Microbiology MCQs PDF

Unit 1 Question 1 **Which of the following is an example of natural active immunity?** a) Vaccination against measles b) Recovery from chickenpox c) Treatment of rabies with immune globulin d) Neonatal antibodies received through breast milk #### Question 2...

Unit 1 Question 1 **Which of the following is an example of natural active immunity?** a) Vaccination against measles b) Recovery from chickenpox c) Treatment of rabies with immune globulin d) Neonatal antibodies received through breast milk #### Question 2 **Which statement best describes artificial passive immunity?** a) It involves antibodies produced by the individual's own immune system. b) It is acquired through natural infection. c) It involves the administration of antibodies from an immune individual. d) It provides long-lasting immunity similar to natural infection. #### Question 3 **Which type of immune response is characterized by specificity and memory?** a) Innate immunity b) Acquired immunity c) Immediate hypersensitivity d) Non-specific immune response #### Question 4 **Which cells are primarily involved in the secondary immune response?** a) Naive B cells and T cells b) Memory B cells and T cells c) Neutrophils and monocytes d) Natural killer cells #### Question 5 **CD8+ T cells recognize peptides presented by which type of MHC molecules?** a) MHC I class molecules b) MHC II class molecules c) Both MHC I and MHC II class molecules d) Non-MHC molecules #### Question 6 **What is the primary function of regulatory T cells (Treg)?** a) Produce antibodies b) Assist B cells in antibody production c) Limit or prevent immune responses d) Kill infected or tumor cells #### Question 7 **Which of the following best describes naive lymphocytes?** a) Functionally able to eliminate antigens upon recognition b) Functionally inactive but able to recognize antigens c) Engaged in phagocytosis of pathogens d) Rapidly respond upon re-encounter with the same antigen #### Question 8 **Which cells are considered professional antigen-presenting cells?** a) Erythrocytes, spermatozoids, trophoblast cells b) Dendritic cells, Mo/Mf cells, B lymphocytes c) Neutrophils and monocytes d) NK cells #### Question 9 **What is the primary function of lymph nodes in the immune system?** a) To produce antibodies b) To remove aging and damaged blood cells c) To concentrate antigens, APCs, and lymphocytes d) To synthesize immunoglobulins #### Question 10 **Which type of immune response is initiated by the innate immune system?** a) Specific and adaptive b) Non-specific and rapid c) Long-lasting with memory d) Mediated by lymphocytes #### Question 11 **Which receptor is important for the recognition of microbial lipopolysaccharides (LPS)?** a) TLR2 b) TLR3 c) TLR4 d) TLR9 #### Question 12 **What is the function of M1 macrophages?** a) Promote tissue repair b) Regulate inflammation c) Initiate pro-inflammatory responses d) Produce antibodies #### Question 13 **Which cytokine is primarily involved in the differentiation of naive T cells into Th1 cells?** a) IL-1 b) IL-6 c) IL-12 d) TNF #### Question 14 **Which molecules facilitate the initial weak binding and rolling of neutrophils on endothelial surfaces?** a) Integrins b) Chemokines c) Selectins d) Toll-like receptors #### Question 15 **What role does nitric oxide (NO) play in the immune response?** a) Engages in the formation of granulomas b) Acts as an antiviral cytokine c) Contributes to microbial destruction within phagosomes d) Enhances integrin affinity on leukocytes ### Answers 1. **b) Recovery from chickenpox** 2. **c) It involves the administration of antibodies from an immune individual.** 3. **b) Acquired immunity** 4. **b) Memory B cells and T cells** 5. **a) MHC I class molecules** 6. **c) Limit or prevent immune responses** 7. **b) Functionally inactive but able to recognize antigens** 8. **b) Dendritic cells, Mo/Mf cells, B lymphocytes** 9. **c) To concentrate antigens, APCs, and lymphocytes** 10. **b) Non-specific and rapid** 11. **c) TLR4** 12. **c) Initiate pro-inflammatory responses** 13. **c) IL-12** 14. **c) Selectins** 15. **c) Contributes to microbial destruction within phagosomes**  Unit 4 1. Which of the following molecules function as opsonins? a. IgA and C3a b. IgG and C3b c. IgG and C3d d. C3a and C5a 2. What are the three pathways of complement activation? a. altenative, classical and mannan b. autocrine, cascade and lectin c. alternative, classical and lectin d. amplification, cascade and leukotriene 3. Newborns receive antibodies from their mothers in two ways a. IgM across the placenta and IgG via breast milk b. IgD across the placenta and IgM via breast milk c. IgA across the placenta and IgM via breast milk d. IgG across the placenta and IgA via breast milk 4. Which of the following play a significant role in the defense against helminths? a. IgE antibodies and macrophages b. IgM antibodies and complement c. IgG antibodies and macrophages d. IgE antibodies and eosinophils 5. Which of the following is the second signal for activation of B cells? a. binding of IgG to FeyRIlB receptor  b. binding of C3d to CR2 receptor c. binding of membrane IgM to a microbial surface antigen d. binding of membrane IgD to a soluble antigen 6. which of these cells play an important role in the selection of B cells with high-affinity receptors? a. plasmacytoid dendritic cells b. commensal microorganisms c. macrophages d. follicular dendritic cells 7. What is the final step of complement activation? a. binding of IgG to the surface of a microbe b. formation of the membrane attack complex (MAC) c. binding of C3b to the surface of a microbe d. formation of C3a 8. What is the shared function of IgM and IgG antibodies? a. opsonization b. antibody-dependent cell-mediated cytotoxicity c. complement activation d. mucosal immunity 9. Antibody feedback is mediated by: a. binding of C3d to CR2 on B cells b. binding of IgG to FeyRi on macrophages c. binding of antigen-IgG complex to FcyRIIB on B cells d. binding of antigen-IgM complex to FeyRIIB on B cells 10. Which interaction is essential for isotype switching? a. ICOSL on B cells and ICOS on helper T cells b. CD40 on B cells and CD40L on helper T cells c. CD28 on helper T cells and B7-1 on B cells d. CTLA-4 on helper T cells and B7-2 on B cells  11. Which receptor is of particular importance in the development of follicular helper T cells? a. CD40 b. CD28 c. ICOS d. CTLA-4 12. T-independent antibody response: a. is long-lasting because long-lived plasma cells are generated b. develops in response to protein antigens c. is triggered by the direct activation of B cells that mainly produce IgM d. involves production of high-affinity IgG Unit 5 1. Peripheral tolerance of T cells includes all of these processes EXCEPT: a. anergy b. apoptosis c. receptor editing d. suppression by regulatory T cells 2. How can infection activate autoreactive clones of lymphocytes? a. through molecular mimicry b. by inducing the expression of PD-L1 in the tissue c. by activating the inhibitory receptors on autoreactive B lymphocytes d. through activation of regulatory T cells 3. The mechanisms of central tolerance of B lymphocytes include:  a. regulation by inhibitory receptors, anergy, and deletion b. receptor editing, anergy, and deletion c. development of regulatory cells and deletion d. receptor editing, deletion, and suppression by regulatory T cells 4. Mutations of the FOXP3 gene induce: a. reduced expression of peripheral tissue antigens in the thymus b. defective clearance of immune complexes c. deficiency of regulatory T cells d. deficiency of IgG antibodies 5. Which of the following immune mechanisms are implicated in th allergic rhinitis? a. IgM antibodies, complement and macrophages b. IgE antibodies, Th2 cells and mast cells c. immune complexes, complement and neutrophils d. cytotoxic T cells, helper T cells and IL-17 6. Which of the following diseases is mediated by antibodies (typ a. polyarteritis nodosa b. hay fever c. Graves disease d. Crohn disease 7. Diseases caused by immune complexes a. are otherwise called allergic diseases b. are specitie for a particular tissue c. respond well to treatment with antihistamines d. usually manifest as vasculitis, arthritis and nephritis 8. Which of these diseases is caused by T lymphocytes? a. multiple sclerosis b. myasthenia gravis c. pernicious anemia d. systemic lupus erythematosus  Unit 6 1. Which of these immune disorders is caused by mutations in CD40 ligand? a. Chediak-Higashi syndrome b. X-linked lymphoproliferative syndrome c. X-linked hyper-IgM syndrome d. DiGeorge syndrome 2. What is the main functional deficiency in Chediak-Higashi syndrome? a. defective lysosomal function in phagocytes, NK cells, cytotoxic T cells b. defective production of reactive oxygen species by phagocytes c. defective leukocyte adhesion to endothelial cells and migration into tissues d. lack of class II MHC expression and impaired CD4+ T cell activation 3. Which of these is a possible complication of ……. a. serum sickness b. graft-versus-host disease c. crythroblastosis fetalis d. anaphylaxis 4. The principal agents used to treat or prevent graft reaction are: a. immunosuppressive drugs that inhibit or Kill B lymphostes b. anti-inflammatory agents that act on innate immune cells c. immunosuppressive drugs that inhibit of kill T lymphocytes d. intravenous immunoglobulins that modulate ….. 5. Which of these immune disanders is caused by mutations in CD40 a. X-linked lymphoproliferative syndrome b. Chediak-Higashi syndrome c. DiGeorge syndrome d. X-Linked hyper-IgM syndrome 6. Circle the correct statement regarding acute graft rejection  a. acute rejection result from the injury to the graft parenchyma and blood vessels mediated by alloreactive T cells and antibodies b. The main immunopathogenic mechanism in acute rejection is killing of graft parenchymal cells and endothelial cells by helper T cells. c. Acute rejection is mediated by preexisting antibodies in the host circulation that bind donor endothelial antigens d. The main pathologic mechanism in acute rejection is graft ischemia due to proliferation of vascular smooth muscle cells. 7. Direct allorecognition occurs when a. T cell recognizes processed peptide of allogeneic MHC molecule bound to self MHC molecule on host APC b. preformed antibodies recognize donor antigons on endothelial cells of the recipient c. processed allogeneic MHC molecules are presented on recipient APCs and recognized by T cells d. T cells recognize unprocessed allogeneic MHC molecules on graft APCs 8. Circle the correct statement regarding acute graft rejection. a. The main immunopathogenic mechanism in acute rejection is killing of graft parenchymal cells and endothelial cells by helper T cells. b. Acute rejection results from the injury to the graft parenchyma and blood vessels mediated by alloreactive T cells and antibodies. c. Acute rejection is mediated by preexisting antibodies in the host circulation that bind to donor endothelial antigens. d. The main pathologic mechanism in acute rejection is graft ischemia due to proliferation of vascular smooth muscle cells. 9. What term describes generalized and often uncontrolled inflammatory response?  a. disseminated intravascular coagulation b. sepsis c. septic shock d. acute respiratory distress syndrome 10. The key molecules in the pathogenesis of sepsis are a. lipopolysaccharide of Gram-positive bacteria and cytokines such as TNF-a. and IL-6 b. mannan of Gram-negative bacteria and cytokines such as TGF-ß and IL-10 c. lipopolysaccharide of Gram-negative bacteria and cytokines such as TNF-a. and IL-6 d. lipopolysaccharide of Gram-negative bacteria and cytokines such as TGF -B and IL-1 11. Indirect allorecognition occurs when a. preformed antibodies recognize donor antigens on endothelial cells of the recipient b. T cell recognizes processed peptide of allogeneic MHC molecule bound to self MHC molecule on host APC c. unprocessed allogeneic MHC molecules are presented on recipient APCs and recognized by I cells d. T cells recognize unprocessed allogeneic MHC molecules on graft APCs 12. Circle the correct statement regarding hyperacute graft rejection. a. The main immunopathogenic mechanism in hyperacute rejection is killing of graft parenchymal cells and endothelial cells by helper T cells. b. Hyperacute rejection results from the injury to the graft parenchyma and blood vessels mediated by alloreactive T cells and antibodies. c. The main pathologic mechanism in hyperacute rejection is graft ischemia due to proliferation of vascular smooth muscle cells. d. Hyperacute rejection is mediated by preexisting antibodies in the host circulation that bind to donor endothelial antigens. 13. The principal agents used to treat or prevent graft rejection are: a. immunosuppressive drugs that inhibit or kill T lymphocytes b. anti-inflammatory agents that act on innate immune cells  c. immunosuppressive drugs that inhibit or kill B lymphocytes d. intravenous immunoglobulins that modulate the immune response Unit 7 1. Bacteria that exclusively use the process of fermentation to obtain energy are called: a) Anaerobic bacteria b) Aerobic bacteria c) Psychrophilic bacteria d) Gram-negative bacteria Answer : a. Anaerobic bacteria 2. The reservoir of the infection is: a) A person from whom an infectious agent is transmitted to a susceptible host b) An object from which an infectious agent is transmitted to a susceptible host c) The ability of bacteria to be antibiotic resistant d) The natural environment in which the pathogen normally lives Answer : d. The natural environment in which the pathogen normally lives 3. What is the mechanism of action of penicillin and cephalosporin? a) They affect the protein synthesis of bacteria b) They affect the synthesis of nucleic acids c) They interfere with the synthesis of the bacterial cell wall d) They affect the synthesis of folic acid in bacteria Answer : c. They interfere with the synthesis of the bacterial cell wall  4. Which of these substances can be used as an antiseptic? a) Phenol b) Formaldehyde c) 70% ethanol d) Ethylene oxide Answer : 5. Conjugation requires presence of: a) Bacteriophage genes b) Plasmids c) Insertion sequences d) Resistance genes Answer : b. Plasmids 6. Which of the following is NOT a unique characteristic of Gram-negative bacteria? a) Periplasm b) Outer membrane c) Peptidoglycan d) Lipopolysaccharide Answer : Peptidoglycan 7. Lipopolysaccharide (LPS) is a characteristic of: a) Gram positive bacteria b) Gram negative bacteria c) Spore forming bacteria d) Anaerobic bacteria Answer : b. Gram negative bacteria  8. The role of flagella in bacteria is: a) Bacterial motion b) Conjugation c) Adhesion d) Protective role Answer : a. Bacterial motion Unit 8 1. What is the main function of streptokinase secreted by S. pyogenes? a) Inhibition of fibrin degradation b) Promotion of bacterial growth c) Conversion of plasminogen to plasmin d) Lysis of host cell membranes 2. What is the role of the mucoid or smooth capsule in pneumococcus? a) Promotion of bacterial colonization b) Inhibition of complement activation c) Destruction of host tissue d) Stimulation of inflammatory response 3. What distinguishes S. aureus from other staphylococci? a) Presence of bound coagulase b) Formation of hydrogen peroxide c) Synthesis of streptolysin-S d) Production of free coagulase 4. Which bacterial species inhibits Streptococcus mutans in the oral cavity? a) Enterococcus faecium b) Candida albicans c) Clostridium perfringens d) Enterococcus faecalis 5. How does E.faecalis affect pseudomonas aeruginosa in wounds a) Decreases biofilm secretion b) inhibits bacterial growth  c) Enhances biofilm matrix components d) increases vancomycin resistance 6. What is the role of pili and surface proteins in Neisseria gonorrhoeae? a) Decreasing bacterial shedding b) Enhancing phagocytosis by neutrophils c) Facilitating attachment to host cells d) Preventing genital secretions 7. How is meningococcal infection treated? a) Oral antibiotics b) Vaccination c) Topical antiseptics d) Intravenous administration of ceftriaxone or penicillin 8. Which bacteria cause Bordetella infection exclusively in humans? a) B. pertussis and B. bronchiseptica b) B. pertussis and B. parapertussis c) B. bronchiseptica and B. parapertussis d) B. pertussis and B. avium 9. Which bacterial species is characterized by the production of B-lactamases and PBP2A? a) Streptococcus pyogenes b) Enterococcus faecalis c) Staphylococcus aureus d) Neisseria meningitidis 10. Which factor contributes to the pathogenicity of scarlet fever caused by S. pyogenes? a) Streptokinase b) Streptococcal pyrogenic exotoxins c) Pneumolysin d) B-lactamases 11. What distinguishes S. aureus from other staphylococci? a) Production of free coagulase b) Presence of bound coagulase c) Synthesis of streptolysin-S  d) Formation of hydrogen peroxide 12. Which bacterial species causes urinary tract infections, wound infections, and endocarditis, and has developed vancomycin resistance? a) Streptococcus pneumoniae b) Staphylococcus aureus c) Enterococcus faecalis d) Streptococcus pyogenes 13. Which bacterial species inhibits Streptococcus mutans in the oral cavity? a) Clostridium perfringens b) Enterococcus faecalis c) Enterococcus faecium d) Candida albicans 14. What is the primary mode of transmission for Legionella spp. infections? a) Fecal-oral route b) Infectious aerosols c) Vector-borne transmission d) Direct contact with infected person 15. Which antibody does Gonococci specifically degrade to avoid phagocytosis? a) IgG b) gAl c) IgA2 d) IgM 16. How is meningococcal infection treated? a) Oral antibiotics b) Intravenous administration of ceftriaxone or penicillin c) Topical antiseptics d) Vaccination  Unit 9 How do people typically become infected with Vibrio cholerae? a) Inhalation of contaminated air b) Direct contact with infected individuals c) Ingestion of contaminated water or food d) Through mosquito bites 2. What clinical manifestations are typically associated with cholera? a) Constipation and bloating b) Abdominal pain and fever c) Watery stools resembling rice water d) Presence of blood in stool and inflammation in the intestinal wall **3. What is the primary mechanism by which Enteropathogenic E. coli (EPEC) causes diarrhea? a) Production of toxins in the gut b) Induction of vomiting c) **Disruption of interepithelial bonds d) Activation of inflammatory response 4. What structural feature of Uropathogenic E. coli (UPEC) facilitates colonization of the perineum? a) Bundle-forming pili (BfpA) b) Type 1 pili c) Flagella d) Capsule How does Salmonella bacteria cause inflammation in the intestines during infection? a) By inhibiting the production of cytokines b) By inducing apoptosis in intestinal cells c) By activating MAP kinases and producing inflammatory mediators d) By suppressing the immune response 6. Which species of Shigella causes the most severe form of bacillary dysentery? a) S. flexneri b) S. boydii c) S. sonnei  d) S. dysenteriae type 1 7. Which protein of H. pylori is important for adhesion and persistent colonization of the gastric epithelium? a) Urease b) VacA c) BabA d) CagA 8. What is the primary function of type 4 pili in Pseudomonas aeruginosa? a) Swimming b) Adhesion to epithelial cells c) Biofilm formation(cours prof) d) Lysis of host cells 9. Which specific structure of Vibrio cholerae facilitates its adhesion to the mucous membrane of the digestive system? a) Flagellum b) Pili or fimbriae c) Capsule d) Ribosome 10. Which age group is most susceptible to diarrhea caused by Enteropathogenic E. coli (EPEC)? a) Adolescents b) Elderly individuals c) Infants and young children d) Middle-aged adults 11. Which structure of Enteropathogenic E. coli (EPEC) is essential for adherence to the epithelial cells of the small intestine? a) Bundle-forming pili (BfpA) b) Flagella c) Capsule d) Outer membrane proteins 12. Which Salmonella species expresses the Vi antigen, allowing it to avoid the inflammatory the intestines? a) S. enterica b) S. typhi c) S. paratyphi d) S. flexneri 13. How does Shiga toxin contribute to the development of hemorrhagic diarrhea? a) It reduces the absorption of sodium b) it induces apoptosis in intestinal endothelial cells c) It increases fluid loss in the stool d) It promotes inflammation in the colon 14. What effect does H. pylori infection have on gastrin levels and gastric acid secretion? a) Decreased gastrin levels and decreased acid secretion b) Increased gastrin levels and decreased acid secretion c) Decreased gastrin levels and increased acid secretion d) Increased gastrin levels and increased acid secretion 15. Which effector molecule of Pseudomonas aeruginosa often causes lysis of host cells and is associated with severe infections? a) ExoS b) Ехот c) ExoY d) ExoU 16. What is the characteristic color of Pseudomonas colonies on agar? a) Red b) Blue green  c) Yellow d) Purple Unit 10 1. Tuberculoid leprosy is characterized by a. Strong Th1 immune response to M. leprae and benign course b. Dominance of Th2 immune response and few acid-fast bacilli in the lesion c. Dominance of Th2 immune response and better prognosis d. Enormous numbers of M. leprae in the skin and superficial nerves Answer: A) Strong Th1 immune response to M. leprae and benign course 2. What are the three main clinical forms of anthrax? a. cutaneous, gastrointestinal and inhalation anthrax b. nervous, gastrointestinal and inhalation anthrax c. cutaneous, gestational and inhalation anthrax d. cutaneous, gestational and nervous anthrax Answer : cutaneous, gastrointestinal and inhalation anthrax 3. Which of these Clostridia produces a toxin that causes descending spastic paralysis? a. C. difficile b. C. botulinum c. C. perfringens d. C. tetani Answer : C. tetani 4. What are the important factors in pathogenesis of infections caused by C. difficile? a. potent endotoxin (lipopolysaccharide) and spore b. powerful exotoxins including cytotoxin and enterotoxin c. powerful immune response including phagocytosis and formation of granuloma d. powerful exotoxins including lecithinase and enterotoxin Answer : B. powerful exotoxins including cytotoxin and enterotoxin 5. The infectious cycle of B. burgdorferi involves a. small vertebrates, deer and mosquito vectors (Anopheles) b. cows, deer and mosquito vectors (Anopheles) c. small vertebrates, deer and tick vectors (Ixodes species) d. small vertebrates, deer and lice vectors (Pediculus humanus corporis) Answer : c. small vertebrates, deer and tick vectors (Ixodes species) 6. If the immune response to M. tuberculosis is inadequate (Th2 dominance) the bacterium isn't contained resulting in a. miliary tuberculosis b. fibrocaseous tuberculosis c. secondary tuberculosis d. formation of primary complex Answer : a. miliary tuberculosis 7. Diphtheria is prevented using the a. BCG vaccine b. DPT vaccine c. MMR vaccine d. HPV vaccine Answer : b. DPT vaccine 8. Which of these Clostridia is highly tissue invasive? a. C. difficile b. C. botulinum c. C. perfringens d. C. tetani Answer : c. C. perfringens 9. What is the major action of tetanospasmin? a. stimulation of the production of adenosine triphosphate (ATP) b. inhibition of the release of neurotransmitters such as acetylcholine c. inhibition of the release of inhibitory neurotransmitters such as GABA d. stimulation of the release of inhibitory neurotransmitters such as GABA Answer : c. inhibition of the release of inhibitory neurotransmitters such as GABA 10. Treponema pallidum is transmitted a. sexually and through fomites b. via tick bites and by blood c. sexually and transplacentally d. transplacentally and through fomites Answer : c. sexually and transplacentally 11. Late-stage Lyme disease presents as a. aortitis, Lyme enteropathy, acrodermatitis chronica atro b. arthritis, Lyme encephalopathy, erythema migrans c. arthritis, erythema migrans, acrodermatitis chronica atrophican d. arthritis, Lyme encephalopathy, acrodermatitis chronica atrophi Answer: d. arthritis, Lyme encephalopathy, acrodermatitis chronica atrophi 12. Which of these bacteria cause atypical pneumonia? a. S. pneumoniae, M. pneumoniae b. C. pneumoniae, M. pneumoniae c. C. pneumoniae, S. pneumoniae d. S. pneumoniae, K.pneumoniae Answer : b. C. pneumoniae, M. pneumoniae 13. Trachoma is an eye disease caused by a. C. trachomatis, serovariant D-K b. P. aeruginosa c. H. influenzae d. C. trachomatis, serovariant A-C Answer : a. C. trachomatis, serovariant D-K 14. Tertiary syphilis presents as : a. granulomatous lesions (gummas), cardiovascular and respiratory disease b. skin lesions (rash), cardiovascular and neurological disease c. granulomatous lesions (gummas), cardiovascular and neurological disease d. arthritis, Lyme encephalopathy, acrodermatitis chronica atrophicans Answer : c. granulomatous lesions (gummas), cardiovascular and neurological disease 15. Important virulence factors of M. pneumoniae are a. pertactin and adenylate cyclase toxin b. BabA and vacuolating cytotoxin A c. terminal structure and CARDS toxin d. protein A, enterotoxin Answer : c. terminal structure and CARDS toxin 16. Infection by which of these bacteria can lead to severe sequelae such as pregnancy and infertility? a. C. trachomatis, serovariant D-K b. P. aeruginosa c. H. influenzae d. C. trachomatis, serovariant A-C Answer : C. trachomatis, serovariant D-K 18. What are the components of the DPT vaccine? a. diphtheria toxoid, whole killed B. pertussis, tetanus toxoid b. diphtheria toxoid, whole killed B. pertussis, whole killed C. tetani c. whole killed C. diphtheriae, B. pertussis, and C. tetani d. whole killed C. diphtheriae, B, pertussis toxoid, tetanus toxoid Answer : a. diphtheria toxoid, whole killed B. pertussis, tetanus toxoid 19. Which of these Clostridia causes pseudomembranous colitis? a. C. difficile b. C. botulinum c. C. perfringens d. C. tetani Answer : a. C. difficile 20. What is the major action of botulinum toxin? a. stimulation of the production of adenosine triphosphate (ATP) b. prevents the release of the neurotransmitter acetylcholine c. inhibition of the release of inhibitory neurotransmitters such as GABA d. stimulation of the release of inhibitory neurotransmitters such as GABA Answer : b. prevents the release of the neurotransmitter acetylcholine 21. Borrelia burgdorferi is transmitted a. transplacentally and through fomites b. sexually and through fomites c. via tick bites d. sexually and transplacentally Answer : c. via tick bites 22. In which clinical stage of syphilis are patients contagious : a. primary and secondary b. primary and tertiary c. primary d. primary, secondary and tertiary Answer : a. primary and secondary 23. which of these Clostridia produces a toxin that causes descending flaccid paralysis : a. C. difficile b. C. botulinum c. C. perfringens d. C. tetani Answer :b. C. botulinum 24. Tuberculosis is prevented using the ? a. BCG vaccine b. DPT vaccine c. MMR vaccine d. HPV vaccine Answer : a. BCG vaccine  Unit 11 1. Which of these infectious agents is transmitted through the bite of infected reduvid bug (bed bug)? a. Plasmodium ovale b. Trypanosoma cruzi c. Leishmania donovani d. Giardia lamblia Answer : b. Trypanosoma cruzi 2. Which of these parasites causes mononucleosis-like syndrome? a. Leishmania donovani b. Toxoplasma gondii c. Wuchereria bancrofti d. Giardia lamblia Answer : b. Toxoplasma gondii 3. Which of the following is a sexually transmitted disease? a. malaria b. African sleeping sickness c. Chagas disease d. Trichomoniasis Answer : d. Trichomoniasis 4. Which of these diseases are primarily waterborne? a. Giardiasis, Cryptosporidiosis b. Leishmaniasis, Giardiasis  c. Toxoplasmosis, Leishmaniasis d. Trichomoniasis, Amoebic dysentery Answer : a. Giardiasis, Cryptosporidiosis 5. Which of the following parasites is the carrier of Rickettsia prowazekii? a. Wuchereria bancrofti b. Trichinella spiralis c. Diphyllobothrium latum d. Pediculus humanus corporis Answer : d. Pediculus humanus corporis 6. Eggs of which parasite can be found in urine? a. Ascaris lumbricoides b. Schistosoma haematobium c. Strongyloides stercoralis d. Ancylostoma duodenale Answer : b. Schistosoma haematobium 7. Which of these clinical manifestations can be caused by Trichinella spinalis:? a. myocarditis b. blindness c. chronic dermatitis d. elephantiasis Answer : a. myocarditis 8. Which of these infectious agents is transmitted through the bite of infected female anopheline mosquitoes? a. Plasmodium ovale  b. Trypanosoma cruzi c. Leishmania donovani d. Giardia lamblia Answer : a. Plasmodium ovale 9. Which of these parasites causes malabsorption and malnutrition? a. Leishmania donovani b. Toxoplasma gondii c. Wuchereria bancrofti d. Giardia lamblia Answer : d. Giardia lamblia 10.What disease does Trypanosoma cruzi cause? a. malaria b. African sleeping sickness c. Chagas disease d. Trichomoniasis Answer : c. Chagas disease 11.Leishmaniasis typically affects: a. skin, brain b. liver, bone marrow c. spleen, colon d. eyes, brain Answer : b. liver, bone marrow 12.Infection by which of these parasites can be coupled with megaloblastic anemia a. Plasmodium falciparum b. Trichinella spiralis  c. fish tapeworm (Diphyllobothrium latum) d. canine tapeworm (Echinococcus granulosus) Answer : a. Plasmodium falciparum 13.Which of the infectious agents are transmitted by gcfon of ieclous Cast a. Enterobius vermicularis, Ascaris lumbricoides b. Ancylostoma duodenale, Wuchereria bancrofti c. Ancylostoma duodenale, Strongyloides stercoralis d. Wuchereria bancrofti, Onchocerca volvulus 14.Eggs of which parasite can rarely be found in stool? a. Ascaris lumbricoides b. Schistosoma mansoni c. Strongyloides stercoralis d. Ancylostoma duodenale Answer : Strongyloides stercoralis 15.What is the most severe consequence of onchocerciasis? a. myocarditis b. blindness c. chronic dermatitis d. elephantiasis Answer : b. blindness Unit 12 1. Which of the following is a risk factor for developing candidiasis?  A. Use of narrow-spectrum antibiotics B. Intact skin microflora C. Immunosuppression D. Exposure to high temperatures Answer : C. Immunosuppression 2. Which structure is important for Cryptococcus neoformans' evasion of the host immune system? A. Chloroplast B. Polysaccharide capsule C. Peptidoglycan cell wall D. Ribosome answer : B. Polysaccharide capsule 3. What is the primary way Aspergillus fungi reproduce? A. Binary fission B. Budding C. Forming conidia on conidiophores D. Fragmentation Answer : C. Forming conidia on conidiophores 4. Which of the following fungi is known for its angioinvasive properties similar to Aspergillus? A. Candida albicans B. Rhizopus species C. Cryptococcus neoformans D. Histoplasma capsulatum Answer : B. Rhizopus species  5. What is the common manifestation of Pneumocystis jiroveci infection in immunocompromised patients? A. Gastrointestinal bleeding B. Pulmonary pneumonia C. Skin lesions D. Liver failure Answer : B. Pulmonary pneumonia 6. Which group is at higher risk for contracting sporotrichosis? A. Swimmers B. Office workers C. Foresters, farmers, and gardeners D. Athletes Answer : C. Foresters, farmers, and gardeners 7. Which dermatophyte infection affects the scalp? A. Tinea corporis B. Tinea pedis C. Tinea capitis D. Tinea cruris Answer : C. Tinea capitis 8. What is a common treatment approach for superficial mycoses? A. Systemic antibiotics B. Topical antifungal creams or shampoos C. Radiation therapy D. Chemotherapy Answer : Topical antifungal creams or shampoos  9. Which cells play the most important role in defending against Aspergillus infections? A. B lymphocytes B. T lymphocytes C. Neutrophils and macrophages D. Erythrocytes Answer : C. Neutrophils and macrophages 10. What is a common cause of seborrheic dermatitis? A. Trichophyton rubrum B. Malassezia furfur C. Candida albicans D. Aspergillus fumigatus Answer : B. Malassezia furfur 11. What characteristic lesion is associated with tinea corporis? A. Thickened, discolored nails B. Clearly circumscribed, pruritic, desquamated areas of skin C. Deep tissue nodules and sinuses D. Ulcerated skin nodules answer : B. Clearly circumscribed, pruritic, desquamated areas of skin 12. Which of the following antifungal drugs is known for its nephrotoxicity? A. Terbinafine B. Amphotericin B C. Fluconazole D. Caspofungin Answer : B. Amphotericin B  13.Which fungal infection can cause chronic meningitis if left untreated? A. Histoplasmosis B. Blastomycosis C. Coccidioidomycosis D. Penicillosis Answer : C. Coccidioidomycosis 14. What is the typical clinical manifestation of mucosal candidiasis? A. Painful ulcers B. Skin rashes C. Adherent whitish plaques on mucous membranes D. Hemorrhagic lesions Answer : C. Adherent whitish plaques on mucous membranes 15.Which factor is the most common risk for Pneumocystis jiroveci infection? A. Vitamin D deficiency B. Cellular immunity deficiency C. Excessive exercise D. Iron deficiency Answer : B. Cellular immunity deficiency 16. Which yeast species is responsible for the majority of candidiasis intections? A. Candida glabrata B. Candida parapsilosis C. Candida albicans D. Cryptococcus neoformans Answer : C. Candida albicans  17. What is the characteristic feature of Aspergillus fungi that allows them to invade tissues? A. Production of toxins B. Angioinvasive properties C. Secretion of enzymes D. Formation of spores Answer : B. Angioinvasive properties 18. What is the natural habitat of Histoplasma capsulatum? A. Freshwater lakes B. Human skin C. Ocean water D. Soil with high nitrogen content, often from bird or bat droppings Answer : D. Soil with high nitrogen content, often from bird or bat droppings 19. Which of the following is NOT a common clinical manifestation of sporotrichosis? A. Painless nodular lesions B. Ulceration at the site of inoculation C. Severe systemic symptoms D. Lymphocutaneous nodules Answer : C. Severe systemic symptoms 20. Which fungus is known for causing valley fever? A. Histoplasma capsulatum B. Blastomyces dermatitidis C. Coccidioides immitis D. Paracoccidioides brasiliensis Answer : C. Coccidioides immitis  21. Which superficial mycosis is characterized by hypopigmented or hyperpigmented areas of the skin? A. Tinea cruris B. Seborrheic dermatitis C. Tinea versicolor (Pityriasis versicolor) D. Tinea pedis Answer : C. Tinea versicolor (Pityriasis versicolor) Unit 13 1. Which type of viral genome can be directly translated by the host cell's ribosomes? a) Double stranded DNA b) Single-stranded positive RNA c) Single-stranded negative RNA d) Double stranded DNA Answer : b. Single-stranded positive RNA 2. What is the function of hemagglutinin (HA) in influenza viruses? a) Inhibits host immune response b) Facilitates viral genome replication c) Binding to sialic acid d) Releasing virion offspring from the cell surface Answer : Binding to sialic acid 3. Which virus is known for its ability to establish latent infections in the host cell?  a) Herpes viruses b) Rotavirus c) Coronavirus d) Hepatitis C Answer : Rotavirus 4. What is antigenic shift? a) Minor genetic change which leads to seasonal flu outbreaks b) Major genetic rearrangement creating new viral subtypes which can cause pandemics c) Minor genetic change which lead to pandemics d) Major genetic rearrangement creating new viral subtypes which can cause seasonal flu outbreaks Answer : b. Major genetic rearrangement creating new viral subtypes which can cause pandemics 5. What is the name of the coronavirus responsible for the COVID-19 pandemic? a) MERS-CoV-2 b) SARS-CoV-19 c) SARS-CoV-2 d) COVID-19 Answer : c. SARS-CoV-2 6. Which antiviral drug inhibits viral DNA synthesis by inhibiting viral DNA polymerase: a) Ribavirin b) Acyclovir c) Amantadine d) Interferon Answer : b. Acyclovir 7. Which virus can cause hand, foot and mouth disease? a) Herpes virus b) Morbillivirus c) Coxsackie A virus d) Adenovirus Answer : Coxsackie A virus 8. Which of the following viruses can cause severe congenital infections: a) Influenza virus b) Mumps virus c) Rubella virus d) Adenovirus Answer : c. Rubella virus 9. Which virus is known for its ability to establish Chronic infections in the host cell? a. Herpes viruses b. Rotavirus c. Coronavirus d. Hepatitis C Answer : d. Hepatitis C Unit 14 1. Which virus causes shingles? a) Herpes simplex type 1 b) Herpes simplex type 2 c) Cytomegalovirus d) Varicella-zoster virus Answer : d. Varicella-zoster virus 2. During latency, where does the herpes simplex virus typically reside within the host: a) Epithelial cells b) Sensory ganglion neurons c) Monocytes d) B lymphocytes Answer : Sensory ganglion neurons 3. Which hepatitis virus is known for having multiple genotypes, complicated treatment and difficult vaccine development? a) Hepatitis A virus b) Hepatitis B virus c) Hepatitis C virus d) Hepatitis D virus Answer : Hepatitis C virus 4. What is the most common method of transmission for Epstein-Barr virus? a) Blood transfusion b) Respiratory droplets c) Saliva d) Fecal-oral Answer : c. Saliva 5. Which hepatitis virus is not typically associated with chronic infection? a) Hepatitis A virus b) Hepatitis B virus c) Hepatitis C virus d) Hepatitis D virus Answer : a. Hepatitis A virus 6. Which hepatitis virus has a genome composed of partially double-stranded DNA? a) Hepatitis A virus b) Hepatitis B virus c) Hepatitis C virus d) Hepatitis D virus Answer : b. Hepatitis B virus 7. Which types of Human Papillomavirus (HPV) are most commonly associated with cervical carcinoma? a) HPV 6 and 11 b) HPV 16 and 18 c) HPV 1 and 4 d) HPV 3 and 10 Answer : a. HPV 6 and 11 8. Lesions called „Negri bodies" are pathognomonic for: a) Creutzfeldt-Jakob disease b) Rabies c) Kuru d) Fatal familial insomnia Answer : b. Rabies 1. Which virus causes genital herpes? a) Herpes simplex type 1 b) Herpes simplex type 2 c) Cytomegalovirus d) Varicella-zoster virus Answer : Herpes simplex type 2 2. During latency, where does the Epstein-Barr virus typically reside within the host: a) Epithelial cells b) Sensory ganglion neurons c) Monocytes d) lymphocytes Answer : d. lymphocytes 4. What is the most common method of transmission for varicella- zoster virus? a) Blood transfusion b) Respiratory droplets c) Saliva d) Fecal-oral Answer : b. Respiratory droplets 6. Which hepatitis virus can only infect individuals who are already infected with hepatitis B virus (HBV)? a) Hepatitis A virus b) Hepatitis B virus c) Hepatitis C virus d) Hepatitis D virus Answer : d. Hepatitis D virus 7. Which protein in the HPV virus is primarily responsible for its ability to cause cancer? a) E1 and E2 b) E3 and E4 c) E6 and E7 d) L1 and L2 Answer : c. E6 and E7 1. Which virus causes oral herpes? a) Herpes simplex type 1 b) Herpes simplex type 2 c) Cytomegalovirus d) Varicella-zoster virus Answer : a. Herpes simplex type 1 2. During latency, where does the Cytomegalovirus typically reside within the host: a) Epithelial cells b) Sensory ganglion neurons c) Monocytes d) B lymphocytes Answer : c. Monocytes 4. What is the most common method of transmission for hepatitis A virus? a) Blood transfusion b) Respiratory droplets c) Saliva d) Fecal-oral Answer : d. Fecal-oral 6. Which hepatitis virus is most commonly associated with chronic liver disease and hepatocellular carcinoma? a) Hepatitis A virus b) Hepatitis C virus c) Hepatitis E virus d) Hepatitis F virus Answer : b. Hepatitis C virus 7. Which types of Human Papillomavirus (HPV) are considered to be „low risk" for becoming malignant? a) HPV 6 and 11 b) HPV 16 and 18 c) HPV 1 and 4 d) HPV 3 and 10 Answer : a. HPV 6 and 11