Uncategorized By Vijay Wardhan • November 30, 2024 1. Certain enzymes like reverse transcriptase, integrase and protease are found in: TMV HIV T2-phage poxvirus Explanation:HIV contains enzymes such as reverse transcriptase, integrase, and protease. These enzymes are essential for the virus’s replication and integration into the host genome. 2. Bacteriophages have been used as: best material for constructing cosmids vector for gene cloning all of the above isolating DNA ligase enzyme Explanation:Bacteriophages have multiple applications in molecular biology, including serving as vectors for gene cloning, constructing cosmids, and isolating enzymes like DNA ligase. 3. The site where the protein coat of virus is synthesized is: mitochondria of the host plasma membrane of the host ribosome of the host RNA of the virus Explanation:The protein coat (capsid) of a virus is synthesized by the host cell’s ribosomes. The viral RNA or DNA directs the host’s ribosomes to produce viral proteins, which then assemble into the capsid. 4. Who among the following discovered virus? A.P. de Candolle Leeuwenhoek Beijerinck Dimitri Ivanowski Explanation:Dimitri Ivanowski is credited with the discovery of viruses. He identified the Tobacco Mosaic Virus (TMV) as a new type of infectious agent that could pass through filters that trapped bacteria. 5. Which of the following is correct regarding AIDS causative agent HIV? (NEET 2016) HIV does not escape but attacks the acquired immune response HIV is unenveloped retrovirus HIV is enveloped virus that contains two identical molecules of single-stranded RNA and two molecules of reverse transcriptase HIV is enveloped virus containing one molecule of single-stranded RNA and one molecule of reverse transcriptase Explanation:HIV is an enveloped virus that contains two identical molecules of single-stranded RNA and two molecules of reverse transcriptase. This allows it to convert its RNA into DNA and integrate into the host’s genome. 6. Chrysanthemum stunt disease and potato spindle tuber disease are caused by: virion prions none of these viroids Explanation:Chrysanthemum stunt disease and potato spindle tuber disease are caused by viroids, which are small, circular RNA molecules that can infect plants and cause disease. Unlike viruses, viroids do not have a protein coat. 7. Who named prion? Gajdusek Prusiner Temin Stanley Explanation:Stanley B. Prusiner coined the term “prion” to describe the proteinaceous infectious particles responsible for neurodegenerative diseases. His work on prions earned him the Nobel Prize in Physiology or Medicine in 1997. 8. Infective nature of Tobacco mosaic disease was discovered by: Ivanowski Mayer Green Bawden Explanation:Adolf Mayer discovered the infectious nature of Tobacco Mosaic Disease. He demonstrated that the disease could be transmitted from plant to plant, laying the groundwork for the study of plant viruses. 9. Which of the following protein is associated with prion disease? PrP PrPc Interferon PrPsc Explanation:PrPsc is the abnormal, disease-causing form of the prion protein. It induces the misfolding of the normal cellular prion protein (PrPc), leading to the development of prion diseases. 10. Genetic material of TMV is: DNA RNA none of these both Explanation:The Tobacco Mosaic Virus (TMV) has RNA as its genetic material. This was one of the first viruses to be discovered and studied, providing significant insights into the nature of viral genetic material. 11. Infective portion of a virus is nucleic acid, this was discovered by: Hershey and Chase d’Herelle Ivanowski Stanley Explanation:Hershey and Chase’s experiments with bacteriophages demonstrated that the nucleic acid (DNA) is the infective part of the virus. Their work confirmed that DNA carries genetic information. 12. A substance (a low molecular weight protein) produced by host cells in response to viral infection, that protects other cells against further viral infection is: antibody phytotoxin hormone interferon Explanation:Interferons are proteins produced by host cells in response to viral infections. They help protect other cells from infection by interfering with viral replication and activating immune responses. 13. Which of the following is true for viruses? Behave as if they are plants Multiply only in host cells Occur only inside bacteria Are made-up of proteins only Explanation:Viruses can only multiply within the living cells of a host organism. They lack the cellular machinery necessary for independent replication and rely on the host’s cellular processes to reproduce. 14. In Herpes virus DNA is: single stranded double stranded none of the above is correct may be single or double stranded Explanation:Herpes viruses contain double-stranded DNA as their genetic material. This allows them to integrate into the host’s genome and establish latent infections. 15. In which of the following, RNA is double stranded: wound tumour virus reovirus none of the above both (a) and (b) Explanation:Both reovirus and wound tumour virus have double-stranded RNA as their genetic material. This is a unique characteristic among viruses, as most RNA viruses have single-stranded RNA. 16. Viruses have: only DNA only RNA either RNA or DNA both RNA and DNA Explanation:Viruses can have either RNA or DNA as their genetic material, but not both. This genetic material is enclosed within a protein coat and is essential for the virus’s ability to infect host cells and replicate. 17. What is a vector? Natural reservoir of disease An organism which carries and transmits disease causing microorganism Pathogenic protozoa Human parasite Explanation:A vector is an organism that carries and transmits pathogens to other living organisms. Examples include mosquitoes transmitting malaria and ticks transmitting Lyme disease. 18. Group of viruses, which attack members of Myxophyceae are termed as: cyanophages bacteriophages phages only mosaic virus Explanation:Cyanophages are viruses that specifically infect cyanobacteria (Myxophyceae). These viruses play a role in regulating cyanobacterial populations in aquatic ecosystems. 19. Bacteria differ from viruses in being sensitive to: tetracycline sugars fats and oils proteins Explanation:Tetracycline is an antibiotic that targets bacterial cells, inhibiting protein synthesis. Viruses, which lack cellular machinery, are not affected by antibiotics like tetracycline. 20. Viruses are considered to be: non-living objects living organisms living organisms which have lost power of multiplication a transitional group between living and non-living Explanation:Viruses exhibit characteristics of both living and non-living entities. They can replicate and evolve but only within a host cell, making them a transitional group between living and non-living. 21. In order to label the coat alone but not the nucleic acid the bacteriophage should be grown on E. coli cells previously cultured on a medium containing: 35S 32P 3 H 14C Explanation:Sulfur-35 (35S) is used to label proteins because sulfur is found in the amino acids methionine and cysteine, which are components of proteins. Phosphorus-32 (32P) would label nucleic acids, not the protein coat. 22. Prions are pathogens that are thought to consist solely of: DNA RNA _ _ 174 proteins Explanation:Prions are infectious agents composed solely of proteins. They cause neurodegenerative diseases by inducing abnormal folding of normal cellular proteins, particularly in the brain. 23. In which of the following, RNA is the genetic material? Influenza virus TMV All of the above Poliomyelitis virus Explanation:TMV, Influenza virus, and Poliomyelitis virus all have RNA as their genetic material. These RNA viruses rely on RNA-dependent mechanisms for replication within host cells. 24. The truncated cone of HIV consists of: lipids and carbohydrates protein 41 and protein 29 none of the above protein 24 capsid subunit and protein 17 matrix Explanation:The truncated cone-shaped core of HIV consists of the protein 24 capsid subunit and protein 17 matrix. These proteins form the structural framework of the virus. 25. The smallest known agent of a plant disease is: viroid virus mycoplasma bacteria Explanation:Viroids are the smallest known agents of plant disease. They are composed of a short strand of circular RNA and lack a protein coat, making them unique among pathogens. 26. Which is an exception to cell theory? Fungi Bacteria Lichens Viruses Explanation:Viruses are considered an exception to cell theory because they are not made up of cells. They are acellular entities that require a host cell to replicate and do not exhibit characteristics of living cells outside a host. 27. Kuru, a human disease is caused by: viroid virus prion PPLO Explanation:Kuru is a human disease caused by prions. It was transmitted through ritualistic cannibalism practiced by the Fore people of Papua New Guinea, leading to neurodegenerative symptoms. 28. The virus responsible for AIDS is an example of a (an): mosaic virus adenovirus retrovirus T-even virus Explanation:The virus responsible for AIDS is the Human Immunodeficiency Virus (HIV), which is a retrovirus. Retroviruses use reverse transcriptase to convert their RNA into DNA, which integrates into the host’s genome. 29. Who discovered cyanophages? Wollman Hershey and Chase Lindeman Shafferman and Moris Explanation:Shafferman and Moris are credited with discovering cyanophages, viruses that infect cyanobacteria. Their work helped to understand the interactions between viruses and cyanobacteria in aquatic environments. 30. An infectious agent associated with certain mammalian degenerative disease that is composed solely of protein, is known as: virus prion virion mycoplasma Explanation:Prions are infectious agents composed solely of proteins. They are responsible for several neurodegenerative diseases in mammals, including Creutzfeldt-Jakob disease and mad cow disease. 31. Infective part of virus was discovered by: d’Herelle Hershey and Chase Ivanowski Stanley Explanation:Hershey and Chase conducted experiments using bacteriophages to demonstrate that DNA is the genetic material responsible for infecting bacteria. Their work provided crucial evidence that DNA carries genetic information. 32. The lambda phase is a: lytic phage lysogenic phage none of these virulent phage Explanation:The lambda phage is a lysogenic bacteriophage. It can integrate its DNA into the host bacterium’s genome and remain dormant until it is induced to enter the lytic cycle. 33. The genetic material of poxvirus is: double stranded RNA single stranded RNA circular DNA single stranded DNA Explanation:Poxviruses have double-stranded DNA as their genetic material. This allows them to replicate within the cytoplasm of the host cell, independent of the host’s nuclear machinery. 34. First animal pathogenic virus was discovered by: Stanley Ivanowski Loeffer and Frosch Adolph Mayer Explanation:Loeffer and Frosch discovered the first animal pathogenic virus, the foot-and-mouth disease virus. This discovery was significant in understanding viral diseases in animals. 35. The capsid of TMV is made-up of nearly: 1,800 capsomeres 2,130 capsomeres 2,00,000 capsomeres 1,200 capsomeres Explanation:The capsid of the Tobacco Mosaic Virus (TMV) is composed of approximately 2,130 capsomeres. These protein subunits form the helical structure that encases the viral RNA. 36. Name the scientist who called viruses as “Contagium vivum fluidum”: Twort Beijerinck Bawden and Pierie d’ Herelle Explanation:Martinus Beijerinck coined the term “Contagium vivum fluidum” to describe viruses, emphasizing their infectious nature and fluid-like properties. His work laid the groundwork for the field of virology. 37. Yellow vein Mosaic of Bhindi Virus (Hibiscus Virus-I) is transmitted through: butterflies white flies fungal mycelium moth Explanation:The Yellow Vein Mosaic Virus of Bhindi (Okra) is transmitted by whiteflies. These insects act as vectors, spreading the virus from infected to healthy plants. 38. RNA particle causing symptoms like that of a virus disease are known as: virion viroids none of these HIV Explanation:Viroids are small, circular RNA molecules that can infect plants and cause disease. Unlike viruses, viroids do not have a protein coat and rely entirely on their RNA for infection. 39. Longest known virus is: TMV _ _ 174 T1 phase Citrus tristeza Explanation:The Tobacco Mosaic Virus (TMV) is one of the longest known viruses. It has a rod-shaped structure and was one of the first viruses to be studied in detail. 40. Cyanophage is a virus that attacks: bacteria blue-green algae all animals all plants Explanation:Cyanophages are viruses that specifically infect cyanobacteria, also known as blue-green algae. These viruses play a role in controlling cyanobacterial populations in aquatic environments. 41. In a bacteriophage, DNA is present in: tail head in tail fibres only head and tail Explanation:In a bacteriophage, the DNA is located in the head of the virus. The head is a protein structure that encases the viral DNA, protecting it until it can be injected into a host bacterium. 42. TMV was isolated in crystalline form by: E.C. Stakmanz W.M. Stanley D. Ivanowski K.M. Smith Explanation:W.M. Stanley was the first to crystallize the Tobacco Mosaic Virus (TMV), demonstrating that viruses could be purified and studied in a crystalline form. His work earned him the Nobel Prize in Chemistry. 43. AIDS (= Acquired Immune Deficiency Syndrome) is caused by: fungal spores bacterium pollen grains virus HLTV III or LAV or ARV Explanation:AIDS is caused by the Human Immunodeficiency Virus (HIV), which was initially referred to as HTLV-III, LAV, or ARV. HIV attacks the immune system, leading to a progressive failure of immune function. 44. Number of capsomeres forming capsid of TMV is: 2100 2000 2130 2105 Explanation:The capsid of the Tobacco Mosaic Virus (TMV) is composed of 2130 capsomeres. These protein subunits form a helical structure that encases the viral RNA. 45. Virus and bacteriophage are made-up of: nucleoprotein protein DNA and RNA lipoprotein Explanation:Both viruses and bacteriophages are composed of nucleoproteins, which include nucleic acids (DNA or RNA) surrounded by a protein coat. This structure is essential for their ability to infect host cells. 46. Which of the following disease is caused by virus? Typhoid T.B. Polio Diphtheria Explanation:Polio is caused by the poliovirus, which infects the nervous system and can lead to paralysis. The disease has been largely eradicated through widespread vaccination efforts. 47. The first to isolate a plant virus was: E.C. Stakmann W.M. Stanley D. Ivanowski R.M. Smith Explanation:W.M. Stanley was the first to crystallize and isolate the Tobacco Mosaic Virus (TMV), proving that viruses could be isolated and studied in a purified form. His work laid the foundation for modern virology. 48. Interferon is a: RNA used for DNA synthesis low molecular weight protein which inhibits viral multiplication (Intracellular viral replication) none of the above proteins used for transportation of oxygen Explanation:Interferons are low molecular weight proteins that inhibit viral replication within host cells. They are part of the body’s innate immune response to viral infections. 49. Smallpox is caused by: bacteria virus mosquito housefly Explanation:Smallpox is caused by the Variola virus. It was a highly contagious and deadly disease before being eradicated by a global vaccination campaign. 50. The fact that best supports the concept that viruses are living is that viruses: duplicate themselves are made-up of common chemicals penetrate cell membrane cause disease Explanation:The ability of viruses to replicate themselves is a key characteristic that supports the notion that they are living entities. They can reproduce, but only within the living cells of a host organism. 51. Detailed study of bacteriophage was made by: Stanley Ivanowski d’Herelle Twort Explanation:Felix d’Herelle conducted detailed studies on bacteriophages, viruses that infect bacteria. His work provided significant insights into the nature and behavior of bacteriophages. 52. D.C. Gajdusek was awarded the Nobel Prize for discovery of prion based diseases in: 1979 1976 1995 1980 Explanation:D.C. Gajdusek was awarded the Nobel Prize in 1976 for his work on prion diseases, particularly for his discovery of the infectious nature of kuru, a neurodegenerative disease found in Papua New Guinea. 53. Enzymes are absent in: bacteria algae viruses fungi Explanation:Viruses lack the cellular machinery, including enzymes, required for metabolic processes. They rely entirely on the host cell’s enzymes to carry out replication and other functions. 54. Virion refers to: dead virus capsid of virus complete form of virus nucleic acid of virus Explanation:A virion is the complete, infectious form of a virus outside a host cell. It includes the viral genome (nucleic acid) and the protein coat (capsid) that encases it. 55. Viroids have: single stranded DNA not enclosed by protein coat single stranded RNA not enclosed by protein coat (naked RNA) double stranded RNA enclosed by protein coat double stranded DNA enclosed by protein coat Explanation:Viroids are composed of single-stranded RNA that is not enclosed by a protein coat. This naked RNA is capable of infecting plants and causing disease. 56. Bacteriophage consists of: DNA only fats proteins only nucleoproteins Explanation:Bacteriophages are composed of nucleic acids (DNA or RNA) surrounded by a protein coat. This combination of nucleic acids and proteins is referred to as nucleoproteins. 57. Viruses are commonly transmitted in plants through: water wind animals sucking insects (Insect vectors) Explanation:Viruses are commonly transmitted in plants through sucking insects such as aphids and whiteflies. These insects act as vectors, transferring the virus from infected to healthy plants. 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