IMMUNITY- vaccination,HIV,antibodies in medicine etc

Question 1

explain the principles of vaccination?

Answer 1

vaccine contains dead/inactive version of pathogen or antigen.
triggers primary immune response
memory cells are produced and remain in the blood stream
when second infection occurs with the same pathogen, the secondary immune response is rapid and produces higher concentration of antibodies
pathogen is destroyed before it causes symptoms

Question 2

what is herd immunty?

Answer 2

vaccinating large proportion of population reduces available carriers of pathogen. protects individuals who have not been vaccinated eg. people with weak immune system

Question 3

what are some ethical issues surrounding the use of vaccines?

Answer 3

• production may involve use of animals - animal testing
• potentially dangerous side effects
• clinical tests may be fatal

Question 4

describe the structure of HIV?

Answer 4

• 2 x RNA genetic material and viral enzymes ( reverse transcriptase) surrounded by capsid
• surrounded by viral envelope which is derived from the hosts cells membrane
• GP120 attachments proteins on surface

Question 5

How does HIV result in the symptoms of AIDS?

Answer 5

1. The attachments proteins bind onto the complementary CD4 receptors on the T-Helper cells
   2.HIV protein capsule then fuses with the T-Helper cells membrane, enabling RNA and enzymes from HIV to enter
   3.HIV particles replicate inside the T-Helper cells, killing or damaging them
   4.AIDS develops when there is too few T-Helper cells for the immune system to function
2. Individuals cannot destroy other pathogens and suffer from secondary diseases and infections.

Question 6

why are antibiotics ineffective against viruses?

Answer 6

antibiotics often work by damaging murein cell walls to cause osmotic lysis. viruses have no cell wall
viruses replicate inside host cells = which is difficult to destroy without damaging normal body cells.

Question 7

symptoms of aids?

Answer 7

Minor infections, respiratory infections, decreased immunity, chronic diarrhoea, bacterial infections, tuberculosis.

Question 8

suggest clinical applications of monoclonal antibodies?

Answer 8

• pregnancy test by detecting HCG hormones in urine
• diagnostic procedures eg ELISA test
• targeted treatment by attaching drugs to antibody so it binds to cells with abnormal antigen. eg cancer cells due to specificity of tertiary structure of binding sites.

Question 9

explain the principle of an indirect ELISA test?

Answer 9

1. Add a test sample from a patient to the base of the beaker.
   2 wash to remove any unbound test sample.
2. Add any antibodies complimentary to the shape of the antigen you are testing the presence of
3. Wash to remove any unbound antibodies.
4. Add a second antibody complimentary to the first antibody which binds to it.
5. The second antibody has the enzyme attached to it.
6. Substrate to the enzyme which is colourless is added.
7. The colour change indicate presence and intensity of the antigen.

Question 10

suggest some ethical issues surrounding the use of monoclonal antibodies?

Answer 10

• production involves animals (mice spleen removed)