Biology Unit 1 Booklet 6 Flashcards
What is an antigen (2)
Protein molecule (1) That causes T or B cell production/ antibody production (1)
Ways in which pathogens cause disease (2)
Produces toxins (1) Causes damage to cells and tissues (1)
Differences between specific and non-specific response (4)
Non-specific mechanism do not distinguish between one type of pathogen and another but responds in the same way (1)
E.g. Barrier to entry of pathogens or phagocytosis (1)
Specific mechanism distinguish between different types of pathogen and provide longer lasting immunity (1)
E.g. Cell mediated response involving T lymphocytes or humoral response involving B lymphocytes (1)
Barriers to pathogen entry (3)
Protective covering if the body e.g. Skin (1)
Epithelia are covered in mucus (1)
Hydrochloric acid in the stomach (1)
Difference between B cells and T cells (2)
B cells mature in bone marrow (1)
T cells mature in the thymus gland (1)
Process of phagocytosis (6)
Chemical product of the pathogen acts as an attractant, causing phagocytes to move towards the pathogen (1)
Phagocytes attach themselves to the pathogen surface (1)
Phagocytes engulf pathogen to form a vesicle- phagosome (1)
Lysosomes move towards the vesicle and fuse with it (1)
Enzymes within the lysosomes break down pathogen by hydrolysis (1)
Soluble products from the breakdown of the pathogen are absorbed into the cytoplasm of the phagocytes (1)
Key events of cell mediated immunity (6)
Pathogens are taken on by antigen presenting cells e.g. Phagocytes (1)
Phagocyte presents antigens from the pathogen in its cell surface membrane (1)
Receptor on certain T helper cells fit exactly onto these antigens (1)
This activates other T cells to divide rapidly by mitosis and form a clone (1)
Cloned T cells can then develop into memory cells (1)
Or stimulate phagocytes to engulf pathogens by phagocytosis; simulates T cell to divide; kill infected cells (1)
Key events of humoral immunity (7)
Surface antigens of invaded pathogen are taken up by macrophage (1)
Macrophage process the non self antigens and display them on their own self surface membrane ( antigen presentation ) (1)
T helper cells attach to the processed antigens on the macrophage and activate them (1)
B cells are activated to divide by mitosis to produce palms cell clones (1)
Clone plasma cells produce antibodies complementary to antigens on pathogen surface (1)
Antibodies attach to antigens and destroy them (primary response) (1)
Some B cells develop into memory cells and can respond to future infections ( secondary response ) (1)
Antigenic variability (3)
Some pathogens have different strains - the antigens keep changing (1)
Shape of antigen does not correspond to antibodies formed in previous infections (1)
Therefore no appropriate memory cells to stimulate antibody production (1)
Production of monoclonal antibodies (6)
Mouse is exposed to non self material (1)
B cells in mouse produce mixture and polyclonal antibodies, which are then extracted from the spleen (1)
These are mixed with cells that can rapidly divide outside the mouses body e.g. Tumour cells. This enables the B cells to divide (1)
Detergent is added to break down cell membranes and enable fusion (1)
Few cells are separated and each single cell is cultured form a clone (1)
Any clone producing the required antibodies grown on a large scale antibodies are extracted from the growth medium (1)
Explain why these are referred to as monoclonal (1)
They are antibodies that are produced from a single clone of B (plasma) cells (1)
Why tests involving monoclonal antibodies are specific (3)
They have specific sequence of amino acid in their primary structure (1)
So this generates a specific tertiary structure (1)
Only bind to antigens that have a complementary shape (1)
Functions if monoclonal antibodies (4)
Separation of a chemical from a mixture (1)
Immunoassay (1)
Cancer treatment (1)
Transplant surgery (1)
What is a vaccine (2)
A weakened (attenuated) form of a pathogen/ microorganism (1) That stimulates the production of antibodies / plasma cells / memory cells (1)
How are memory cells important in immunity by vaccination (4)
Memory cells are stored from previous infection (1)
So when there is contact with the same antigen (1)
There is a more rapid response with more antibodies (1)
That destroy the pathogen before it causes harm (1)
