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A Level Biology - Section 2: Cells - Coggle Diagram
A Level Biology - Section 2: Cells
Chapter 5 - Cell recognistion and immune systems
5.5: Vaccinations
Passive immunity occurs when antibodies are introduced into the body with no contact with the infectious pathogen. This means that plasma and memory cells aren't used
This fails to provide
long term immunity
This occurs when a mother breast feeds her child and the maternal antibodies are passed to the baby through either breast milk or the placenta
Active immunity occurs differently, your immune system produces a response once it has encountered the pathogen or its antigen
NATURAL VS ARTIFICAL
Following the introduction of a weakened version of the pathogen or antigen via a vaccine
Natural: Following infection and creation of won antibodies and memory cells
Herd Immunity occurs when enough of the population have been vaccinated so that spread between the population is unlikely. This helps people who can't get the vaccine i.e. elderly
5.6: HIV
Viruses are forced to replicate inside of cells as they aren't living so they have no other mechanism to reproduce
This makes it hard for the immune system to fight off viral infections and they don't have a cell wall like bacteria so antibiotics are useless
Structure of Virus
Core = Contains the genetic material and the enzyme reverese transcriptinase which is needed for viral replication
(Nucleo) Capside = Outer protein coat
Envelope = Additional outer layer, made out the membrane from the host's cells
Protein Attachment = On the exterior of the envelope they exist to help the virus attach to the host's helper T cells
HIV replication
1.) HIV is transported around the blood until it attaches to a protein on a helper T cell
2.) The HIV protein capsule and cell membrane of the helper T cell fuses which allows the RNA and enzymes to enter into the cell
3.) The HIV reverse transcriptinase enzyme, copies the viral RNA into DNA which moves into the helper T cell
4.) Here the mRNA is transcribed, which forces the Helper T cell to create viral proteins and make new viral particles
AIDS
AIDS occurs when the replicating viruses in the helper T cells interfere with the person's natural immune system. As the helper T cells are destroyed the immune system struggles to mount a sufficent immune response and therefore is susceptible to infections
AIDS is more likely to be the cause of someones death rather than the direct cause (therefore the SYNDROME)
Symptoms
Encephalitis
Menigitis
Tumors
T.B
Pneumonia
5.7: Monoclonal Antibodies
A single type of antibody which can be isolated and then cloned, antibodies are proteins which have a complementary shape to specific antigens
Monoclonal antibodies are used for...
Medical treatment
Medical diagnosis
Pregnancy tests
Direct monoclonal antibody therapy
Certain cancer can be treated by using monoclonal antibodies which bind to the antigens on the outside of the cancer cells which are complementary in shape
Once the antibodies are given to the patient they attach to the antigens on the cancer cells, which means that certain chemicals cannot attach to the cancer cells
The monoclonal antibodies are advantageous as they can bind to the cancer cells and prevent them from growing whilst not causing harm to any other cells
Indirect Monoclonal Antibody therapy
These cancer drugs are delivered straight to the cancer cells which mitigates the harmful effect that traditional healthcare (chemotherapy) provices
This method of treatment is known as 'bullet drugs'
Cancer can also be treated with complementary monoclonal antibodies by having them attach to antigens with drugs attached to them
ELIZA test
Enzyme linked immunosorbent assay
First mobile antibody is complementary to the antigen being tested (this has a coloured dye attached)
A second antibody complementary in shape to the antigen is then immobilised in the test
A third antibody is immobilised and is also complementary in shape to the first antibody
Method (ELIZA)
Add the test sample from the patient to the base of a beaker
Wash to remove any unbound test sample
Add an antibody complementary in shape to the antigen you are testing the presence of in the sample
Again wash to remove any unbound antibody
Add a second antibody which is complementary in shape to the first antibody and binds to it. The second antibody will have an enzyme attached
The substrate required for the enzyme is added (it's colourless) This substrate produces coloured products in the presence of the enzyme
The presence of the colour indicates the presence of the antigen and the intensity of the colour indicates the quantity
