AQA AS unit 1 notes on the immune system and immunology

AQA, unit 1 

includes full notes on immunology, pathogens and the immune system

this is a tricky topics for me and so I used all the sources available to me to compile these notes

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The Immune system
1. Pathogens cause infectious disease:

A pathogen is an organism that causes disease. The pathogen could be a micro-organism (bacteria, viruses
or fungi) or other organisms (tapeworm)

2. Pathogens enter the body by:

Break in the skin

3. How pathogens effect the body:


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6. Non-specific responses:

Outside Inside

Barrier (eg. Skin) Blood clot Pathogens inside
the body
Pathogens (eg. Bacteria)

Lysosome in sweat Inflammation Phagocytosis

7. Immune response

Body temperature rises ­ damages pathogenic cells
Inflammation ­ due to the blood vessels in the affected area become more permeable and…

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B-cells release antibodies
Antibodies attack the pathogen

10. Phagocytes activate t-cells:

A t-cell is another type of white blood cell
It has complementary antibodies on the surface that bind to the antigens (from phagocytosis)

What the t- cells do:

Divide by mitosis to form clones
Release substances to activate the…

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13. Primary and Secondary response:

An antigen enters the body for the first time
Activates the immune system ­ primary response
There aren't many b-cells so few antibodies can bind to them and so it's slow
Eventually the b-cells are replicated into plasma cells and so there are enough antibodies…

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15. Vaccinations:

Vaccines contain either a pathogen or their antigens
They stimulate primary response so that when the actual pathogen is encountered, the secondary
response is strong enough to prevent the disease developing

Types of vaccine:

Live vaccines
The pathogens in the vaccine are treated so they only divide a…

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They are produced from a single group of genetically identical b-cells (plasma cells)
They are very specific (their binding sites have a unique structure that only one antigen will be
complementary to)
They will bind to anything ­ an antigen or another substance as they will target and only bind…




Really helpful just a lot of spelling mistakes

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