Lesson 3.1.4

3.1.4 Prokaryotic cell ultrastructure Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.1.4, Prokaryotic cell ultrastructure: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 3: Voice of the Genome, written with Revision Ninja.

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The 20 questions

  1. Where is the DNA found in a bacterial cell?

    • In the mitochondria only
    • In a nucleoid region that is not enclosed by a membrane
    • In the chloroplasts only
    • Inside a membrane-bound nucleus

  2. Which structure is a small circular piece of DNA found in bacteria?

    • Mesosome
    • Pilus
    • Plasmid
    • Flagellum

  3. Which bacterial structure is used for movement?

    • Capsule
    • Pilus
    • Plasmid
    • Flagellum

  4. What is the function of pili in bacteria?

    • Attachment to surfaces and transfer of genetic material between bacteria
    • Storage of water for osmoregulation
    • Photosynthesis in the cell membrane
    • Propulsion through liquid environments

  5. What is the main chemical component of bacterial cell walls?

    • Peptidoglycan
    • Lignin
    • Chitin
    • Cellulose

  6. What is the capsule of a bacterium?

    • The region where proteins are assembled from amino acids
    • A slimy outer layer that can protect the cell, including
    • The site of aerobic respiration in the cell
    • The region of the cell that contains the DNA

  7. What is the typical diameter of a bacterial cell?

    • About 0.5 to 2 um
    • About 50 mm
    • About 100 um
    • About 1 nm

  8. A bacterium 2 um long is viewed in an image at a magnification of x10,000. What is its length in the image?

    • 20 mm
    • 2 mm
    • 0.2 mm
    • 200 mm

  9. An antibiotic binds to 70S ribosomes and blocks their function in bacteria. Which process is inhibited?

    • Photosynthesis
    • Mitosis
    • Protein synthesis
    • DNA replication in the nucleus

  10. Why are plasmids useful in genetic engineering?

    • They can carry genes and replicate independently of the main chromosome
    • They are used to build mitochondria
    • They produce the bacterial cell wall
    • They contain the cell's entire genome

  11. Which statement about ribosomes is correct?

    • Prokaryotic ribosomes are 80S, which are larger than eukaryotic ribosomes
    • Prokaryotic ribosomes are 70S, which are smaller than the 80S ribosomes of eukaryotes
    • Eukaryotic ribosomes are found only in the nucleus
    • Both types are 70S, but eukaryotic ribosomes are membrane-bound

  12. What are mesosomes thought to be in bacteria?

    • Infoldings of the plasma membrane that may be involved in respiration or DNA separation
    • Structures that synthesise glycogen
    • Sites where lysosomes are produced
    • Capsules that store carbohydrate

  13. Why are antibiotics that target bacterial cell walls ineffective against viruses?

    • Viruses lack a cell wall and are not prokaryotic cells
    • Viruses have many nuclei that resist antibiotics
    • Viruses contain chloroplasts that repel the drug
    • Viruses have 80S ribosomes that the drug cannot reach

  14. A bacterial mutant loses its flagella. Which change in behaviour is most likely?

    • Its DNA is no longer replicated
    • It can no longer make proteins
    • It can no longer swim towards nutrients using flagellar movement
    • It stops dividing by binary fission

  15. What is binary fission?

    • Sexual reproduction by the fusion of two gametes
    • Asexual reproduction in which the bacterial DNA is copied and the cell divides into two
    • Formation of spores by meiosis
    • Mitosis in multicellular organisms

  16. In the term 70S, what does 'S' represent?

    • The sedimentation coefficient, a measure of how fast a particle sediments in a centrifuge
    • The length of the molecule in nanometres
    • The number of ribosomal subunits in the complex
    • The mass of the molecule in daltons

  17. Which statement compares prokaryotic and eukaryotic DNA correctly?

    • Prokaryotic DNA is usually circular and is not packaged with histones in the same way as eukaryotic DNA
    • Prokaryotic DNA is linear and wrapped around histones in chromosomes
    • Both have DNA in a nucleus of similar structure
    • Eukaryotic DNA is circular and found freely in the cytoplasm

  18. A bacterium has a capsule, a mesosome and a nucleoid. Which of these lies outside the plasma membrane?

    • Nucleoid
    • Ribosome
    • Capsule
    • Mesosome

  19. Which structure controls the movement of substances into and out of a bacterial cell?

    • The capsule
    • The plasmid
    • The plasma membrane
    • The pilus

  20. A spherical bacterium has a radius of 0.5 um. What is its surface area to volume ratio?

    • 6 per um
    • 12 per um
    • 3 per um
    • 0.5 per um

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