Biology Unit 1

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  • Created by: Abigail
  • Created on: 07-01-13 17:59
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  • A pathagen is an organism that causes disease.
    • Cause of disease
      • Produces toxins that are harmful to the body.
      • Cell Damage- Rupturing to release nutrients. Breaking down nutrients for own use. Replicating inside cells and bursting them to release.
  • Vaccines.
    • Whilst B-cells are dividing, you are suffering from the disease. Vaccines contain antigens that cause the body to produce memory cells to deal with the pathogen causing immunity and no symptoms.
    • Antigenic variation. Pathogen has different antigens on the second attack. Memory cells do not recognise and so symptoms occur.
  • Monoclonal Antibodies. Produced form a single group of genetically identical B-cells produced to target specific substances or cells.
    • The Immune system
      • Stage 1) A phagocyte is a type of white blood cell that carries out phagocytosis. Engulfing the pathogen. They are found in blood and tissues. The phagocyte recognises the antigens on the pathogen and engulfs it. The pathogen is contained in a vacuole in the cytoplasm. A lysosome breaks down the pathogen and the phagocyte presents the antigens to activate other immune cells.
        • Phagocytes Activate T-cells- The T-cell has protiens on it's surface that bind to the antigens presented on the phagocyte. Some then release substances to activate B-cells whereas some attach to the antigen on the pathogen and kill the cell.
          • T-cells activate B-cells. B-cells are covered with antibodies (protiens that bind with antigens) to form an antigen antibody complex. Each B-cell has a different shaped antibody on the membrane. The antibody on the B-cell meets a complementary shaped antigen and binds to it. This, together with the substances released by T-cells activate the B-cells. The B-cells divide into plasma cells.
            • Plasma cells are clones to the B-cells and secrete antibodies specific for that antigen. Antibodies coat the pathagens to make it easier for the phagocyte to engulf it. It also makes the pathogen unable to enter host cells and neutralises toxins.
      • Vaccines.
        • Whilst B-cells are dividing, you are suffering from the disease. Vaccines contain antigens that cause the body to produce memory cells to deal with the pathogen causing immunity and no symptoms.
        • Antigenic variation. Pathogen has different antigens on the second attack. Memory cells do not recognise and so symptoms occur.

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