Nokea
In which of the following GIT infections, the bacteria adhere to the intestine wall and damage the microvilli:
- A. Enteropathogenic E. Coli (EPEC)
- B. Enterohemorrhagic E. Coli (EHEC)
- C. Enterotoxigenic E Coli (ETEC)
- D. Enteroinvasive E Coli (EIEC)
Correct Answer: A
Rationale: The correct answer is A: Enteropathogenic E. Coli (EPEC). EPEC bacteria adhere to the intestine wall using a protein called intimin, leading to microvilli damage. This attachment disrupts the normal absorption function of the intestine.
Summary of why other choices are incorrect:
B: Enterohemorrhagic E. Coli (EHEC) primarily causes bloody diarrhea and does not specifically target microvilli.
C: Enterotoxigenic E. Coli (ETEC) produces toxins that lead to watery diarrhea but does not directly target microvilli.
D: Enteroinvasive E. Coli (EIEC) invades and replicates within intestinal cells, causing inflammatory diarrhea, but does not specifically damage microvilli.
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A pregnant woman applied to a doctor with complaints typical for toxoplasmosis. The doctor took a sample of her blood. What serological tests should be performed in this case?
- A. Complement binding assay
- B. Precipitation test
- C. Neutralization test
- D. Widal's test
Correct Answer: A
Rationale: The correct serological test for diagnosing toxoplasmosis is the Complement Binding Assay (A) because it detects antibodies specific to the Toxoplasma gondii parasite. This test is highly sensitive and specific for toxoplasmosis.
Choice B, Precipitation test, is not used for toxoplasmosis diagnosis but rather for other diseases like syphilis.
Choice C, Neutralization test, is not specific for toxoplasmosis and is used for other types of infections.
Choice D, Widal's test, is used for diagnosing typhoid fever and is not relevant for toxoplasmosis.
In summary, the correct answer (A) is specific to toxoplasmosis, while the other choices are used for different diseases and are not suitable for diagnosing toxoplasmosis.
A specific sequence of three consecutive nucleotides that is part of the genetic code and that specifies a particular amino acid in a protein or starts or stops protein synthesis is called:
- A. Codon
- B. Primer
- C. Nucleosome
- D. Polypeptide
Correct Answer: A
Rationale: Step 1: Definition - A codon is a sequence of three nucleotides that code for a specific amino acid or signal the start/stop of protein synthesis.
Step 2: Function - Codons are essential for translating genetic information into proteins.
Step 3: Specificity - Codons are specific in their role of encoding amino acids.
Step 4: Examples - Examples like AUG for methionine and UAA, UAG, UGA for stop codons illustrate codon functionality.
Step 5: Summary - The correct answer is A (Codon) because it accurately describes the function and specificity of a three-nucleotide sequence in genetic coding. Choices B, C, and D are incorrect as they do not align with the definition and function of a codon.
The causative agent of tuberculosis is:
- A. Mycobacterium leprae
- B. Mycobacterium tuberculosis
- C. Bacillus anthracis
- D. Staphylococcus aureus
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. Mycobacterium tuberculosis is the causative agent of tuberculosis, as it specifically infects the lungs and can spread to other parts of the body. Mycobacterium leprae (Choice A) causes leprosy, not tuberculosis. Bacillus anthracis (Choice C) causes anthrax, not tuberculosis. Staphylococcus aureus (Choice D) is a common bacterium known for causing skin infections, not tuberculosis. Therefore, Mycobacterium tuberculosis is the correct answer for the causative agent of tuberculosis.
Which of the following bacteria is known for causing the disease known as whooping cough?
- A. Bordetella pertussis
- B. Clostridium tetani
- C. Haemophilus influenzae
- D. Staphylococcus aureus
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. This bacterium is known for causing whooping cough due to its ability to produce toxins that damage the respiratory tract, leading to severe coughing fits. Clostridium tetani causes tetanus, Haemophilus influenzae can cause respiratory infections but not whooping cough, and Staphylococcus aureus is more commonly associated with skin infections. Therefore, A is the correct choice based on its specific association with the disease in question.
Protozoan emerging and reemerging diseases generally belong to group:
- A. I
- B. II
- C. III
- D. IV
Correct Answer: A
Rationale: The correct answer is A because protozoan emerging and reemerging diseases fall under Group I according to the classification of infectious diseases by the Centers for Disease Control and Prevention (CDC). Group I includes diseases caused by newly identified or known infectious agents that have increased in incidence or geographic range. Choice B (Group II) includes diseases that have re-emerged due to antimicrobial resistance or lack of previous vaccination. Choice C (Group III) encompasses diseases that can be transmitted from animals to humans, and choice D (Group IV) includes diseases that are caused by re-introduction of eradicated pathogens.