Question 6 from UPSC CSE 2016 - Science and
Technology

Question

Which of the following statements is/are correct? Viruses can infect:
1. bacteria
2. fungi
3. plants
Select the correct answer using the code given below.

IASCODEX · Accepted Answer

Correct Option: D. 1, 2, and 3

Strategy: Confirm the accuracy of each statement by recalling the types of viruses that infect bacteria (bacteriophages), fungi (mycoviruses), and plants. As all three statements are correct, the correct choice is D.

Key Info: Viruses are acellular, obligate intracellular parasites, meaning they lack cellular machinery and must infect a host cell to replicate. Their genetic material (DNA or RNA) is encapsulated within a protein coat (capsid). They exhibit a remarkable diversity in host range, infecting organisms across all domains of life.

*   **Bacteriophages:** These are viruses that specifically infect bacteria. They are among the most abundant biological entities on Earth and play a crucial role in microbial ecology. A well-known example is the T4 bacteriophage, which infects *Escherichia coli*.
*   **Mycoviruses:** These are viruses that infect fungi. Unlike many other viruses, a significant proportion of mycoviruses possess double-stranded RNA (dsRNA) genomes. They can influence fungal pathogenicity, growth, and development, sometimes without causing obvious symptoms in their fungal hosts.
*   **Plant Viruses:** Numerous viruses are known to infect plants, causing a wide range of diseases that can significantly impact agricultural yields. Examples include Tobacco Mosaic Virus (TMV), potato virus Y, and cucumber mosaic virus. Plant viruses are typically transmitted by insect vectors, nematodes, or through mechanical damage.

IASCODEX · Answer

Option A: 1 and 2 only

IASCODEX · Answer

Option B: 3 only

IASCODEX · Answer

Option C: 1 and 3 only

Which of the following statements is/are correct? Viruses can infect: bacteria fungi plants Select the correct answer using the code given below.

Which of the following statements is/are correct? Viruses can infect:

bacteria

fungi

plants
Select the correct answer using the code given below.