Which one is NOT included in the non-specific immune response

Correct Answer: B

Rationale: Memory cells are not part of the non-specific immune response because they are a component of the specific immune response. Non-specific immune responses are immediate and target a broad range of pathogens, whereas memory cells are formed after exposure to a specific pathogen to provide a quicker and stronger response upon subsequent exposure. Lysozyme (A), Interferon (C), and Phagocytosis (D) are all part of the non-specific immune response. Lysozyme is an enzyme that destroys bacterial cell walls, interferon helps to inhibit viral replication, and phagocytosis involves the engulfing and destruction of pathogens by phagocytes. These responses are not specific to particular pathogens and are the body's first line of defense.

Correct Answer: D

Rationale: The correct answer is D because during the incubation period of Salmonella Typhi infection, the bacteria multiply in the macrophages of the Peyer's patches and solitary follicles. This is supported by the fact that S. Typhi is an intracellular pathogen that targets the lymphoid tissues of the intestines. Macrophages in these areas serve as the primary host cells for the bacteria, allowing for their replication and evasion of the host immune response. Choices A, B, and C are incorrect because S. Typhi does not primarily multiply in the small intestine enterocytes, the lumen of the small intestine, or hepatocytes during the initial stages of infection.

Correct Answer: A

Rationale: The correct answer is A: Staphylococcus aureus. This is because Staphylococcus aureus is Gram-positive, catalase-positive, and coagulase-positive, which matches the characteristics described in the question. Staphylococcus epidermidis is also Gram-positive but is coagulase-negative. Streptococcus pneumoniae is Gram-positive but is catalase-negative. Enterococcus faecalis is Gram-positive but is catalase-negative and coagulase-negative. Therefore, based on the given information, Staphylococcus aureus is the likely causative agent of the wound infection.

Correct Answer: B

Rationale: The correct answer is B, Antony van Leeuwenhoek. He was the first to observe and describe "animalcules" (microorganisms) through his early microscopes. Robert Hooke (A) is known for his work with cells but did not discover animalcules. Hans Janssen (C) and John Needham (D) did not make significant contributions to the discovery of microorganisms. Leeuwenhoek's pioneering observations were crucial in the development of microbiology.

Correct Answer: C

Rationale: Rationale: 1. Bacillus anthracis and Clostridium tetani are both spore-forming bacteria. 2. Spores allow them to survive harsh conditions like extreme heat or lack of nutrients. 3. Choice C is correct because both A and B (Bacillus anthracis and Clostridium tetani) produce spores. 4. Choice D is incorrect as both bacteria mentioned are known to produce spores, enabling them to survive in extreme conditions.

Correct Answer: A

Rationale: The correct answer is A: decompose hydrogen peroxide. Catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen. This is important in bacteria to protect them from the harmful effects of hydrogen peroxide, a byproduct of metabolism. Choice B is incorrect as peptidoglycan synthesis is not the function of catalase. Choice C is incorrect as oxidative phosphorylation is a metabolic process unrelated to catalase function. Choice D is incorrect as endotoxin production is not a role of catalase.

Correct Answer: A

Rationale: The correct answer is A: Doxycycline. It is a broad-spectrum antibiotic effective against a wide range of bacteria, including those causing infections like Lyme disease and pneumonia. Doxycycline is often the first-line treatment for these infections due to its efficacy and low risk of resistance. Chloramphenicol (B) has serious side effects and is reserved for specific cases. Penicillin (C) is not effective against all bacteria and may not cover the specific infection. Streptomycin (D) is mainly used for certain types of bacterial infections and is not the optimal choice for the conditions mentioned in the question.

Correct Answer: A

Rationale: The correct answer is A because significant bacteriuria is defined as having more than 10^5 cells in 1 ml of midstream morning urine. This concentration indicates a true infection rather than contamination. Choice B is incorrect because the amount of urine does not determine significant bacteriuria. Choice C is incorrect because even a single bacterium in urine does not necessarily indicate an infection. Choice D is incorrect because not all statements are correct; only choice A accurately defines significant bacteriuria based on the bacterial concentration in urine samples.

Correct Answer: A

Rationale: The correct answer is A: Escherichia coli. Step-by-step rationale: 1. Gram-negative rods: E. coli is a Gram-negative rod bacterium. 2. Fermented lactose: E. coli is known to ferment lactose. 3. Common cause of diarrhea: E. coli is a common causative agent of infectious diarrhea. Summary: B: Salmonella typhi causes typhoid fever, not typically associated with lactose fermentation. C: Shigella dysenteriae causes dysentery, not known for lactose fermentation. D: Proteus vulgaris is not a common cause of infectious diarrhea and does not typically ferment lactose.