Class 12 Biology MCQ – Viral Diseases in Humans-1


This set of Class 12 Biology Chapter 8 Multiple Choice Questions & Answers (MCQs) focuses on “Viral Diseases in Humans-1”.

1. Which virus causes Small Pox disease?
a) Variola virus
b) Varicella zoster
c) Rubeola virus
d) Rhabdo virus
View Answer

Answer: a
Explanation: Variola virus causes Small Pox disease. Varicella zoster, Rubeola and Rhabdo viruses cause Chicken Pox, Measles and Rabies respectively.

2. Variola virus has ________ as genetic material.
a) Single stranded RNA
b) Double stranded RNA
c) Single stranded DNA
d) Double stranded DNA
View Answer

Answer: d
Explanation: Variola virus has double stranded DNA as genetic material. Plant viruses generally have Single stranded RNA as a genetic material. Animal viruses have Single stranded or Double stranded RNA or Double stranded DNA as genetic material. Bacteriophages have Double stranded DNA as genetic material.

3. Small Pox vaccine is which kind of vaccine?
a) Attenuated Vaccine
b) Inactivated Vaccine
c) Second Generation Vaccine
d) Third Generation Vaccine
View Answer

Answer: a
Explanation: Small Pox vaccine is an Attenuated Vaccine. Attenuated Vaccines are made by weakening the virulent properties of the pathogen. These vaccines provide Artificial Active Immunity and vaccination is the best preventive remedy for Small Pox.
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4. Who is known as the Father of Immunology?
a) Dmitry Ivanovsky
b) Edward Jenner
c) Erik Acharius
d) Francesco Redi
View Answer

Answer: b
Explanation: Edward Jenner is the Father of Immunology. He discovered the Small Pox vaccine in 1796. Dmitry Ivanovsky is known as the Father of Virology. Erik Acharius is the Father of Lichenology. Francesco Redi is the Father of Parasitology.

5. When was Small Pox eradicated from the world?
a) 1971
b) 1977
c) 1967
d) 1980
View Answer

Answer: d
Explanation: The last known case of Small Pox was in 1977. However, the world was declared Small Pox free in 1980 by the World Health Organisation.
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6. In Chicken Pox, rashes first appear on the body and then on the face.
a) True
b) False
View Answer

Answer: a
Explanation: Rashes first appear on the body and then on the face in Chicken Pox disease. The rash comes out in crop and with each fresh crop, there may be slight fever again. Rashes change into Papules-vesicles without fluid and then into pustules and finally into a dark brown scab which falls off leaving no scar.

7. Which of the following is the most common late complication of Chicken Pox?
a) Fever
b) Shingles
c) Small Pox
d) Mumps
View Answer

Answer: b
Explanation: The most common late complication of Chicken Pox is Shingles which is caused by the reactivation of Varicella zoster virus. Shingles cause the appearance of painful rashes which appear as a stripe of blisters on the trunk or the back.

8. What is the full form of MMR vaccine?
a) Mumps Measles Rabies
b) Malignant Melanoma Rheumatism
c) Measles Mumps Rubella
d) Malignant-Malaria Rheumatoid
View Answer

Answer: c
Explanation: MMR Vaccine is a combined vaccine given to babies within 12-15 months of their birth for the protection against Measles, Mumps and Rubella viruses.

9. What is the incubation period of Rhabdo virus?
a) 1 day-2 weeks
b) 10-20 days
c) 2-4 weeks
d) 10 days-1 year
View Answer

Answer: d
Explanation: Rhabdo virus is introduced in the body by the bite of rabid or mad dogs usually. It can also be injected by the bite of cats, wolves etc. The incubation period of this virus is from 10 days to one year.

10. Which is the most important characteristic symptom of Rabies?
a) Fear of Height
b) Fear of Water
c) Fear of Cats
d) Fear of Fire
View Answer

Answer: b
Explanation: Rabies is commonly called as hydrophobia which means Fear of Water. Therefore, Fear of Water is the most important characteristic symptom of Rabies. Other symptoms include excess salivation, severe headache, alternating phases of excitement and depression.

11. What is the mortality rate of humans if they contract rabies?
a) 50% fatal
b) 100% fatal
c) No effects
d) 33% fatal
View Answer

Answer: b
Explanation: Rabies is 100% fatal if neurological symptoms have developed like violent movements, uncontrolled excitement, inability to move the parts of the body, confusion and loss of consciousness. Once these symptoms appear, the result is always death.

12. What is the earliest sign of contracting Polio?
a) Paralysis
b) Inflammation of the body
c) Inability to bend the head forward
d) Inability to walk
View Answer

Answer: c
Explanation: The earliest sign of Polio is the inability to bend the head forward. However, the attack of paralysis begins with high fever, headache, chills, vomiting and pain all over the body. Within 2-3 days the paralysis reaches its maximum.

13. Which of the following options is incorrect regarding the contraction of Polio?
a) It spreads through intestinal discharges
b) It spreads through contaminated food and water
c) It spreads by flies
d) It spreads through mosquito bites
View Answer

Answer: d
Explanation: Polio disease mainly spreads through intestinal discharges like the faeces. It may also spread through contaminated food or water and by flies or other insects which contaminate food or drink. Poliovirus usually enters the body through the alimentary canal where it multiplies and then reaches the nervous system via bloodstream.

14. What is the full form of OPV?
a) Oral Polio Vaccine
b) Oesophagus Polio Vaccine
c) Oral Plague Vaccine
d) Oesophagus Plague Vaccine
View Answer

Answer: a
Explanation: The full form of OPV is the Oral Polio Vaccine. The Oral Polio Vaccine was developed by Albert Sabin and came into commercial use in 1961.

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