OBJECTIVE LIFE SCIENCE
SIGNALLING IMMUNOLOGY CANCER
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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They are found on the surface of tissues
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They only kill bacteria
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They destroy pathogens non-specifically
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None of the above
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Detailed explanation-1: -NK cells are called “natural” killers because they can destroy potential threats without prior exposure to a particular pathogen. Other lymphocytes that destroy harmful cells, like cytotoxic T-cells, need previous exposure to a pathogen before they can destroy it.
Detailed explanation-2: -Phagocytosis is a nonspecific defense mechanism in which various phagocytes engulf and destroy the microorganisms of disease. Phagocytes. Among the important phagocytes are the circulating white blood cells called neutrophils and monocytes.
Detailed explanation-3: -Natural killer cells often lack antigen-specific cell surface receptors, so are part of innate immunity, i.e. able to react immediately with no prior exposure to the pathogen.