Nokea
The bacterial genome is typically composed of:
- A. double-stranded RNA
- B. linear DNA
- C. circular double-stranded DNA
- D. single-stranded DNA
Correct Answer: C
Rationale: The correct answer is C: circular double-stranded DNA. Bacterial genomes are typically composed of circular double-stranded DNA due to its stability and efficient replication. Circular DNA allows for continuous replication without the need for telomeres present in linear DNA (choice B). Bacteria do not typically have double-stranded RNA genomes (choice A) as RNA is more commonly found in viruses. Single-stranded DNA (choice D) is not typically the main genetic material in bacteria, as it is less stable and less efficient for information storage compared to double-stranded DNA.
You may also like to solve these questions
What preparations are used for prevention of fungal infection?
- A. Fluconozol, Orungal, Nisoral
- B. Rubomycin, Bleomycin, Mytomycin C
- C. Cytosar, Cormyctin, Lomycitin
- D. Captopril, Enalapril
Correct Answer: A
Rationale: The correct answer is A because Fluconazole, Orungal, and Nizoral are antifungal medications commonly used for prevention of fungal infections. Fluconazole is a systemic antifungal agent, Orungal (Itraconazole) is used for various fungal infections, and Nizoral (Ketoconazole) is effective against a wide range of fungal infections. Choices B, C, and D do not contain antifungal medications and are unrelated to preventing fungal infections.
Which of the following bacteria is responsible for causing the disease known as whooping cough?
- A. Bordetella pertussis
- B. Clostridium tetani
- C. Haemophilus influenzae
- D. Staphylococcus aureus
Correct Answer: A
Rationale: Step 1: Bordetella pertussis is the causative agent of whooping cough, also known as pertussis.
Step 2: This bacterium produces toxins that damage the respiratory tract, leading to severe coughing fits.
Step 3: Clostridium tetani causes tetanus, Haemophilus influenzae causes respiratory infections, and Staphylococcus aureus causes skin infections.
Step 4: Therefore, A is the correct answer as it is the only bacterium directly associated with whooping cough.
A gynaecologist was examining a patient and revealed symptoms of genital tract inflammation. A smear from vagina contains pyriform protozoa with a spine, flagella at their front; there is also an undulating membrane. What disease can be suspected?
- A. Urogenital trichomoniasis
- B. Lambliasis
- C. Intestinal trichomoniasis
- D. Toxoplasmosis
Correct Answer: A
Rationale: The correct answer is A: Urogenital trichomoniasis. The presence of pyriform protozoa with a spine, flagella at their front, and an undulating membrane in a vaginal smear indicates Trichomonas vaginalis, the causative agent of urogenital trichomoniasis. Trichomonas vaginalis is sexually transmitted and causes vaginal discharge, itching, and inflammation. Lambliasis (choice B) is caused by Giardia lamblia, which is not characterized by the described features. Intestinal trichomoniasis (choice C) is caused by a different species, Tritrichomonas foetus, and presents with diarrhea in cattle. Toxoplasmosis (choice D) is caused by Toxoplasma gondii and typically affects the brain and other organs, not the genital tract.
Microscopic examination of a smear from a patient with diphtheria revealed dark blue-staining granules at the ends of rod-shaped bacteria. What staining technique was likely used?
- A. Neisser's staining
- B. Ziehl-Neelsen staining
- C. Gram staining
- D. Giemsa staining
Correct Answer: A
Rationale: The correct answer is A: Neisser's staining. Neisser's staining is used to detect metachromatic granules in bacteria, which appear as dark blue-staining granules at the ends of rod-shaped bacteria in diphtheria. This technique specifically targets these granules, making it ideal for identifying Corynebacterium diphtheriae, the causative agent of diphtheria. Ziehl-Neelsen staining is used for acid-fast bacteria like Mycobacterium tuberculosis, Gram staining is for classifying bacteria based on cell wall composition, and Giemsa staining is used for detecting parasites and certain blood cells, making them incorrect for identifying granules in diphtheria.
Adenoviral infections are restricted only to the upper respiratory tract:
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on circumstances
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: FALSE. Adenoviral infections are not restricted only to the upper respiratory tract; they can also affect the gastrointestinal tract, eyes, and other organs. Adenoviruses are known to cause a wide range of illnesses beyond just respiratory infections. Therefore, option B is correct. Option A is incorrect because it states that adenoviral infections are restricted to the upper respiratory tract, which is not true. Option C is incorrect because there is no circumstance where adenoviral infections are solely limited to the upper respiratory tract. Option D is also incorrect as the correct answer is B.