Antibodies Flashcards
What type of proteins are antibodies
Globular glycoproteins called immunoglobulins
Describe the structure of antibodies
Antibodies have a quaternary structure, presented as a Y shape, with 2 ‘heavy’ (long) polypeptide chains bonded by disulfide bonds to 2 ‘light’ (short) polypeptide chains.
What two regions does each polypeptide chain have
a constant region and a variable reason
Do the constant regions vary
They do not vary within a class (isotope) of antibodies but do vary between the classes.
What does the constant region do
Determines the mechanism used to destroy the pathogen
What is the amino acid sequence in the variable regions of antibodies like for each antibody
each antibodies variable region is made up of a different amino acid sequence
What happens at the variable region in the antibody
where the antibody attaches to the antigen to form an antigen - antibody complex
What is at the end of the variable region
The antigen - binding site
how many amino acids is in each antigen-binding site
110-130 different amino acids
How does the antibody get its specificity for binding
The antigen - binding sites vary greatly
What is the epitope
part of the antigen that binds to antibody
What does the ‘hinge’ region allow the antibody to do
gives flexibility to the antibody which allows different angles when binding to antigens
is the ‘hinge’ region present in all classes of antibodies
No
What do antigens and their complimentary antibody have
Complementary molecular shapes
What happens if an antibody randomly collides with a foreign cell that possesses non-self antigens with a complementary shape
it binds with an antigen to form an antigen-antibody complex
How many antigen - binding sites do antibodies have
at least 2
What do multiple antigen - binding sites allow antibodies to do
They can bind to more than one bacterium or virus at once
What is agglutination
Groups of the same pathogens become clumped together due to multiple antigen - binding sites
What does the binding of antibodies to the antigens do
Either neutralises the pathogen or acts like a marker to attract phagocytes to engulf and destroy the pathogen
What can phagocytes do as a result of agglutination
Phagocytose many pathogens at the same time
What two types of cell do B - Lymphocytes form during an immune system response
Plasma cells and Memory cells
What do memory cells form
Immunological memory
How long do memory cells last
for many years and often a lifetime
What are the two types of immune response
Primary Immune response, Secondary Immune response
What happens if the same antigen is found in the body a second time
The memory cells recognise the antigen , divide and differentiate into plasma cells and more memory cells
How fast is the secondary immune response
The response is quick, meaning that the infection can be destroyed and removed before pathogen population increases too much
