MCQs on Prions

A prion is a protein that causes disease in both animals and humans by causing normally healthy proteins in the brain to fold abnormally. Because prion proteins are simply proteins without any genetic material, their mode of action is very different from that of bacteria and viruses. Prions are thought to be the cause of transmissible spongiform encephalopathies, or prion diseases, which are a group of rapidly progressive neurodegenerative diseases. They are infectious isoforms of the prion protein, a host-encoded cellular protein. A prion is a protein that causes disease in both animals and humans by causing normally healthy proteins in the brain to fold abnormally. Because prion proteins are simply proteins without any genetic material, their mode of action is very different from that of bacteria and viruses.

Question 1: Retroviruses and reverse transcriptase were discovered by

1. A) Sinsheimer
2. B) Stanley
3. C) Temin and Baltimore
4. D) Hershey and Chase

Answer : C

Explanation: 

David Baltimore and Howard Temin independently discovered reverse transcriptase in retroviruses (then RNA tumour viruses) in 1970, revolutionising molecular biology and laying the groundwork for retrovirology and cancer biology.

Question 2 : Single stranded DNA as genetic material in ɸ x 174 was discovered by

1. A) Delbruck
2. B) Saffarman and Morris
3. C) Reed and Findley
4. D) Sinsheimer

Answer : D

Explanation:

The bacteriophage phi X 174 (or X174) is a single-stranded DNA (ssDNA) virus that infects Escherichia coli and was the first DNA-based genome to be sequenced. Fred Sanger and his team finished this project in 1977.

Question 3 : TMV is 

1. A) Helical Virus
2. B) Polyhedral Virus
3. C) Spherical Virus
4. D) Binal Virus

Answer : A

Explanation:

Tobacco mosaic virus is a positive-sense single-stranded RNA virus that infects a wide variety of plants, particularly tobacco and other members of the Solanaceae family.

Question 4 : Smallest virus is

1. A) Foot and Mouth virus
2. B) Alfalfa Mosaic virus
3. C) Pseudomonas Pf
4. D) TMV

Answer : A

Single-stranded DNA (ssDNA) viruses are the smallest viruses in terms of genome size. The bacteriophage Phi-X174, which has a genome size of 5386 nucleotides, is perhaps the most well-known. Some ssDNA viruses, on the other hand, can be even smaller.

Question 5 : Who discovered virus to be a nucleoprotein entity?

1. A) Causius
2. B) Pasteur
3. C) Ivanowski
4. D) Bawden and Pirie

Answer : D

Question 6 : Name the most common viral disease

1. A) Flu
2. B) Common Cold
3. C) Rabies
4. D) Chicken Pox

Answer : B

Question 7 : The term virus was coined by 

1. A) Ivanowski
2. B) Beijerink
3. C) Pasteur
4. D) Loeffler and Frosch

Answer : C

Explanation:

The name virus was coined by Martinus Willem Beijerinck.

Question 8 : A viral disease known from prehistoric times is

1. A) Pneumonia
2. B) Smallpox
3. C) Poliomyelitis
4. D) Both B and C

Answer : D

Question 9 : Rabies or hydrophobia is a disease

1. A) Viral
2. B) Bacterial
3. C) Protozoan
4. D) Helmintic

Answer : A

Question 10 : Who discovered vaccination against smallpox?

1. A) Jenner
2. B) Pasteur
3. C) Lister
4. D) Mayer

Answer : A

Question 11 : Extract of Tobacco with Mosaic disease was called contagium vivum fluidum by 

1. A) Mayer
2. B) Ivanowski
3. C) Beijerink
4. D) Pasteur

Answer : C

Question 12 : Who found poliomyelitis to be a viral disease?

1. A) Pasteur
2. B) Popper
3. C) De Herelle
4. D) Loeffler and Frosch

Answer : B

Question 13 : bacteriophages were discovered by

1. A) Twort
2. B) De Herelle
3. C) Takahashi and Rawlins
4. D) Stanley

Answer : A

Question 14 : The term bacteriophage was coined by 

1. A) Pasteur
2. B) Ivanowski
3. C) Saffarman and Morris
4. D) De Herelle

Answer : D

Question 15 : Name the virus which was crystallized for the first time.

1. A) Parrot Fever Virus
2. B) Small Pox Virus
3. C) TMV
4. D) HIV

Answer : C

Question 16 : Who cultured the virus for the first time?

1. A) Stanley
2. B) Enders
3. C) Takahashi and Rawlins
4. D) Issacs and Lindermann

Answer : B

Question 17 : The first virus to be cultured in human cells was

1. A) Polio Virus
2. B) Dengue Virus
3. C) Influenza Virus
4. D) HIV

Answer : A

Explanation:

In 1941, John Enders, Frederick Robbins, and Thomas Weller were successful in culturing the poliovirus. In a lab setting, they cultured the poliovirus in human muscle and tissue. The first virus to be cultured in human cells was this one.

Question 18 : Coliphages are viruses parasitising

1. A) Fungi
2. B) Alimentary canal
3. C) Escherichia coli
4. D) Yeast

Answer : C

Explanation:

Coliphages are bacteriophages that attack and parasitize Escherichia coli bacterial cells. Coliphage T2T2 is an Escherichia coli lytic phage. An icosahedral proteinaceous head, collar, and tail make up the structure. As genetic material, the head contains dsDNA. It is made up of two strands that are complementary to each other.

As a result, option ‘Escherichia coli’ is the correct answer.

Question 19 : Who discovered that RNA is genetic material in TMV?

1. A) Gierere and Schramm
2. B) Issacs and Lindermann
3. C) Sinsheimer
4. D) Delbruck

Answer : A

Explanation:

The discovery of the genetic functions of RNA in a plant virus (Tobacco mosaic virus, TMV) is widely credited to American plant virologist Heinz Fraenkel-Conrat, as well as Germans Alfred Gierer and Gerhard Schramm, who independently arrived at the same conclusion in 1956.

Question 20 : The most mutable virus is

1. A) Chicken Pox Virus
2. B) HIV
3. C) Influenza Virus
4. D) Dengue Virus

Answer : B

Explanation: HIV Virus is the most mutable form of virus. 

Question 24 : Bacteriophage T2 is

1. A) Filamentous
2. B) Cuboidal
3. C) Binal
4. D) Spherical

Answer : C

The T2 phage belongs to a common phage family. T2 phage is a type of cellular phage. A protein shell surrounds the body, which is divided into two parts: head and tail. The head is hexagonal, and the tail is rod-shaped. A’ double-strand DNA in its head is found inside the shell.

Question 25 : Which is absent in virus?

1. A) Genetic material
2. B) Protein cover
3. C) Protoplasm
4. D) Both A and B.

Answer : C

Explanation:

The virus lacks protoplasm. As a result, the correct response is ‘protoplasm.’