SOKOINE UNIVERSITY OF AGRICULTURE
VM 132: Animal Microbiology CAT 2 Total Marks: 58 Date: 16th January 2023 Time: 30 minutes
General instructions: Answer all questions in both sections (A and B). Any cancelled and or rubbed answer will be given a zero mark.
SECTION A: VIROLOGY
1. Select the best answer among the alternative statements given for each question and circle it (12 marks)
i. A chemical component that is found in all viruses is:
A) Protein B) Lipid C) DNA D) RNA E) Glycoproteins
ii. Which of the following internalization method is mostly used by enveloped viruses to enter a cell:
A) plasma membrane fusion B) endocytosis
C) integration D) pore formation
iii. 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) Provirus D) DNA
E) RNA F) Both RNA and DNA
iv. Which of the following is the correct set of acellular microorganisms?
A) viruses, protists, viroids and archea
B) virusoids, prions, viruses and protists
C) viruses, prions, viroids and virusoids
D) prions, bacteria, viruses and archea
v. Viruses are referred to as obligate intracellular parasites because
A) viral DNA inserts itself into host DNA
B) they use host energy to live
C) they replicate only in living cells
D) they are non-living
vi. Viruses are made of
A) Protein coat, DNA
B) Protein coat, RNA
C) Protein coat, DNA or RNA
D) Protein coat, DNA and RNA
2. Write a word or phrase that best fits in the blank spaces below (12 marks)
i. The outer shell of the virus which encloses the genetic material (composed of capsomers) is called_____________________________________________________________________________
ii. The internal part of a virus particle, which consists of the nucleic acid (either DNA or RNA never both) and closely associated proteins ______________________________________
iii. The virus always will attach to the ____________________________ present on the surface of cell using __________________________________ present on the surface of the virus.
iv. The process of bringing two separate membrane bilayers (viral envelope and plasma membrane) into intimate contact and then merging them into one ______________________
v. The process whereby a virus capsid is completely or partially removed and the virus genome exposed __________________________________________________________________
vi. The enzyme that MUST be packaged by -ssRNA viruses within their virion for replication and transcription ________________________________________________________________
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 (14 marks).
| LIST A | LIST B |
| i. Tobacco mosaic virus, Ebola virus, influenza, measles and rabies virus are examples of viruses with ____________________ capsid symmetry
ii. Baltimore classified viruses into_______________ groups based on their genomes iii. Replication of RNA viruses typically occurs in the____________ iv. Replication of DNA viruses typically occurs in the____________ v. The mechanism used by most of the non-enveloped viruses to leave the cell after replication_____________________________ vi. Named based on how they were originally thought to be contracted_____________________________________________ vii. Viruses originated from cellular (RNA and DNA) genetic material that has acquired the capacity to exist and function independently__________________________________________ |
A. Bunyaviruses
B. Dengue virus C. Reduction hypothesis D. Escape hypothesis E. Nucleus F. Cytoplasm G. Budding H. Lysis I. Icosahedral J. Helical K. Seven L. Two |
SECTION B: MYCOLOGY
a) Fill in the correct word/phrase in each of the following sentence (10 Marks).
1. ____________________ grow as a single-celled organism and reproduce by budding.
2. ____________ require organic nutrients and grow as parasite, symbiont or saprotroph.
3. ____________ is sexual stage of fungi characterized by production of sexual spores.
4. _____________ are designated as reproductive structures in fungi.
5. Three morphological structures of fungi are _____________, ______________, ________________.
6. List any two economic significances of fungus ________________________________ and _________________________________.
7. Rumen fungi breaks down __________________ by a process called anaerobic fermentation.
b) Provide three (3) reasons to support the statement that, “Fungi are more closely related to animals than plants” (10 Marks).
1. ___________________________________________________________________
2. ___________________________________________________________________
3. ___________________________________________________________________
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