1. 6.3.1  Define a pathogen?  Disease causing microorganism  Bacteria, Fungi, Virus, Protozoa

2. 6.3.2 Explain why antibiotics are effective against bacteria but not against viruses

3. Antibiotics

4. Common Antibiotics aminoglycosides, chloramphenicol, erythromycin, and clindamycin,

5. Antibiotics against bacteria Bacteria are eukaryotic and body cells are eukaryotic Difference in biochemical reactions and pathway Bacterial cell will contain a cell wall Antibiotics target the bacteria’s biochemical reactions and the bacterial cell wall

6. Antibiotics against virus  How does a virus work  Virus uses body cells to manufacture or make new viruses.  A drug that will target this will also harm the body cells

7. 6.3.2 Explain why antibiotics are effective against bacteria but not against viruses Antibiotics are designed to disrupt structures or metabolic pathways in bacteria and cell walls and membranes DNA synthesis (replication) Transcription Translation These do not exist or are very different in viruses, so the antibiotic will have no effect.

8. 6.3.3 Outline the role of skin and mucous membranes in defense against pathogens

9. 6.3.4 Outline how phagocytic leucocytes ingests pathogens in the blood and in body tissues DetectionIngestionPhagosome formsFusion with lysosomeDigestionDischarge

10. 6.3.5 Distinguish between antigens and antibodies. Antigen – molecule that is recognized by the organism as foreign. It will cause an immune response. Antibody- Immunoglobulin Plasma cell.(WBC) An antibody will recognise an antigen and neutralise it.

11. 6.3.5 Explain Antibody Production Bacteria (containing the antigen) Activation of B cellT helper cell activates b cell B Cell either becomes a plasma cell or memory cell Plasma cell produces antibody Many different types of lymphocyte exist. Each type recognizes one specific antigen and responds by dividing to form a clone. This clone then secretes a specific antibody against the antigen

12. FOR HL  11.1.1  11.1.2  11.1.4  11.1.3  11.1.5

13. 11.1.1Describe the process of blood clotting- animation

14. Challenge and response When a pathogen invades the organism, the immune system is challenged and will produce antibodies against the invading pathogen as a response.

15. Challenge and Response The macrophages (phagocytosis) Macrophage displays antigen (portions of bacterial cell) Once in the lymph nodes – meets with a T(helper) cells Helper T cell contains receptor complimentary to antigen found in the membrane of the macrophage T (helper) cells will be activated and will stimulate B cells to form clones B cell comes in contact with a bacteria that contains an antigen on its surface.

16. Clonal selection  Helper T cell activates a specific B cell  B cell – cell division  Plasma cell  Memory cell

17.  Animation- http://highered.mheducation.com/sites/0072507470/st udent_view0/chapter22/animation__the_immune_respo nse.html

18. Clonal expansion

19. 11.1.4 Explain antibody production.  antigen presentation by macrophages and activation of helper T-cells leading to activation of B-cells which divide to form clones of antibody-secreting plasma cells and memory cells.

20. 11.1.3 Define active and passive immunity.  Active Immunity  immunity due to the production of antibodies by the organism itself after the body’s defense mechanisms have been stimulated by antigens.  Passive Immunity  immunity that is due to the acquisition of antibodies from another organism  placenta, colostrum, or by injection of antibodies.

21. 11.1.5 Describe the production of monoclonal antibodies and their use in diagnosis and in treatment.  inject a mammal (e.g. a mouse) with the antigen  plasma cells will produce antibodies against the antigen  extract the mouse plasma cells  fuse them with B-cell tumor cells  grow in culture and will all produce identical antibodies monoclonal antibodies

22. Monoclonal antibodies used for diagnosis  monoclonal antibodies against the HCG ( hcg is a hormone produced in pregnancy  Fix the antibodies in place on a testing stick/strip.  Add urine to the testing stick/strip.  If the HCG is present in the urine (as it will be if thewoman is pregnant), it will attach to the antibodies.  this will produce a specific colour indicating a positive test.

23. Monoclonal antibodies used for treatment  Various parasitic disease (River Blindness)  Cancer

24. deliberately exposing someone to a weakened/dead/related pathogen develops memory cells against the antigen. bacterial diseases: diphtheria, whooping cough, tetanus; viral diseases: measles, polio, rubella 11.1.6 Explain the principle of vaccination.

25. 11.1.7 Discuss the benefits and dangers of vaccination.  Eradication of some diseases  Fewer people get certain diseases  Prevents disability  polio can cause paralysis and when pregnant women get rubella, the baby's vision may be affected  Herd immunity  many people in a population are vaccinated, the disease will not spread  Overloading the immune system with an antigen will reduce the ability to handle other infections  Other pathogens could grow in the solution with the vaccine.  The vaccine could contain other harmful substances  usually the effect of a mixture of antigens (as in MMR vaccination) is not tested  Side effects of vaccination:  Autism  Brain damage

26. 6.3.7 Outline the effects of HIV on the immune system. It reduces the number of lymphocytes a much lower number of antibodies – likely to get disease. opportunistic diseases people who have been infected with HIV develops AIDS http://www.learner.org/courses/biology/units/hiv/images.html

27. Discuss the cause, transmission and social implications of AIDS.

29. Social implications… stigma and discrimination. Women are more likely to contract HIV from sex with an infected partner than men.-men women inequality parents die because of AIDS- caring for the orphans. Unemployment Use of condoms increases. Lack of education and resources