1. The critical component in the SOS response is ______________
a) Lex A
b) Rec A
c) Rec B
d) Lex B
Explanation: The critical component in the SOS response is the Rec A protein. The main function of the Rec A protein is to mediate the recombination between DNA molecules. In the condition of stress, the Rec A protein alters its activity to become a specific protease.
2. LATs are _____________
a) introns
b) proteins
c) exons
d) fatty acids
Explanation: LATs are latency-associated transcripts which are stable introns, produced by splicing of longer RNAs, and they do not encode proteins. The cells expressing LATs suppress the production of immediate early mRNAs.
3. The delayed infection of EBV causes _____________
a) glandular fever
b) swelling
c) pain
d) lesions
Explanation: Epstein-Baar Virus (EBV) causes sub-clinical infection in infants and if the infection is delayed until adulthood, infectious mononucleosis or glandular fever results. It lasts for 2 to 3 weeks.
4. The primary acute infection caused by HSV-1 is _____________
a) chicken-pox
b) genital lesions
c) stomatitis
d) glandular fever
Explanation: The primary acute infection caused by HSV-1 is stomatitis. It also causes infection of the mouth and tongue. Upon reactivation, it causes a cold sore. The site of latency for HSV-1 is the dorsal root ganglion of the trigeminal (cranial) nerve.
5. Which of the following virus is transmitted through the respiratory route?
a) HIV
b) HBV
c) HPV
d) Rhinovirus
Explanation: Rhinovirus is the virus that is transmitted through the respiratory route. Whereas Human Immunodeficiency Virus (HIV), Hepatitis B Virus (HBV), and Papillomavirus (HPV) are transmitted through sexual routes.
6. Which of the following phylum acts as a vector for virus transmission?
a) Arthropods
b) Mollusca
c) Porifera
d) Cnidaria
Explanation: Arthropods found in tropical parts, act as a vector for virus transmission. The arthropod feeds on the human body by piercing the skin with their mouthparts. During their next meal, they inject saliva as an anticoagulant, and in doing so introduces the virus that was picked up from the previous meal.
7. The viruses spread by arthropods are known as ____________
a) Rhinovirus
b) Arbovirus
c) Influenza virus
d) HIV
Explanation: The viruses spread by arthropods (arthropod-borne virus) are known as arbovirus and the disease spread by arbovirus is known as arboviral disease. The infection usually occurs during warm weather months when mosquitoes and ticks are active.
8. Which of the following is an example of a vertically transmitted virus?
a) Arbovirus
b) Rhinovirus
c) Poliovirus
d) Rubella virus
Explanation: The rubella virus is a classic example of a vertically transmitted virus. It spreads by the respiratory route. The risks of malformations arising from rubella virus infection are high in the early stages of pregnancy and it becomes almost no risk by the fifth month or later stages.
9. Which of the following virus undergoes zoonotic transmission?
a) Rhinovirus
b) HIV
c) HBV
d) Rhabdovirus
Explanation: Rhabdovirus transmits through the zoonotic transmission. It causes rabies which is a well-known zoonosis. It is transmitted directly by the bite of an infected vertebra and it infects many different species.
10. Which of the following virus belongs to the poxvirus family?
a) HIV
b) Myxoma
c) Measles
d) Influenza
Explanation: Myxoma virus belongs to the poxvirus family. The natural host of myxoma virus is the South American rabbit in which it causes minor skin outgrowths. It also infects the European rabbit causing myxomatis and is spread by arthropod vectors.