Some membranes are described as semi-permeable; this means that only water and a few small solutes can pass through the membrane.

However, the preferred term to describe most biological membranes is selectively permeable. 

Explain why selectively permeable is the preferred term for biological membranes. 

2b
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2 marks

Diffusion can be studied using visking tubing. Visking tubing (or dialysis tubing) is a plastic-like material that water and small solute molecules can pass through.

Students set up an investigation in which equal volumes of each of the following solutions were placed into separate visking tubings:

0.7 mol dm-3 sodium chloride

0.7 mol dm-3 glucose

The visking tubings, each of the same size, were placed in distilled water and maintained at a constant temperature of 23°C. The volume and mass of the bags were measured at 5 minute intervals for 160 minutes.

The data recorded is shown below.

1-3-h-3b-paper-2

Calculate the rates of increase in mass and in volume for the visking tubing containing glucose solution during the first 30 minutes.

2c
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3 marks

Compare and contrast the rates of change in mass for the two visking tubings.

2d
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2 marks

Explain why the volumes of both visking tubings increases over time.

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3a
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1 mark

The graph in Fig.1 shows the increase in mass of a potato chip when placed into a solution.

osmosis-and-potatos-1

Fig.1 

Describe the water potential of the solution at 25 minutes.

3b
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3 marks

Explain the trend shown in Fig.1 from 0-24 minutes.

3c
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4 marks

Contrast the processes of osmosis and exocytosis.

3d
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4 marks

Explain the role of exocytosis in the digestion of starch in the small intestines.

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4a6 marks

Design an experiment to estimate the glucose concentration of the cell contents of sweet potato tuber. The following equipment has been provided. 

  • Sweet potato
  • 1 mol dm3 glucose solution
  • Cork borers
  • Other common laboratory supplies and reagents.

Outline the steps you would take and the way that you would process the data that you would generate. 

4b3 marks

Sketch a graph of the expected results from the experiment in question 3a). 

4c2 marks

Define the term, ‘water potential’ and explain why values of water potential are expressed in kilopascals (kPa).

4d2 marks

Explain why an aqueous solution has a lower water potential than pure water. 

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5a
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3 marks

A plant palisade mesophyll cell is 4 μm in width and depth, and 25 μm in length.

Its shape is approximately cuboid. 

Calculate the surface area to volume ratio of this cell. Show your working.

5b
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3 marks

If the palisade cell in part (a) has a large central vacuole, so that the cytoplasm (not including the vacuole) extends inward 500 nm from the plasma membrane of the cell. 
    
Calculate the surface area to cytoplasmic volume ratio. Show your working.

5c
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3 marks

Explain the importance of the surface area to volume ratio to a growing bacterial cell.

5d
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3 marks

Palisade mesophyll cells and bacterial cells are both approximately cuboid in shape. 

Explain the benefit of this shape for the functioning of the cell. 

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