Nokea
Which of the following bacteria is responsible for causing tuberculosis?
- A. Mycobacterium leprae
- B. Mycobacterium tuberculosis
- C. Streptococcus pneumoniae
- D. Neisseria gonorrhoeae
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium tuberculosis. This bacterium is responsible for causing tuberculosis. Mycobacterium leprae (choice A) causes leprosy, not tuberculosis. Streptococcus pneumoniae (choice C) is known for causing pneumonia, not tuberculosis. Neisseria gonorrhoeae (choice D) is responsible for causing gonorrhea, not tuberculosis. Mycobacterium tuberculosis is the specific bacterium associated with tuberculosis due to its ability to infect the lungs and other organs, leading to the characteristic symptoms of the disease.
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Which of the following statements about in vitro cultivation of viruses is true?
- A. Viral cultivation under laboratory conditions is impossible
- B. Viruses are cultured on hen embryos, cell cultures and experimental animals
- C. Viruses are cultivated on special nutrient media
- D. Viruses are cultured only in human embryonic cell cultures
Correct Answer: B
Rationale: The correct answer is B because viruses can indeed be cultured on hen embryos, cell cultures, and experimental animals in vitro. This method allows for the replication and study of viruses outside the host organism. Option A is incorrect as viral cultivation is possible in laboratory settings. Option C is incorrect because while viruses can be grown on nutrient media, it is not the only method. Option D is incorrect as viruses can be cultured in various types of cell cultures, not just human embryonic ones.
Poxviruses are the largest viruses, almost visible on a light microscope.
- A. TRUE
- B. FALSE
- C. Not Sure
- D. Partially
Correct Answer: A
Rationale: The correct answer is A: TRUE. Poxviruses are indeed the largest viruses, ranging from 200-450 nm in size, which is close to the resolution limit of a light microscope. This makes them almost visible under a light microscope. The other choices are incorrect because poxviruses are not smaller or uncertain in size (choices B and C), nor are they partially visible - they are almost visible due to their relatively large size.
Bypass fume hoods belong to the group of
- A. general-purpose hoods.
- B. radioisotope hoods.
- C. perchloric acid hoods.
- D. biosafety cabinets.
Correct Answer: A
Rationale: The correct answer is A: general-purpose hoods. Bypass fume hoods are designed to handle a wide range of chemical fumes and vapors, making them suitable for various types of experiments and processes. They are not specifically designed for radioisotopes (B), perchloric acid (C), or biological materials (D). Therefore, A is the correct choice for bypass fume hoods.
Which of the following is a feature of Gram-negative bacteria?
- A. Thick peptidoglycan layer
- B. Outer membrane with lipopolysaccharides
- C. Presence of teichoic acids
- D. Absence of a cell wall
Correct Answer: B
Rationale: The correct answer is B: Outer membrane with lipopolysaccharides. Gram-negative bacteria have an outer membrane containing lipopolysaccharides (LPS), which are important in pathogenesis and immune response. This feature is unique to Gram-negative bacteria, distinguishing them from Gram-positive bacteria (choice A). Teichoic acids (choice C) are found in the cell walls of Gram-positive bacteria, not Gram-negative. The statement in choice D, absence of a cell wall, is incorrect as all bacteria have a cell wall, although the composition may vary between Gram-negative and Gram-positive bacteria.
Which of the following bacteria is known to cause strep throat?
- A. Streptococcus pyogenes
- B. Staphylococcus aureus
- C. Neisseria gonorrhoeae
- D. Clostridium tetani
Correct Answer: A
Rationale: Step 1: Streptococcus pyogenes is commonly known as Group A Streptococcus, which is the primary bacteria responsible for causing strep throat.
Step 2: Staphylococcus aureus is not typically associated with strep throat but can cause skin infections and other illnesses.
Step 3: Neisseria gonorrhoeae is the bacteria responsible for gonorrhea, a sexually transmitted infection, not strep throat.
Step 4: Clostridium tetani causes tetanus, a bacterial infection that affects the nervous system and is not related to strep throat.