Free Viruses MCQs with Answers
247 Viruses MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Viruses are acellular infectious particles made of genetic material enclosed by a protein capsid, sometimes with a lipid envelope. Their replication depends on a host cell and may follow lytic or lysogenic cycles, so viral structure and reproduction differ fundamentally from those of cellular organisms such as bacteria.
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247 questions · page 8 of 13
- A. Lytic phages
- B. Virulent phages
- C. Temprate phages
- D. None of these options is correct
Explanation: Option A; virulent bacteriophages, which immediately produce progeny and lyse the host cell.Option B: lytic phage is virulent phageOption…
Correct answer: Temprate phages- A. DNA enveloped virus
- B. RNA enveloped virus
- C. DNA virus
- D. Naked virus
Explanation: Option B is orrect. Option B is correct. a family of single-stranded RNA viruses.
Correct answer: RNA enveloped virus- A. Influenza
- B. Smallpox
- C. Mumps and measles
- D. AIDS
Explanation: Paramyxoviruses are a group of viruses that cause diseases such as mumps and measles. All the other options are incorrect.
Correct answer: Mumps and measles- A. Herpes virus
- B. Reovirus
- C. Polio virus
- D. Papillomavirus
Explanation: Among all of the above options, only herpes is an enveloped virus. All the rest are non-enveloped.
Correct answer: Herpes virus- A. genome and capsid
- B. capsid and spikes
- C. envelope and capsid
- D. capsomeres and genome
Explanation: FACTUAL RECALLThe virions are composed of a central core of nucleic acid, either DNA or RNA, which is also known as the genome and is…
Correct answer: genome and capsid- A. Icosahedral virus
- B. Naked virus
- C. Enveloped virus
- D. Bilayer virus
Explanation: a. Icosahedral virus: Icosahedral viruses have a symmetrical structure that resembles a 20-sided polyhedron.
Correct answer: Naked virus- A. It is an individual unit of the capsid
- B. It is a viral protein for replication
- C. It is a unit of nucleic acid in viruses
- D. All of the above
Explanation: Capsomeres are tiny subunits that make up the protein coat, referred to as the capsid.
Correct answer: It is an individual unit of the capsid148. In what year did the World Health Organization declare that smallpox was completely eradicated?
- A. 1990
- B. 1980
- C. 2001
- D. 1995
Explanation: Almost two centuries after Jenner hoped that vaccination could annihilate smallpox, the 33rd World Health Assembly declared the world free…
Correct answer: 1980- A. Bacteriophages
- B. Animal viruses
- C. Plant viruses
- D. Fungal viruses
Explanation: Bacteriophages are viruses that infect bacteria. They produce the enzyme lysozyme, which causes the host bacterial cell to burst and die…
Correct answer: Bacteriophages- A. 100mm to 150mm
- B. 20nm to 250nm
- C. 300nm to 3000nm
- D. 3nm to 30nm
Explanation: Viruses are pathogens, which cause diseases in animals and plants.The size of a virus ranges between 20nm-250nm in length.Hence, B is the…
Correct answer: 20nm to 250nm- A. Hexagonal capsomeres
- B. Pentagonal capsomeres
- C. Triangular Capsomeres
- D. Both options A and B are correct
Explanation: Capsid: The coat is the outer covering of a viral particle which consists of a capsid and envelope.
Correct answer: Both options A and B are correct- A. HSV-2
- B. Varicella-zosster virus
- C. Oncovirus
- D. Picornavirus
Explanation: An oncovirus or oncogenic virus is a virus that can cause cancer. Hence, C is the correct option.
Correct answer: Oncovirus- A. 250
- B. 200
- C. 150
- D. 100
Explanation: Option B is correct as there is are 200 bacteriophages produced after 25 minutes of initial infection.
Correct answer: 200- A. The mitochondrion of the cell
- B. Cell membrane of host cell
- C. Endoplasmic reticulum of the cell
- D. None of these
Explanation: Correct option is B. The outermost layer of a virus is the envelope. A large number of viruses do not have envelopes.
Correct answer: Cell membrane of host cell- A. Lytic phage
- B. Lysogenic phage
- C. Prophage
- D. Bacteriophage
Explanation: Option A : The phage which causes lysis of host cells is known as lytic or virulent phage.
Correct answer: Lysogenic phage- A. Self replication in host cell
- B. Duplication
- C. Self duplication
- D. Multiplication in host cell
Explanation: Option: A Bacteriophages have been widely used in genetic research because they can easily replicate inside host cells.
Correct answer: Self replication in host cell- A. Bacteria
- B. Viruses
- C. Fungi
- D. Both A and B
Explanation: According to Ivanovski, the term "soluble living germs" refers to the infectious agent responsible for causing the disease tobacco mosaic…
Correct answer: Viruses- A. Injecting DNA
- B. Replication
- C. Dissolve bacterial cell wall
- D. All of these
Explanation: The lysozyme enzyme is a digestive enzyme that 'digests the bacterial cell wall'.
Correct answer: Dissolve bacterial cell wall- A. HIV
- B. Poxviruses
- C. Covid-19
- D. HBV
Explanation: The poxviruses are the largest known DNA viruses and are distinguished from other viruses by their ability to replicate entirely in the…
Correct answer: Poxviruses- A. Virulent phage
- B. Lytic phage
- C. Temperate phage
- D. Both A and B
Explanation: The correct statement is that the phage causing the lysogenic cycle is a "Temperate Phage." Temperate phages can enter the lysogenic…
Correct answer: Temperate phage