SOKOINE UNIVERSITY OF AGRICULTURE
College of Veterinary Medicine and Biomedical Sciences
VM 232: Virology Part Total Marks: 100 Date: 29th June 2022 Time: 1 hour
1. Select the best answer among the alternative statements given for each question and circle it (50 marks)
i. Creutzfeldt-Jakob disease (CJD), kuru, scrapie, and Mad Cow disease are caused by:
A) Viroids B) Retroviruses
C) DNA viruses D) Prions E) RNA viruses
ii. Which of the following has the largest genome of all human viruses?
A) Poxvirus B) Herpesvirus
C) Hepadnavirus D) Adenovirus
iii. A chemical component that is found in all viruses is:
A) Protein B) Lipid C) DNA
D) RNA E) Carbohydrate
iv. A structural component that is found in all viruses is:
A) The envelope B) DNA C) Capsid
D) Tail fibers E) Matrix core
v. Which of the following is not true of virions?
A) Reproduce independently B) Contain DNA
C) Contain RNA D) Are extracellular
vi. A common polyhedral capsid shape of viruses is a:
A) Pentagon B) Cube C) Icosahedron D) Pyramid E) Sphere
vii. The viral nucleocapsid is the combination of
A) genome and capsid B) capsid and spikes
C) envelope and capsid D) capsomere and capsid
viii. In the simplest capsid, there is a capsomere at each of the 12 vertices; this capsomere, which is surrounded by five other capsomeres, is termed a
A) penton B) polyhedral
C) icosahedral D) helical
ix. Which of the following is not an RNA virus?
A) Retrovirus B) Enterovirus
C) Rhabadovirus D) Adenovirus E) Rubellavirus
x. Viruses that contain two complete copies of positive strand RNA and the enzyme reverse transcriptase are:
A) Toga viruses B) Rhabdoviruses
C) Retroviruses D) Reoviruses
E) Enteroviruses
xi. The process whereby progeny viruses acquire their envelope:
A) Fusion B) Viropexis C) Budding
D) Engulfment
xii. Poxviruses replicate:
A) On a plasmid B) In the cytoplasm
C) Nucleus D) Within the nucleus
xiii. Replication of RNA viruses typically occurs in the:
A) Nucleus B) Golgi
C) Endoplasmic reticulum D) Cytoplasm
xiv. Replication of DNA viruses typically occurs in the:
A) Golgi B) Cytoplasm
C) Nucleus D) Endoplasmic reticulum
xv. Which of the following internalization method is mostly used by enveloped viruses to enter a cell:
A) fusion B) endocytosis
C) integration D) pore formation
xvi. In order for a virus to replicate inside a cell, what component of the virus must enter the cell?
A) the genome B) the capsid
C) capsid D) envelope
xvii. Which viruses always have an RNA genome that acts as a template for DNA synthesis?
A) reoviruses B) retroviruses
C) hepadnaviruses D) influenza A virus
xviii. Which viruses appear to be hypermutable?
A) DNA viruses B) ‘Emerging’ viruses C) Influenza and HIV D) RNA viruses
xix. Viruses largely lack metabolic machinery of their own to generate energy or to synthesize….
A) protein B) carbohydrate
C) capsid D) nucleic acids
xx. Reverse transcriptase is a useful enzyme to have when
A) an RNA virus converts its RNA to DNA
B) a DNA virus converts its DNA to RNA
C) an RNA virus converts its DNA to RNA
D) a virus lacks metabolic machinery
xxi. When a virus enters a cell but does not replicate immediately, the situation is called
A) lysogeny B) latent C) symbiosis
D) synergism E) incubation F) lytic
xxii. The first step in infection of a host cells by a virus is called
A) adsorption B) absorption C) abruption D) penetration E) replication F) fusion
xxiii. In the one-step growth curve, the time from infection until lysis is known as
A) eclipse period B) rise period
C) latent period D) burst size
xxiv. Inclusion bodies of rabies virus are called:
A) intracytoplasmic B) intranuclear
C) Negri bodies C) both (a) and (b)
D) none of the above
xxv. All negative sense RNA viruses have:
A) no envelope
B) envelope
C) segmented genomes only
D) non-segmented genomes only
E) no RNA-dependent RNA polymerase
2. Indicate whether the following statements are true or false by writing TRUE for correct statement and FALSE for incorrect statement in the space provided (20 marks)
i. Most viruses replicate by means of binary fission except HIV……………………………………………
ii. Viruses are found everywhere in the universe affecting all cellular organisms except bacteria…………..
iii. The host range of viruses is determined by specific host attachment sites and cellular factors……………
iv. As opposed to bacteria, viruses contain protein synthesis machinery necessary for their survival from one organism to another……………………………………………………………………………………
v. The main living characteristic of a virus is the ability of a virus to reproduce and carry out next generation at a fantastic rate, but only in living host cells………………………………………………..
vi. Viruses can be used by scientist to transfer genes between organisms…………………….
vii. The synthesis of viral proteins for all viruses is carried out in the cytoplasm using the virus machinery…………………………………………………………………………………………………..
viii. Enveloped viruses acquire envelopes by generating it themselves during replication in the cell………..
ix. In the (-) sense RNA genomes, the (+) strands and mRNA are the same…………………………….
x. All DNA viruses replicate in the nucleus except retrovirus replicate in the cytoplasm……………….
3. Select the answer among the alternatives given in list B that best matches with the statement in list A, then write the letter of the correct response in spaces provided in list A (30 marks)
| LIST A | LIST B |
| i. Baltimore classification of viruses……………………………………………
ii. Named based on how they were originally thought to be contracted………… iii. Papova-, hepadna-, circo-, herpes-, pox-, and adeno- viruses………………. iv. Tobacco mosaic virus, Ebora virus, influenza, measles and rabies virus are examples of viruses with ……………….. capsid symmetry v. Viruses originated from cellular (RNA and DNA) genetic material that has acquired the capacity to exist and function independently………………………. vi. Reo-, orthomyxo-, rhabdo-, retro-, bunya-, filo-, corona- viruses………….. vii. Example of a virus with the nature of the symmetry not fully understood giving an appearance of untidy ball of wool………………………………………. viii. Internalization mechanism used by most enveloped viruses……………… ix. A form of a virus when outside the cell…………………………………….. x. The mechanism used by most of the non-enveloped viruses to leave the cell after replication……………………………………………………………… xi. The process of bringing viral envelope and cellular plasma membrane into intimate contact and then merging them into one…………………………… xii. The enzyme that MUST be packaged by -ssRNA viruses within their virion for replication and transcription…………………………………………….. xiii. Viral proteins such as enzymes or transcription factors for virus replication which are not incorporated in the virus are called…………………………………… xiv. A cell with the capacity to replicate the virus is called……………………… xv. The integrated retroviral DNA genome is called………………………… |
A. Seven groups
B. Dengue virus C. Regressive theory D. RNA viruses E. Icosahedral F. Six groups G. DNA viruses H. Poxvirus I. Progressive theory J. Helical K. Fusion L. Permissive M. Penetration N. RdDp O. Budding P. Provirus Q. Non-structural proteins R. Lysis S. Susceptible T. Core U. Prion V. RdRp W. Virion X. Endocytosis |
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