BIO 101 Fall2010 Exam#2 Review

BIO 101 Fall2010 Exam#2 Review - Chap. 24. The Immune...

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Chap. 24. The Immune System This chapter describes how the human body protects itself from microbes in the environment. It also describes how the body fights infections and disease. Lectures 1 and 2 Outline : Some terminology is defined below: antigen - Any molecule that is foreign to a white blood cell and triggers an immune response . An antigen is usually a protein or polysaccharide on the surface of a virus or foreign cell , etc. Each person has a specific set of self markers unique for that person (identical twins have the same markers). Self markers (also called self proteins) introduced into another person are foreign to that person's white blood cells and are called antigens - their presence triggers an immune response. Major histocompatibility complex (MHC) - a genetic term referring to the genes that code for the proteins that compose the self markers on the cell membrane. antibody - An antibody is a " Y " (or sometimes "T") shaped receptor molecule with a binding cite for a specific antigen so that it can be tagged for destruction. Antibodies are proteins that react against foreign substances, they attach to a portion of the antigen (epitope) and counter its effects. An antibody is composed of 4 polypeptide chains held together by disulfide bridges , 2 chains are long - called "heavy chains" and 2 are short - called "light chains". All 4 chains have constant (C) regions and variable (V) regions. The "V" recognizes and binds to the epitope while the "C" destroys the antigen . The antigen-binding site is the region of the antibody that binds to the epitope of the antigen: see p.491 Fig.24.6. Note: The epitope (also referred to as the antigenic determinant) is the portion of an antigen recognized by the antibody . The epitope fits the antibody like a key fits a lock. distinguished by tips millions of dif kinds of antibody because of millions of antigen immunity - Resistance to a specific microbe (invader) obtained by having an infection or by vaccination (when the body receives a harmless form of the disease causing microbe as with the viral diseases polio, measles, smallpox and mumps). active immunity - When you make the antibodies yourself . Obtained when antigens enter the body naturally (ex. catching the flu ) or artificially ( getting a flu shot which contains a harmless form of the virus). The vaccine supplies the antigens and the body responds by making antibodies. Active immunity can last many years, perhaps a lifetime. passive immunity - When you receive the antibodies (your body does not synthesize the antibodies). Ex. Pregnant woman passes antibodies to her fetus. After birth, breast milk also provides antibodies. At best, passive immunity lasts no longer than a few months. complement proteins
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This note was uploaded on 02/10/2011 for the course BIO 101 taught by Professor Martin during the Fall '08 term at Rutgers.

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BIO 101 Fall2010 Exam#2 Review - Chap. 24. The Immune...

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