This set of Biology Multiple Choice Questions & Answers (MCQs) focuses on “Biological Classification – Viruses, Viroids and Lichens – 1”.
1. Viruses are living organisms.
Explanation: Viruses are non-living organisms. They don’t have cell. They don’t reproduce or perform any metabolic activities when they are outside a living host. When they are inside a living host they do reproduce and multiply in numbers.
2. Viruses in animals contain both RNA and DNA.
Explanation: Viruses at any cost don’t contain both RNA and DNA. Animal viruses contain either single/double stranded ribonucleic acid or double stranded deoxy ribonucleic acid.
3. Viruses that infect bacterium are called as _________
b) Viral bacterium
Explanation: Viruses are smaller when compared to bacterium. Viruses can infect bacterium are called bacteriophages. Bacteriophages contain double stranded DNA (Deoxy ribonucleic acid).
4. Viruses that infect plants have ________
a) single stranded RNA
b) double stranded RNA
c) single stranded DNA
d) double stranded DNA
Explanation: Viruses that infect plants called as plant viruses have single stranded RNA. Animal viruses contain a single/ double stranded RNA or a double stranded DNA. Bacteriophages have double stranded DNA.
5. The word “Virus” means ______
Explanation: The word “Virus” refers to venom or poisonous. It was first termed by a Dutch microbiologist named Martinus Beijerinck in 20th century. Dmitri Ivanowsky discovered viruses for the first time.
6. Why are viruses not included in any of the five kingdoms?
a) There are already more than thousands of organisms in the five kingdoms and hence, no space to include viruses
b) Viruses are not living organisms
c) Viruses reproduce rapidly which is in fact weird and therefore they are not classified under any of the five kingdoms
d) Viruses are so small that they can’t be studied
Explanation: Unlike organisms in the other five kingdoms which are living, viruses are non-living organisms. They don’t even have basic unit of life i.e. cell. Hence, they are not categorized in any of the kingdoms.
7. Which among the following are incorrect about Viruses?
a) Viruses are acellular
b) Viruses are smaller than bacterium
c) Viruses can perform all of their metabolic activities except reproduction when outside a living host
d) Viruses are non-living organisms
Explanation: Viruses can’t perform any of the metabolic activities when outside a living host. So, they are non-living organisms. Viruses don’t even consist of a cell and so acellular. They are in fact smaller than that of a bacterium and can even infect them.
8. Viruses contain sheath made of ______
a) Nucleic acids
Explanation: Viruses don’t contain cell and instead have genetic material made of nucleic acids and a protein sheath covering it which is made of proteins. This protein sheath is called capsid and is made of basic units called as capsomeres.
9. Who proved that viruses are crystalline like structures?
a) W M Stanley
c) M W Beijerinek
Explanation: Ivanowsky discovered viruses as micro-organisms on tobacco plant and are smaller than bacterium. Later M W Beijerinek termed them as “Viruses” which means venom or poison. W M Stanley for the first time proved that viruses are crystalline like structures and these crystals are made of protein rich sheaths.
10. Viruses are an example of ________
a) Obligate parasites
b) Facultative parasites
Explanation: Viruses are an example of obligate parasites. Viruses can’t perform any of their metabolic activities when they are outside a living host. As soon as they enter a living host they replicate and perform their metabolic activities. Therefore, they are an example of obligate parasites.
Sanfoundry Global Education & Learning Series – Biology – Class 11.
To practice all areas of Biology, here is complete set of 1000+ Multiple Choice Questions and Answers.
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