Which of the following allows a limited range of immune cells to detect and respond rapidly to a wide range of pathogens that share common structures?
A. Pattern recognition receptors (PRRs)
B. Cytokines
C. Chemokines
D. T cells .
Pattern recognition receptors (PRRs) are a class of receptors that can directly recognize the specific molecular structures on the surface of pathogens.
PRRs play a crucial role in the proper function of the innate immune system and are germline-encoded host sensors, which detect molecules typical for the pathogens.
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Choice B is incorrect because cytokines are not receptors but rather signaling molecules that regulate immunity.
Choice C is incorrect because chemokines are not receptors but rather signaling molecules that attract immune cells to sites of infection.
Choice D is incorrect because T cells are not receptors but rather white blood cells that assist B cells or directly kill infected cells.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: What is the relationship between viruses and their host cells during replication?
A. Viruses use the host’s replication processes to produce progeny virus particles.
B. Viruses divide inside the host cell to produce progeny virus particles.
C. Viruses have their own replication processes and do not need the host cell.
D. Viruses infect the host cell and destroy it completely.
Answer Explanation
Viruses use the host’s replication processes to produce progeny virus particles.
Viruses are obligate intracellular parasites, meaning that they require a host cell to replicate.
They hijack the host cell’s machinery to produce new virus particles.
Choice B is incorrect because viruses do not divide inside the host cell.
Instead, they use the host cell’s machinery to produce new virus particles.
Choice C is incorrect because viruses do not have their own replication processes and rely on the host cell for replication.
Choice D is incorrect because while some viruses may destroy the host cell during replication, this is not always the case and is not the primary relationship between viruses and their host cells during replication.
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Q #2: A patient with chronic renal failure is undergoing hemodialysis. What process allows for the removal of waste products and excess fluid from the patient's bloodstream during hemodialysis?
A. Active transport.
B. Osmosis
C. Diffusion
D. Facilitated diffusion.
Answer Explanation
Diffusion.
During hemodialysis, waste products and excess fluids are removed from the blood by diffusion 1.
Diffusion is a separation process in which particles that are dissolved in a solution are relocated from an area of higher concentration in the blood to an area of lower concentration in the dialysate.
Choice A.
Active transport is incorrect because active transport is a process that uses energy to move molecules against a concentration gradient.
Choice B.
Osmosis is incorrect because osmosis is the movement of water molecules across a semipermeable membrane from an area of higher water concentration to an area of lower water concentration.
Choice D.
Facilitated diffusion is incorrect because facilitated diffusion is a process where molecules move down their concentration gradient with the help of carrier proteins.
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Q #3: What is the hallmark of adaptive immunity?
A. Rapid recruitment of immune cells to sites of infection and inflammation
B. Antigen-independent defense mechanism
C. Immunologic memory
D. Non-specific host-defense mechanisms .
Answer Explanation
Immunologic memory is the hallmark of adaptive immunity.
Immunologic memory enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen.
Choice A is incorrect because rapid recruitment of immune cells to sites of infection and inflammation is a characteristic of innate immunity.
Choice B is incorrect because antigen-independent defense mechanisms are characteristic of innate immunity.
Choice D is incorrect because non-specific host-defense mechanisms are characteristic of innate immunity.
