The class of immunoglobulins most abundant in body is:
- A. IgG
- B. IgE
- C. IgD
- D. IgM
Correct Answer: A
Rationale: The correct answer is A: IgG. IgG is the most abundant class of immunoglobulins in the body, constituting about 75% of total immunoglobulins. IgG plays a crucial role in long-term immunity, neutralizing toxins, and enhancing phagocytosis. IgE is involved in allergic reactions, IgD is mainly found on B cells and functions as a receptor, and IgM is the first antibody produced in response to an infection but is less abundant compared to IgG. Therefore, IgG is the correct choice based on its abundance and diverse functions in the immune system.
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How would you interpret the study results?
- A. Water is safe to be consumed
- B. Water is of doubtful quality
- C. Water is of highly doubtful quality
- D. Water is contaminated
Correct Answer: D
Rationale: Step-by-step rationale:
1. The study results indicate water contamination.
2. Contaminated water poses health risks.
3. Therefore, the correct interpretation is that water is contaminated.
Summary:
- Choice A is incorrect as safety is not confirmed.
- Choice B is too mild given the severity of contamination.
- Choice C is also incorrect, as it does not accurately reflect the study findings.
The bacteria responsible for anthrax is:
- A. Bacillus anthracis
- B. Clostridium tetani
- C. Mycobacterium tuberculosis
- D. Streptococcus pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Bacillus anthracis. This bacterium is known to cause anthrax, a serious infectious disease in humans and animals. Bacillus anthracis is a gram-positive, spore-forming bacterium that produces toxins leading to the characteristic symptoms of anthrax. Clostridium tetani causes tetanus, Mycobacterium tuberculosis causes tuberculosis, and Streptococcus pneumoniae causes pneumonia, none of which are related to anthrax. Therefore, based on the specific pathogen responsible for anthrax, Bacillus anthracis is the correct answer.
Which bacteria are commonly associated with food poisoning?
- A. Clostridium botulinum and Staphylococcus aureus
- B. Bacillus anthracis and Mycobacterium tuberculosis
- C. Treponema pallidum and Neisseria gonorrhoeae
- D. Escherichia coli and Klebsiella pneumoniae
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum and Staphylococcus aureus. Clostridium botulinum produces a potent neurotoxin causing botulism, commonly associated with improperly canned foods. Staphylococcus aureus produces toxins causing symptoms of food poisoning. Bacillus anthracis and Mycobacterium tuberculosis are not typically associated with food poisoning. Treponema pallidum and Neisseria gonorrhoeae are bacteria causing sexually transmitted infections. Escherichia coli and Klebsiella pneumoniae are not directly linked to food poisoning.
How soon do symptoms typically appear after a person is infected with rabies virus
- A. 48 hours
- B. 1 week
- C. 1 month
- D. 1-2 years
Correct Answer: D
Rationale: The correct answer is D: 1-2 years. Rabies has a long incubation period before symptoms appear due to the slow progression of the virus within the body. The virus travels along nerve fibers to the brain, which can take months to years. During this time, the virus replicates and spreads, eventually leading to symptoms. Choices A, B, and C are incorrect as they underestimate the incubation period of rabies. Symptoms typically do not appear as early as 48 hours, 1 week, or 1 month after infection with the rabies virus.
Listeria monocytogenes are:
- A. Gram-negative rod-shaped bacteria
- B. Gram-positive spherical bacteria
- C. Gram-positive rod-shaped bacteria
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C: Gram-positive rod-shaped bacteria. Listeria monocytogenes is a Gram-positive bacterium, as it retains the crystal violet stain during the Gram staining process. The bacteria are rod-shaped, not spherical. Choice A is incorrect as Listeria monocytogenes is not Gram-negative. Choice D is incorrect as Listeria monocytogenes does fall under the category of Gram-positive bacteria. The key is to remember the characteristics of Listeria monocytogenes, which are Gram-positive and rod-shaped.
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