Bio 7A

Question 1

What are antigens

Answer 1

Any molecule (protein, sugar, DNA, RNA) that may trigger an immune response
* Free-floating molecules
Do not need to be attached to a pathogen or cell

Question 2

what are the types of antigens

Answer 2

• self antigens and non-self antigens

Question 3

what are self-antigens

Answer 3

antigens that are located on the surface of cells and mark the cells of an organism as ‘self’ so that the immune system does not attack them
- so that the immune system can distinguish self-cells from non-self material
- take the form of MHC markers

Question 4

what are MHC markers

Answer 4

A group of proteins present on the surface of all self-cells that enables the immune system to distinguish it from non-self material
- Differ between individuals

Question 5

what are MHC marker classes

Answer 5

MHC class I:
- expressed on all nucleated cells in the body (NOT red blood cells)
MHC class II:
- are found on specialised cells in the immune system

Question 6

what are non-self antigens

Answer 6

A molecule from outside the body (not belonging to individual) that is recognised by the immune system and initiates an immune response (launch an attack).

Question 7

what are malfunctions involving pathogens?

Answer 7

Autoimmune diseases
- immune system attacks self-cells as it recognises self-antigens as non-self.
Allergic reactions
- antigens that the immune systems recognises as non-self and initiates a strong immune response towards, even though the allergen is non-pathogenic and will not cause harm to the body.

Question 8

what are the types of pathogens

Answer 8

cellular pathogens
- have a cellular structure and are living organisms
non-cellular pathogens
- do not have a cellular structure and are non-living

Question 9

what is the difference between an extracellular and intracellular threat

Answer 9

extracellular threats are found outside of a cell that can interfere with its functioning (e.g. bacteria) whereas intracellular threats are found within a cell that can interfere with its functioning (e.g. virus)

Question 10

when is a disease classified as occurring?

Answer 10

when the pathogens affect the normal functioning of our cells
- e.g. when they produce toxins that cause the lysis of cells, inhibit protein or nucleic acid synthesis, or affect cellular respiration