Cell Recognition And The Immune System Flashcards
What are antigens?
A toxin or other foreign substance which induces an immune response in the body especially the production of antibodies.
What is the first stage of phagocytosis?
The phagocyte is attracted to the pathogen by chemoattractants. it moves along a concentration gradient towards the pathogen.
What is the second stage of phagocytosis?
The phagocyte binds to the pathogen.
What is the third stage of phagocytosis?
Lysosomes within the phagocyte migrate towards the phagosome, formed by engulfing the bacterium.
What is the fourth stage of phagocytosis?
Lysosomes release there lytic enzymes into the phagosome, where they break down the bacterium.
What is the fifth stage of phagocytosis?
The breakdown products of the bacterium are absorbed by the phagocyte.
What is the function of phagocytes?
Engulf any foreign material that has entered the body.
What is the first stage of T cells responding to a foreign antigen?
A phagocyte has engulfed a pathogen and displays the antigen on its surface.
What is the second stage of T cells responding to a foreign antigen?
The antigen is displayed to many different T cells in the lymph nodes.
What is the third stage of T cells responding to a foreign antigen?
clonal selection. Stimulated T cell divides many times (mitosis)
What is the fourth stage of T cells responding to a foreign antigen?
Helper T cells secrete chemicals which stimulate phagocytic cells, stimulate B cells to produce antibodies and activate killer T cells.
What is the fifth stage of T cells responding to a foreign antigen?
Killer T cells bind to cells presenting the complementary antigen.
What is the sixth stage of T cells responding to a foreign antigen?
killer T cells bind to cells presenting the complimentary antigen and kill them.
What is the seventh stage of T cells responding to a foreign antigen?
T memory cells formed after infection.
Where do T lymphocytes respond to foreign material?
inside body cells
Where do T lymphocytes mature?
in Thymus gland
Where do B lymphocytes mature?
bone marrow
What are T lymphocytes involved in?
cell-mediated immunity
What are B lymphocytes involved in?
humoral immunity
What do T lymphocytes respond to?
own cells altered by viruses or cancer and to transplanted tissues
What do B lymphocytes respond too?
bacteria and viruses , foreign material outside the body.
What is the first stage of B lymphocytes responding to a foreign antigen?
cells with the right shape of receptors for antigen is stimulated by T helper cells to divide by mitosis.
Once B cells have divided what happens?
B memory cells remain until second infection occurs. Plasma cells secrete antibodies.
What do antibodies cause?
Pathogens to clump together. This renders them harmless and prepares them for destruction.
How does the structure of antibodies allow them to carry out their function?
Antigen binding site - 3D shape is specific to one type of antigen and allows the antibody to attach due to the complementary shape.
Variable region has a specific sequence of amino acids in the polypeptide chain which causes the shape of the antigen binding site to be specific to complimentary substrate.
What are monoclonal antibodies?
Antibodies that are specific to one type of antigen because they are produced from a single plasma cell that has undergone repeated mitosis.
