Nokea
Which toxin is specific for ETEC:
- A. TSST-1
- B. Shiga-like toxin
- C. Erythrogenic toxin
- D. LT enterotoxin
Correct Answer: D
Rationale: The correct answer is D: LT enterotoxin. This toxin is specific for Enterotoxigenic E. coli (ETEC) and is responsible for causing diarrhea by increasing cyclic AMP levels in intestinal cells. TSST-1 (choice A) is produced by Staphylococcus aureus, not ETEC. Shiga-like toxin (choice B) is produced by Shigella and EHEC, not ETEC. Erythrogenic toxin (choice C) is produced by Streptococcus pyogenes, not ETEC. Therefore, the LT enterotoxin is the specific toxin associated with ETEC.
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Which of the following statements for measles is NOT true?
- A. It is a childhood infection manifested with exanthema
- B. A characteristic clinical signs are the spots of Koplik
- C. Finding negris bodies is important for diagnosis
- D. Prophylaxis is done via live attenuated vaccine
Correct Answer: C
Rationale: The correct answer is C. Negri bodies are not associated with measles but with rabies. Step 1: Measles is a childhood infection with a rash (A). Step 2: Koplik spots are small white spots on a red base found inside the mouth and are characteristic of measles (B). Step 3: Negri bodies are eosinophilic cytoplasmic inclusions found in neurons infected with rabies virus, not measles (C). Step 4: Prophylaxis for measles is through the MMR vaccine, which is a live attenuated vaccine (D). Therefore, choice C is incorrect as it does not pertain to measles.
Which one is true for the bacterial cell?
- A. The oxidative phosphorylation takes place in the mitochondria
- B. Capsules are essential organelles
- C. Has only DNA but not RNA
- D. Multiplies by binary fission
Correct Answer: D
Rationale: The correct answer is D: Multiplies by binary fission. Bacterial cells reproduce through binary fission, where a single cell divides into two identical daughter cells. This process is essential for bacterial growth and multiplication.
A: The oxidative phosphorylation does not take place in the mitochondria of bacterial cells but in the cell membrane.
B: Capsules are not organelles but outer protective layers found in some bacterial cells.
C: Bacterial cells contain both DNA and RNA, essential for their genetic information and protein synthesis.
Infection of several persons without any epidemiological link is
- A. epidemic
- B. sporadic disease
- C. endemic
- D. pandemic
Correct Answer: B
Rationale: The correct answer is B: sporadic disease. Infection of several persons without any epidemiological link is considered sporadic because it occurs in a random and isolated manner, with no clear pattern or connection between cases. It is not classified as an epidemic (A) because it does not involve a sudden increase in the number of cases within a specific population. It is also not endemic (C) as endemic diseases are constantly present in a particular region or population. Lastly, it is not a pandemic (D) which refers to a global outbreak affecting a large number of people across different countries.
Sanitary and bacteriological examination of air in drug-store premises revealed increased content of sanitary representative microorganisms. What microorganisms are these?
- A. Golden staphylococcus and hemolytic streptococcus
- B. Diphtheria and tuberculosis bacilli
- C. Colon and blue pus bacilli
- D. Epidermal staphylococcus and sarcina
Correct Answer: A
Rationale: The correct answer is A (Golden staphylococcus and hemolytic streptococcus) because these microorganisms are commonly found in the air of contaminated environments like drug-store premises. Golden staphylococcus and hemolytic streptococcus are pathogenic bacteria associated with infections in humans, indicating poor sanitation. The other choices are incorrect because:
B: Diphtheria and tuberculosis bacilli are not commonly found in the air in drug-store premises.
C: Colon and blue pus bacilli are not typical microorganisms associated with air contamination.
D: Epidermal staphylococcus and sarcina are not likely to be present in high amounts in the air of drug-store premises.
Which of the following organelles contain oxidative enzymes capable of oxidizing toxic substances?
- A. peroxisomes
- B. lysosomes
- C. lysosomes
- D. peroxisomes
Correct Answer: D
Rationale: The correct answer is D: peroxisomes. Peroxisomes contain oxidative enzymes, such as catalase and peroxidase, that are capable of oxidizing toxic substances. These enzymes help detoxify harmful molecules by breaking them down into harmless products. Lysosomes (choices B and C) contain hydrolytic enzymes for breaking down cellular waste, not oxidative enzymes. Therefore, the correct choice is peroxisomes due to their specific function in detoxification through oxidation reactions.