Prokaryotic Cells: The Simplest Form of Cellular Life
Prokaryotic cells are the oldest, simplest, and most abundant cells on Earth. Found in bacteria and archaea, they carry out every essential life process without a well-defined nucleus or membrane-bound organelles.
This quiz follows Lesson 4: Prokaryotic Cells and tests your grasp of:
- The organisms that prokaryotic cells represent
- Typical size and the four characteristic shapes (bacillus, coccus, vibrio, spirillum)
- Naked genetic material and the absence of a nuclear membrane
- Plasmids and their role in antibiotic resistance
- The mesosome as an infolding of the plasma membrane
- Ribosomes and inclusion bodies in prokaryotic cytoplasm
Work carefully through each question — the distractors are designed to test precise understanding, not guesswork. Good luck!
Q1. Which group of organisms is represented by prokaryotic cells?
Prokaryotic cells are the cellular form found in bacteria and archaea, and they constitute the vast majority of living organisms by number and biomass.
Q2. A typical prokaryotic cell measures approximately:
Typical bacteria measure about 1 to 2 micrometres, while viruses are 0.02 to 0.2 micrometres and a typical eukaryotic cell is 10 to 20 micrometres.
Q3. The term "prokaryote" is derived from Greek words meaning:
Pro means before and karyon means nucleus, so a prokaryote is literally a cell that exists before the nucleus, or more precisely, without one.
Q4. In prokaryotes, the genetic material is described as "naked" because it is:
The genetic material is basically naked, meaning it is not enveloped by a nuclear membrane; it lies free in the cytoplasm.
Q5. Which statement about the cell wall of prokaryotes is correct?
Prokaryotes have a cell wall surrounding the cell membrane except in mycoplasma, which lacks a cell wall.
Q6. The small circular DNA molecules found outside the genomic DNA in many bacteria are called:
In addition to the genomic DNA (the single circular chromosome), many bacteria have small circular DNA outside it, called plasmids.
Q7. Plasmid DNA confers which of the following unique phenotypic characters to bacteria?
The plasmid DNA confers certain unique phenotypic characters, one of which is resistance to antibiotics.
Q8. Which organelles of eukaryotic cells are found in prokaryotic cells?
No organelles like those in eukaryotes are found in prokaryotic cells except for ribosomes.
Q9. The mesosome, characteristic of prokaryotes, is essentially:
A specialised differentiated form of cell membrane called the mesosome is characteristic of prokaryotes; it is essentially an infolding of the cell membrane.
Q10. The semi-fluid matrix that fills the prokaryotic cell is called the:
The semi-fluid matrix filling the cell is the cytoplasm, in which the naked DNA lies free.
Q11. Which of the following is NOT a function of the mesosome?
Mesosomes help in cell wall formation, DNA replication and distribution, respiration and secretion; a nuclear envelope is a eukaryotic feature absent in prokaryotes.
Q12. The extensions of the plasma membrane that form the mesosome may take the shape of:
The mesosome extensions are in the form of vesicles, tubules and lamellae, which increase the surface area of the plasma membrane.
Q13. Reserve material in prokaryotic cells is stored in the cytoplasm as inclusion bodies, which are:
Inclusion bodies such as phosphate granules, cyanophycean granules and glycogen granules are not bound by any membrane system and lie free in the cytoplasm.
Q14. Prokaryotic ribosomes are made of two subunits of which sizes?
Prokaryotic ribosomes are made of two subunits, the 50S and 30S units, which when present together form the 70S prokaryotic ribosome.
Q15. Which feature best explains why prokaryotes are considered structurally distinct from eukaryotes?
The fundamental distinction is that prokaryotes have no well-defined nucleus and no membrane-bound organelles except ribosomes, unlike eukaryotes with their organised nucleus and compartmentalised cytoplasm.