Final 2012 PDF

Preview

Summary

DOH 133 past exam...

Description

Faculty of Science School of Biomedical Sciences Session Two Examination 2012

DOH133 Oral Microbiology Question Paper MAY NOT be retained by the Candidate WRITING DURING READING TIME IS PERMITTED ON ALL EXAMINATION MATERIALS

SUBJECT COORDINATOR: Dr Peter Anderson LECTURERS: Dr Peter Anderson, Associate Professor Chapple and Dr Manickam WRITING TIME: 2 hours and 10 mins MATERIALS SUPPLIED BY UNIVERSITY: General Purpose Answer Sheet MATERIALS PERMITTED IN EXAMINATION:

Battery/solar operated calculator (no printer, non-programmable), 2BPencil/Eraser, pens, sharpener

NUMBER OF QUESTIONS: Section A (44 Marks): Multiple Choice 44 questions Section B (20 marks): General Microbiology- three short answer questions Section C (36 Marks): Oral Microbiology- seven short answer questions Total: 100 Marks VALUE: 45% INSTRUCTIONS TO CANDIDATES: Section one (multiple choice questions) should be answered, on the multiple choice sheet provided, in pencil. You may answer Section two (short answer) in the spaces provided in the exam paper (additional paper is available if required). All questions are compulsory. Marks in this paper add up to 100 marks. STUDENT NAME: …………………………………… .STUDENT NUMBER: ……………………. STUDENT SIGNATURE :……………………………………………………………………………

Calculator model (if used) :……………………………………………………………………………….

DOH133 ESE 2012

Page 1 of 13

SECTION A: MULTIPLE CHOICE QUESTIONS Choose the one alternative that best completes the statement or answers the question. Each multiple choice question is worth one (1) mark.

THE MULTIPLE CHOICE ANSWER SHEETS PROVIDED MUST BE COMPLETED IN PENCIL. 1. Bacteriophages derive all of the following from the host cell EXCEPT A. tRNA. B. amino acids. C. nucleotides. D. lysozyme. E. ATP. 2. Lysogeny would be best described as A. lysis of the host cell due to phage infection. B. phage DNA is incorporated into host-cell DNA. C. a period during replication when virions are not present. D. an unusually long burst time. E. the process of phage attaching to the cell. 3. Which of the following matches the name given to an infectious protein with an abberant form of the protein that will cause disease: A. retrovirus--PrPSc B. prion--retrozyme C. retrovirus--retrozyme D. prion--PrPSc E. scrapie--RNAse 4. Some virus infections, such as infection with Human Herpes Virus 1, infect a cell without causing initial symptoms. These are called A. latent viruses. B. lytic viruses. C. enveloped viruses. D. slow viruses. E. unconventional viruses. 5. Oncogenic viruses: A. cause acute infections. B. are genetically unstable. C. cause tumors to develop. D. are lytic viruses that kill the host cell. E. have no effect on the host cell. 6. In specialized transduction, when the defective phage enters a new bacterial cell A. only phage DNA integrates into the chromosome of the new host cell B. only bacterial DNA from the previous bacterial host integrates into the chromosome of the new host cell C. both phage DNA and bacterial DNA integrate into the chromosome of the new cell host D. the DNA is destroyed E. Neither phage or bacterial DNA become integrated into the chromosome of the new host, but rather remain in the cytoplasm on a plasmid.

DOH133 ESE 2012

Page 2 of 13

7. A viroid is a(n) A. complete, infectious virus particle. B. infectious piece of RNA without a capsid. C. capsid without nucleic acid. D. provirus. E. infectious protein. 8. Most RNA viruses code for which of the following enzymes A. DNA-dependent DNA polymerase B. lysozyme C. RNA-dependent RNA polymerase D. reverse transcriptase E. ATP synthase 9. An example of a latent viral infection is A. subacute sclerosing panencephalitis. B. cold sores. C. influenza. D. smallpox. E. mumps. 10. Which of the following statements about viral spikes is FALSE? A. They are composed of carbohydrate-protein complexes. B. They are used for attachment. C. They may cause hemagglutination. D. They bind to receptors on the host cell surface. E. They are found only on nonenveloped viruses. 11. Bacteriophage replication differs from animal virus replication because only bacteriophage replication involves A. adsorption to specific receptors. B. assembly of viral components. C. replication of viral nucleic acid. D. injection of naked nucleic acid into the host cell. E. lysis of the host cell. 12. When a recipient bacterial cell receives bacterial DNA via transduction A. the new DNA must enter a new bacteriophage or it is lost B. the DNA is destroyed C. the DNA is changed to match that of the recipient D. the new DNA is replicated every time the recipient multiplies E. the recipient is usually killed 13. A virus’s ability to infect an animal cell depends primarily upon the A. host cell’s ability to phagocytize viral particles. B. presence of receptor sites on the cell membrane. C. type of viral nucleic acid. D. enzymatic activity of a host cell. E. presence of pili on the host cell wall.

DOH133 ESE 2012

Page 3 of 13

14. The most conclusive evidence that viruses cause cancers is provided by A. finding oncogenes in viruses. B. the presence of antibodies against viruses in cancer patients. C. cancer following injection of cell-free filtrates. D. treating cancer with antibodies. E. some liver cancer patients having had hepatitis. 15. The mechanism whereby an enveloped virus leaves a host cell is called A. transduction. B. budding. C. abduction. D. lysogeny. E. penetration. 16. Fungal hyphae that have no cross-walls so have many nuclei in the same cytoplasm are called: A. septate B. coenocytic C. multinucleate D. plasmodia; E. myxotic 17. A fungus that can grow as two forms: yeast or mold is called: A. bisexual B. dimorphic C. pleiomorphic D. teleomorphic E. pathomorphic 18. Fungi are A. autoheterotrophs B. autotrophs C. chemoheterotrophs D. chemoautotrophs E. lithotrophs 19. Lichens A. are a mutualistic relationship between a fungus and a protozoa B. are parasitic relationship between a fungus and an alga. C. are made of two different fungi living in a mutualistic relationship with an alga. D. are mutualistic relationship between a fungus and a photosynthetic partner. E. are made of two different fungi living in a parasitic relationship 20. Which of the following pairs is mismatched? A. Plasmogamy : union of two haploid cells B. Karyogamy : fusion of nucleus C. tRNA : used to identify Deuteromycetes using molecular techniques D. Meiosis : cell division resulting in haploid cells E. Anamorph : produces asexual spores

DOH133 ESE 2012

Page 4 of 13

Table 1 1-Arthroconidium 2-Ascospore 3-Basidiospore 4-Blastoconidium

5-Chlamydoconidium 6-Conidiospore 7-Sporangiospore 8-Zygospore

21. In Table 1 which of the spores are sexual spores? A. 2, 3, 8 B. 1, 2, 3, 8 C. 1, 4, 5, 6, 7 D. 8 only E. 2, 8 22. In Table 12.1 the sexual spores and asexual spores of mushrooms are___ and ___ respectively: A. 2, 7 B. 3, 6 C. 6, 2 D. 6, 3 E. 3, 7 23. Fungi, more often than bacteria, are responsible for spoilage of jams because A. they have a fermentative metabolism. B. they can tolerate low moisture environments. C. they can tolerate high osmotic pressure. D. they can tolerate low-osmotic pressure. E. they prefer a neutral environment (pH 7). 24. Which of the following statements about the Oomycete algae is false A. They form hyphae B. They have motile zoospores C. They are pathogenic D. They have chitin cell walls E. They reproduce sexually 25. A nosocomial infection is A. always present, but is inapparent at the time of hospitalization. B. acquired during the course of hospitalization. C. always caused by medical personnel. D. only a result of surgery. E. always caused by pathogenic bacteria. 26. Which of the following is a fomite? A. Raw chicken infected with Salmonella B. Droplets from a sneeze C. Airborne spores D. A mosquito carrying disease E. A used syringe

DOH133 ESE 2012

Page 5 of 13

27. Assume a patient had chickenpox (Human Herpes Virus 3) as a child. Which line on Figure 1 below shows the number of viruses present in this person as a 60-year-old with shingles?

A. B. C. D. E.

a b c d e

Figure 1: Virion titre 28. The major significance of Robert Koch's work is that A. microorganisms are present in a diseased animal. B. diseases can be transmitted from one animal to another. C. microorganisms can be cultured. D. microorganisms cause disease. E. microorganisms are the result of disease. 29. The following are communicable diseases EXCEPT A. malaria B. AIDS C. tetanus D. tuberculosis E. typhoid fever 30. Which of the following pairs is mismatched? A. salmonellosis - vehicle transmission B. malaria - vector C. None are mismatched D. influenza - droplet transmission E. bacteremia - fomite 31. Transient microbiota differ from normal microbiota in that transient microbiota A. cause diseases. B. are found in a certain location on the host. C. are always acquired by direct contact. D. are present for a relatively short time. E. never cause disease. 32. The rise in herd immunity amongst a population can directly attributed to A. increased use of antibiotics. B. improved handwashing. C. vaccinations. D. antibiotic-resistant microorganisms. E. None of the answers is correct

DOH133 ESE 2012

Page 6 of 13

33. Which of the following is NOT a reservoir of infection? A. a sick person B. a healthy person C. a sick animal D. a hospital E. All can be reservoirs of infection. 34. Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use? A. skin only B. parenteral only C. mucous membranes only D. skin and parenteral E. skin, parenteral, and mucous membranes 35. All of the following are examples of entry via the parenteral route EXCEPT A. injection. B. bite. C. surgery. D. hair follicle. E. skin cut. 36. Gram-negative septic shock results from the following steps. Which is the second step? A. Body temperature is reset in the hypothalamus. B. Fever occurs. C. IL-1 is released. D. LPS is released from gram-negative bacteria. E. Phagocytes ingest gram-negative bacteria. 37. All of the following are used by bacteria to attach to host cells EXCEPT A. M protein. B. ligands. C. fimbriae. D. capsules. E. A-B toxins. 38. All of the following contribute to a pathogen’s invasiveness EXCEPT A. toxins. B. capsules. C. cell wall components. D. hyaluronidase. E. coagulases. 39. An encapsulated bacterium can be virulent because the capsule A. resists phagocytosis B. is an endotoxin C. is an exotoxin D. destroy the host immune cells E. none of the above

DOH133 ESE 2012

Page 7 of 13

40. Which of the following is NOT a predisposing factor of disease? A. lifestyle B. genetic background C. climate D. occupation E. All are predisposing factors of disease. 41. Which organism in Table 2 below most easily causes an infection? A. E. coli O157:H7 B. Legionella pneumophila C. Shigella D. Treponema pallidum E. The answer cannot be determined based on the information provided.

Table 2 Bacterium E. coli O157:H7 Legionella pneumophila Shigella Treponema pallidum

ID50 20 1 10 57

42. A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as A. subacute. B. subclinical. C. latent. D. zoonotic. E. acute. 43. Which of the following definitions is INCORRECT? A. acute: a short-lasting primary infection B. inapparent: infection characteristic of a carrier state C. chronic: a disease that develops slowly and lasts for months D. primary infection: an initial illness E. secondary infection: a long-lasting illness 44. Symptoms of disease differ from signs of disease in that symptoms A. are changes felt by the patient. B. are changes observed by the physician. C. are specific for a particular disease. D. always occur as part of a syndrome. E. None of the answers is correct. F.

END OF SECTION A Please ensure you have put your name and student number on the multiple choice answer GPA sheet provided.

DOH133 ESE 2012

Page 8 of 13

SECTION B: General Microbiology Short Answer Questions ANSWER ALL QUESTIONS Question 1 (8 marks). Define the following terms: (1) Ascospore

(2) Coenocytic

(3) Hyphae

(4) Plasmogamy

(5) Lichen

(6) Oomycete

(7) Zygospore

(8) Mycosis

DOH133 ESE 2012

Page 9 of 13

Question 2(6 marks): Name a common A/B toxin. Is an A/B toxin an endotoxin or an exotoxin? Explain the general function of the A and B domains of these toxins

Question 3 (6 marks). Antibiotics can kill Gram-negative bacteria, but symptoms of fever and low blood pressure can persist. Explain why

DOH133 ESE 2012

Page 10 of 13

SECTION C: Oral Microbiology Short Answer Questions ANSWER ALL QUESTIONS Question 1 (10 Marks): List and describe five (5) ways that saliva modulates bacterial growth: (i)

(ii)

(iii)

(iv)

v)

DOH133 ESE 2012

Page 11 of 13

Question 2 (4 Marks): Explain why some bacteria from the oral cavity are unculturable:

Question 3 (8 Marks): List the eight (8) elements of a comprehensive infection control plan:

Question 4 (4 Marks): define periodontal disease and differentiate it from dental caries:

DOH133 ESE 2012

Page 12 of 13

Question 5 (4 Marks): Streptococcus mutans is a term used to describe a collection of many cariogenic species of bacteria, including S. mutans serotypes c,e,f. Differentiate serotype from species.

Question 6 (4 Marks): Ecological plaque hypothesis postulates four causative processes. List and describe each process.

Question 7 (2 Marks): You treat a patient at your surgery whose records indicate they have Hepatitis C. Your assistant sustains a needlestick injury while resheathing the needle used for local anaesthetic. What would be the first thing you would do in this scenario:

---END OF EXAM---

DOH133 ESE 2012

Page 13 of 13...