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Living Environment Regents August 2010 Question 19 |
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NYS Living Environment Regents August 2010
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Correct answer: (1) foreign antigens
Antigens are foreign molecules that do not belong to the host organism and that elicit an immune response. Pathogens, such as viruses and bacteria, are the usual antigens encountered by the body. When an organ is transplanted from another individual (donor), some of the molecules in that organ may be recognized as foreign and harmful by the host's immune system. Thus, drugs are necessary to suppress the immune system from recognizing the components of the new organ as antigen.
Incorrect answers:
(2) foreign antibodies
Antibodies are antigen-binding immunoglobulins produced by the B cells that function as the effectors in an immune response. Antibodies are formed after the immune system recognizes the presence of an antigen. The immune system will only form antibodies in the donated organ once the system recognizes the presence of antigens.
(3) DNA molecules
The organ is composed of body cells that contain the DNA. However, the expression (the term "expression" seems awkward. Is this a jargon?) of the genes in the DNA do not elicit an immune response.
(4) pathogenic microbes
Pathogenic microbes are considered as antigens. When organs are transplanted from one body to another, the donor undergoes procedures that ensures that the organ for donation do not contain any pathogens that will be harmful to the host.
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