Syllabus Edition

First teaching 2023

First exams 2025

|

Cell Structure (SL IB Biology)

Exam Questions

3 hours53 questions
1a
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2 marks

The diagram below is of an Amoeba. The actual size, measured between points A and B, is 320 µm. 

When a student measured the same distance using an image from a microscope they determined the size to be 128 000 µm.

1-1-e-4a-paper-2

Calculate the magnification of this Amoeba. Show your working.

1b
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2 marks

Whilst examining the Amoeba the student also measured the length of the organelles present, including the nucleus. The length of the nucleus on the microscope image was 28 000 µm. 

Assuming the same magnification as part (a), calculate the actual size of the nucleus. Give your answer in mm.

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2a
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4 marks

The micrograph below shows a single-celled organism known as Euglena.

Draw a biological drawing of the Euglena.

1-1-e-5a-paper-2

2b
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1 mark

State an addition to any biological drawing that would be necessary to allow the viewer to ascertain the true size of the object being pictured.

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3a
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2 marks

The diagram below shows a magnified view of a cell.

1-2-e-1a-paper-2

State the names of structures L and N.

3b
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1 mark

Another structure that would likely be present in the cell seen in part (a) is the Golgi apparatus.

State the function of the Golgi apparatus.

3c
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2 marks

State, with a reason, the type of cell (prokaryotic or eukaryotic) featured in part (a). 

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4a
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2 marks

In order to be considered living, organisms carry out the functions of life. 

Define the following:

i)

Homeostasis

ii)
Excretion
4b
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4 marks

The unicellular group known as the dinoflagellates can be found in fresh water, where they prey upon other protozoa.

Dinoflagellates contain eyespots and two flagella, enabling them to find and move towards prey. Every day they undergo mitosis and in some cases this forms ‘red tides’. 

Identify the functions of life that have been described in this passage on dinoflagellates.

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5a
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1 mark

The image below shows pollen grains viewed under a light microscope.

pollen-grains-under-microscope

Ergriffi, CC BY 4.0, via Wikimedia Commons

State the type of microscope that would enable scientists to examine the pollen grains in more detail.

5b
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2 marks

List two advantages of the type of microscope stated in part (a). 

5c
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3 marks

List three differences between prokaryotic and eukaryotic cells.

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6a
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1 mark

The image shows an internal cellular structure as viewed under an electron microscope.

1-2-e-4c-paper-2

Identify the cell structure shown.

6b
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1 mark

State the name the structure labelled X.

vacuole-to-label

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7a
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5 marks

The image below shows an electron micrograph of a palisade mesophyll cell.

e-5a

Draw a labelled diagram of this cell.

7b
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2 marks

(i) State the main function of the palisade cell.

(ii) Name the organelle that the palisade cell contains many of in order to carry out its main function.

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8
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3 marks

Explain the advantages of using an electron microscope to analyse muscle tissue. 

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1a2 marks

The drawing below shows part of a plant cell as seen with an electron microscope. The scale bar (measuring 45 mm in length) on this drawing represents a length of 10 μm.

q2a-1-1-cells-theory-medium-ib-hl-biology-sq

Calculate the magnification of the drawing.

1b2 marks

Calculate the actual width of the cell in part (a) between A and B.

Give your answer in micrometres (µm).

1c2 marks

Identify two ways in which striated muscle fibres (fused muscle cells) differ from the cell shown in part (a). 

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2a2 marks

The diagram below is of a mitochondrion at a magnification of ×20 000. The distance between points A and B in the diagram is 6.4 cm.

q4a-1-1-cells-theory-medium-ib-hl-biology-sq

Calculate the actual length of this mitochondrion in micrometres (µm).

2b2 marks

The circumference of a mitochondrion, labelled C in the diagram in part (a), is 1.5 µm. A student is making an accurate scale model of a mitochondrion for a school science project and wants to magnify a mitochondrion 50,000 times.

What will the circumference of the student’s model be, in cm?

2c
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1 mark

The mitochondrion in part (a) is responsible for the process of cell respiration.

Identify the 'function of life' of which respiration is an example.

2d2 marks

Briefly outline the key ideas that make up cell theory.

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3a6 marks

Describe how a student would prepare a microscope slide containing a sample of cells from a piece of plant tissue, and how the student would view this sample under a light microscope.

3b
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2 marks

Name the two pieces of equipment, used as accessories to a standard light microscope, to measure the size of the specimen being viewed.

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4a2 marks

A student drew a eukaryotic cell from an electron micrograph.

q1a-1-2-cells-origin-medium-ib-hl-biology-sq

Identify F and H in the student’s drawing.

4b3 marks

The student concluded that the eukaryotic cell in part (a) was not a plant cell.

Explain why they came to this conclusion.

4c2 marks

State the function of mitochondria.

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5a2 marks

The electron micrograph below shows part of a palisade mesophyll cell.

q2b-1-2-cells-origin-medium-ib-hl-biology-sq

Identify structures A and D.

5b1 mark

The diagram below shows a drawing of part of an animal cell as seen through an electron microscope.

q2c-1-2-cells-origin-medium-ib-hl-biology-sq

Suggest why the shapes of the two organelles labelled O in the diagram appear different.

5c2 marks

Describe the function of organelle N in the diagram in part (b).

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6a4 marks

Phospholipids and peptidoglycan are two biological molecules found in prokaryotic cells. The drawing below shows part of a prokaryotic cell.

q3a-1-2-cells-origin-medium-ib-hl-biology-sq

(i)
Identify (P, Q, R, or S) and name the structure in which phospholipids are the main biological molecule.

 

(ii)
Identify (P, Q, R, or S) and name the structure in which peptidoglycan is the main biological molecule.
6b2 marks

In certain conditions some prokaryotic cells can divide every 25 minutes.

With a starting population of 2.45 × 103 cells, and assuming that each cell divides every 25 minutes, calculate the number of cells present after 3.75 hours. Assume that no cells die during this time.

6c1 mark

Identify structure R in the diagram in part (a).

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7a2 marks

Scientists used an electron microscope to study the structure of a unicellular, eukaryotic organism known as an amoeba.

Explain why scientists used an electron microscope to study the structure of an amoeba.

7b3 marks

State three structures in an amoeba cell that the scientists would not have been able to view using a light microscope.

7c2 marks

The electron micrograph below shows a spore from a fungus (Tilletia controversa) that affects wheat crops.

q4c-1-2-cells-origin-medium-ib-hl-biology-sq

State, with a reason, the type of electron microscope used to produce the micrograph above.

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83 marks

The diagram below shows a drawing of part of an animal cell as seen through an electron microscope.

q5a-1-2-cells-origin-medium-ib-hl-biology-sq

Large numbers of organelle O are found in small intestine epithelial cells.

Explain why these cells are adapted in this way.

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97 marks

Compare and contrast the structures of prokaryotic and eukaryotic cells.

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1
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2 marks

The Jacobson’s organ in Pseudonaja textilis (the eastern brown snake) is a pair of crescent-shaped chambers where odour molecules are deposited by the tongue when it retracts back into the mouth.

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

Suggest why Jacobson’s organ is crescent-shaped rather than straight.

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2a
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4 marks

The image below is a photomicrograph of a transverse section through part of a stem.

6Z9U726T_plant_stem_255_07_cross-section_of_stem_of_aristolochia

Doc. RNDr. Josef Reischig, CSc., CC BY-SA 3.0, via Wikimedia Commons

Draw a large tissue plan diagram of this part of the stem.

2b
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2 marks

A student used a light microscope to study the plant stem pictured in part (a). The diagram below shows the stage micrometer scale that was used to calibrate an eyepiece graticule. 

The length of one division on this stage micrometer is 0.01 mm.

Note that one division is the distance between two adjacent vertical lines. 

1-1-h-4b-paper-21

Using this stage micrometer, calculate the actual length of one eyepiece graticule division.

2c
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1 mark

The photomicrograph below was taken using the same lenses as part (b).

The same eyepiece graticule was also used; a section of that graticule is shown under the image below.

distance-graticule

Use the calibration of the eyepiece graticule unit from part (b) and the information in the photomicrograph to estimate the actual length of the plant tissue from A to B. Give your answer in μm.

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3
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2 marks

Creutzfeldt-Jakob disease is a rare neurodegenerative disease caused by abnormally-folded proteins found in the brain. Proteins that trigger abnormal folding are called prions.

Suggest why scientists have not classified prions as living.

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4a
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2 marks

The diagram below shows a cell.

JU0wuM99_cell

Determine, with a reason, whether or not the cell is a eukaryotic cell.

4b
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2 marks

Outline why compartmentalisation is an advantage for this cell. 

4c
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2 marks

A student suggested that they would be able to view structure X at the highest magnification with their light microscope. 

Explain why the student is not correct.

4d
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1 mark

Identify one specific process taking place inside the cell in part (a).

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5
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2 marks

A student drew this eukaryotic cell.

1-2-h-2a-paper-2

Identify structures E and G.

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6a
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4 marks

Below are three electron micrographs showing organelles found within a cell.

Cell organelles micrograph

(i)

Identify the organelles J, K, and L.

[3]

(ii)

Identify one structural feature of these organelles that enables them to function efficiently.

[1]

6b
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2 marks

Compare the structure and function of the organelles in micrographs K and L.

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7a
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3 marks

Draw a labelled biological diagram of the bacterial cell below.

bacteria-cell-to-draw

Pradana Aumars, CC0, via Wikimedia Commons

7b
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4 marks

The image shows a cell of the immune system.

h-4d

(i)

Identify structure R

[1]

(ii)

Deduce, with a reason, the function of this cell.

[3]

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8
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7 marks

Euglena gracilis is a unicellular eukaryotic cell. It can gain nutrients from its surroundings by endocytosis and is also capable of carrying out photosynthesis.

Discuss the theory that explains how Euglena could have evolved.

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