FSc Part 1 Biology chapter 6: Kingdom Prokaryotae MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

21 exam-style questions on Kingdom Prokaryotae, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

21 questions · 2 topics · 10 per test

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What chapter 6 covers

Ten Kingdom Prokaryotae questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. A bacterium is grown in a tube of nutrient broth. It grows throughout the tube but the growth is densest near the top. It is most likely a

  1. A
    obligate aerobe
  2. B
    facultative anaerobe
  3. C
    obligate anaerobe
  4. D
    microaerophilic bacterium
Show answer

Answer: B. Growth throughout the tube shows it can live without oxygen, and denser growth at the top shows it grows better with oxygen: a facultative anaerobe. An obligate aerobe would grow only at the top, and an obligate anaerobe only at the bottom.

2. Penicillin, the first antibiotic, was discovered by

  1. A
    Louis Pasteur
  2. B
    Alexander Fleming
  3. C
    Robert Koch
  4. D
    Joseph Lister
Show answer

Answer: B. Fleming (1928) noticed that the mould Penicillium killed bacteria around it on a culture plate.

3. Cyanobacteria differ from other photosynthetic bacteria because they

  1. A
    contain chlorophyll a and release oxygen in photosynthesis
  2. B
    contain bacteriochlorophyll and release sulphur in photosynthesis
  3. C
    have a true nucleus surrounded by a nuclear envelope
  4. D
    have chloroplasts with grana and a double membrane
Show answer

Answer: A. Cyanobacteria have chlorophyll a like plants and release oxygen, but they are prokaryotes without chloroplasts.

4. Bacteria were first observed through his simple microscope by

  1. A
    Robert Hooke
  2. B
    Leeuwenhoek
  3. C
    Louis Pasteur
  4. D
    Robert Koch
Show answer

Answer: B. Antonie van Leeuwenhoek described bacteria ("animalcules") in 1676. Koch later linked particular bacteria to particular diseases.

5. A soil bacterium grows in the dark in a purely mineral medium whose only nutrients are ammonium ions and carbon dioxide. It gains energy by oxidising the ammonium ions. It is a

  1. A
    parasite
  2. B
    photoautotroph
  3. C
    saprotroph
  4. D
    chemoautotroph
Show answer

Answer: D. It makes its own organic food from CO2 (autotroph) using energy from oxidising an inorganic chemical (chemo-), as nitrifying bacteria do. A photoautotroph would need light, and saprotrophs and parasites need organic food.

6. Short, hair-like protein appendages that attach bacteria to surfaces and help in conjugation are

  1. A
    flagella
  2. B
    mesosomes
  3. C
    pili
  4. D
    capsules
Show answer

Answer: C. Pili (fimbriae) are for attachment and, as sex pili, for conjugation. Flagella are longer and used for movement.

7. Purple and green sulphur bacteria make food using light but do not release oxygen because they

  1. A
    carry out photosynthesis only during the night
  2. B
    contain no pigment to absorb the light
  3. C
    use glucose as their only source of energy
  4. D
    split H2S, not water, to obtain hydrogen
Show answer

Answer: D. These bacteria split H2S, releasing sulphur instead of oxygen. Oxygen comes from splitting water in plants and cyanobacteria.

8. After Gram staining and washing with alcohol, a smear of bacteria appears pink under the microscope. The best explanation is that the cells have

  1. A
    a thin peptidoglycan wall and an outer membrane, so the crystal violet was washed out
  2. B
    a thick peptidoglycan wall that held the crystal violet inside the cells
  3. C
    no cell wall, so the dye could not bind to them at all
  4. D
    a cellulose wall that took up only the pink counterstain
Show answer

Answer: A. Gram-negative cells have a thin peptidoglycan layer and an outer lipid membrane, so alcohol removes the crystal violet and they take up the pink counterstain. Gram-positive cells with thick walls stay purple.

9. Griffith's experiment, in which harmless bacteria became virulent after being mixed with heat-killed virulent bacteria, demonstrated

  1. A
    conjugation
  2. B
    transformation
  3. C
    transduction
  4. D
    mutation by heat
Show answer

Answer: B. The living harmless cells took up DNA released from the dead virulent cells: transformation.

10. In Nostoc, nitrogen fixation takes place in special thick-walled cells called

  1. A
    akinetes
  2. B
    heterocysts
  3. C
    hormogonia
  4. D
    endospores
Show answer

Answer: B. Heterocysts lack oxygen-producing photosystem II, protecting the nitrogen-fixing enzyme from oxygen. Akinetes are resting spores; hormogonia are fragments for reproduction.

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Ways to practise this chapter

Kingdom Prokaryotae: questions students ask

How many Kingdom Prokaryotae MCQs are there?

21, each with the answer and a short explanation, across 2 topics: Structure, forms and nutrition of bacteria, Growth, reproduction, importance and control of bacteria; cyanobacteria. Every chapter test draws ten of them, so you can take it many times.

Is the FSc Part 1 Biology chapter 6 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

Can I read the explanations in Urdu?

Yes. In practice mode and on your results you can switch the explanations to Urdu.

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