AQA A Level Biology: Eukaryotic and Prokaryotic Cell Structure — Practice Questions

These are original questions written for Marlbridge, in the style and at the standard of the examination. They are not reproduced past-paper questions — examination boards hold copyright in their own papers. Use these alongside the official past papers available free from your board.

Related: Eukaryotic and Prokaryotic Cell Structure study guide | Eukaryotic and Prokaryotic Cell Structure revision notes

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Section A

1. Name three organelles found in a eukaryotic cell that are not found in a prokaryotic cell. [3]

2. State what a virus is made of, and explain why viruses are described as acellular. [3]

Section B

3. Explain how the structure of mitochondria relates to their function. [4]

4. Rough endoplasmic reticulum and the Golgi apparatus often work together in a cell.

(a) Describe the structure and role of rough endoplasmic reticulum. [2] (b) Describe the role of the Golgi apparatus and Golgi vesicles. [2] (c) Explain why a cell that secretes large amounts of protein would contain unusually large numbers of both organelles. [2]

5. State three differences between a bacterial cell and a plant cell, other than size. [3]

6. A student states: “Bacteria have a cell wall, so their cell wall must be made of the same material as a plant cell wall.”

(a) Explain why this statement is incorrect. [2] (b) Name the material found in each type of cell wall. [2]

7. Explain why lysosomes are essential to a white blood cell that engulfs and destroys bacteria. [3]

8. Distinguish between the DNA found in a eukaryotic cell’s nucleus and the DNA found in a prokaryotic cell, referring to both its form and its association with protein. [3]

9. Explain why it would be incorrect to describe a virus as “a very small, simple prokaryotic cell”. [2]

10. A cell contains many mitochondria but no chloroplasts. Suggest what type of organism this cell is likely to be from, and justify your answer. [2]

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Answers

1. Any three: mitochondria, chloroplasts, Golgi apparatus, rough/smooth endoplasmic reticulum, lysosomes, a true nucleus [1] [1] [1].

2. A virus consists of genetic material, a capsid (protein coat), and an attachment protein [1] [1]. Viruses are acellular because they are not made of a cell at all [1] — they have no cell-surface membrane, cytoplasm, or ribosomes of their own, unlike even the simplest prokaryotic cell.

3. Mitochondria have a double membrane, with the inner membrane folded into cristae, surrounding a fluid-filled matrix [1] [1]. The folded cristae increase the surface area available for the electron transport chain and ATP synthase [1], while the matrix contains the enzymes for the Krebs cycle, together allowing a high rate of ATP production for aerobic respiration in a compact structure [1].

4. (a) Rough ER is endoplasmic reticulum studded with ribosomes [1], involved in the synthesis and processing/transport of proteins [1]. (b) The Golgi apparatus modifies and packages proteins [1] received from the rough ER, and Golgi vesicles secrete them from the cell [1]. (c) These proteins must be synthesised (rough ER) and then modified, packaged and secreted (Golgi apparatus/vesicles) in large quantity [1], so the cell needs a correspondingly large amount of both organelles to sustain that rate of production and secretion [1].

5. Nucleus — plant cell has a true, membrane-bound nucleus; bacterium has none, with DNA free in the cytoplasm [1]. Organelles — plant cell has membrane-bound organelles; bacterial cytoplasm lacks them entirely [1]. Cell wall — plant cell wall is made of cellulose; bacterial cell wall is made of murein, a glycoprotein [1].

6. (a) Having “a cell wall” does not mean the chemical composition is the same — the two cell walls are made of different materials [1] entirely, despite both being described generically as “a cell wall” [1]. (b) Bacterial cell wall: murein (a glycoprotein) [1]. Plant cell wall: cellulose [1].

7. Lysosomes are membrane-bound organelles containing hydrolytic enzymes [1]. After the white blood cell engulfs a bacterium, a lysosome fuses with the vesicle containing it [1] and releases its enzymes to break down (digest) the bacterium [1].

8. Eukaryotic nuclear DNA is linear and protein-bound (associated with histone proteins, forming chromosomes) [1] [1]. Prokaryotic DNA is a single circular molecule, free in the cytoplasm and not associated with protein [1].

9. A virus is acellular — it is not made of a cell, has no cytoplasm, cell-surface membrane, or ribosomes [1] — whereas even the simplest prokaryotic cell is a living cell with these features; a virus differing only in size or simplicity from a prokaryote would be a fundamental misunderstanding of what “acellular” means [1].

10. The cell is likely from an animal, or from any other non-photosynthesising cell (for example a fungal cell, or a non-photosynthesising plant cell such as a root cell) [1], because it has mitochondria for aerobic respiration but lacks chloroplasts, which are only found in plant and algal cells that carry out photosynthesis; the absence of a cell wall or a permanent vacuole would confirm an animal cell specifically [1].

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Where marks are usually lost

• Describing an organelle without linking its structure to its function — mark schemes reward the link, not just a description of either alone.
• Saying bacteria and plant cells “both have a cell wall” without naming the different materials (murein vs cellulose).
• Confusing a virus’s small size with being a “simple cell” — acellular means not a cell at all, not simply a minimal one.
• Forgetting that prokaryotic DNA is not associated with protein, unlike the protein-bound linear DNA in a eukaryotic nucleus.
• Naming lysosomes as generic “digestive organelles” without specifying that they contain hydrolytic enzymes and fuse with vesicles to release them.

Approaching structure-function questions

Whenever a question asks how an organelle’s structure relates to its function, the highest-scoring answers follow a consistent three-part pattern: state the relevant structural feature precisely (not just the organelle’s name), state the function, and then explicitly explain the mechanical or chemical link between them — for example, that folded membranes increase surface area, or that a fluid-filled compartment allows enzymes to be concentrated together. Naming the organelle and its function separately, without the explicit “because” that connects them, is the most common way full marks are missed on this sub-topic.