Zusammenfassung der Ressource
The Immune System
- 1) Phagocytes
- 1) Phagocyte recognises the
antigens on a pathogen
- 2) Cytoplasm of phagocyte engulfs pathogen
- Opsonins help as they are molecules in
the blood that attach to foreign antigens
- 3) The pathogen is now
contained in a phagosome in
the cytoplasm of the phagocyte
- 4) A lysosome fuses with the phagosome.
The enzymes break the pathogen down
- 5) The phagocyte then presents
the pathogens antigens. It is now
an antigen presenting cell
- 2) T Lymphocytes
- Type of White Blood Cell
- Surface is covered with receptors
- 1) Receptors bind to antigens on
Antigen-presenting cells
- 2) Each T Lymphocyte has a
different receptor
- 3) When the receptor meets a
complimentary antigen, it binds to it.
This means each lymphocyte is unique
- 4) This activates the
T Lymphocyte
- Clonal Selection
- 5) They then divide to produce clones.
Different types of Lymphocyte have
different functions
- Clonal Expansion
- T Helper
- Release substances to help activate
B Lymphocytes and killer cells
- T Killer
- Kill cells with a virus
- T Regulatory
- Suppress
immune
response
- 3) B Lymphocytes
- Type of White Blood Cell
- Covered with Antibodies
- 1) Antibodies bind to Antigens
- 2) Each Antibody has a different shape
- Unique complimentary
antigen-antibody complex
- 3) This activate the B Lymphocyte
- Clonal Selection
- 4) Divide by mitosis into
plasma and memory cells
- Clonal Expansion
- 4) Plasma cells and Antibodies
- 1) Plasma cells are clones
of B Lymphocytes
- 2) They secrete loads of antibodies
specific to the antigen
- 3) They will bind to the antigen
and form complexes
- Antigen-Antibody Complex
- Variable region is
the binding site
- Hinge region allows
flexibility for binding
- Constant region allows binding to
receptors on immune system cells
- Disulfide bridges hold polypeptide chains together