Microbiology is the study of microbes. Which of the following is considered a microbe? Select one or more: a. bacteria b. viroids c. prions d. archaea e. protists
The correct answer and explanation is:
Correct Answers:
✅ a. Bacteria
✅ b. Viroids
✅ c. Prions
✅ d. Archaea
✅ e. Protists
Explanation (300 words):
Microbiology is the branch of science that studies microbes — organisms and infectious agents that are too small to be seen with the naked eye. This includes a wide variety of living and non-living entities, such as bacteria, viruses, fungi, protozoa, prions, and viroids.
Let’s break down each option:
a. Bacteria
✅ Microbe – Bacteria are unicellular prokaryotic organisms. They are among the most commonly studied microbes in microbiology. Some are harmless or even beneficial, while others can cause disease.
b. Viroids
✅ Microbe – Viroids are infectious agents made up of a short strand of circular RNA without a protein coat. They are smaller than viruses and typically infect plants. Despite their simplicity, they are studied in microbiology due to their pathogenic effects.
c. Prions
✅ Microbe – Prions are infectious proteins that cause neurodegenerative diseases, such as Creutzfeldt-Jakob disease and mad cow disease. Though they lack nucleic acids (DNA or RNA), they are included in microbiology because they cause disease and are microscopic.
d. Archaea
✅ Microbe – Archaea are prokaryotic cells like bacteria but differ in genetics and membrane composition. They often live in extreme environments, such as hot springs or salt lakes, and are considered microbes.
e. Protists
✅ Microbe – Protists are mostly unicellular eukaryotes (like amoebas and paramecia). Some are photosynthetic, while others are heterotrophic. Many are studied in microbiology, especially those that cause diseases (e.g., Plasmodium, which causes malaria).
Conclusion:
All the listed options — bacteria, viroids, prions, archaea, and protists — are considered microbes because they are microscopic and fall under the study of microbiology.