12.6 Flashcards
What is an immune response? (2 marks)
The specific response to a pathogen, which involves the action of lymphocytes and the production of antibodies.
Antibodies are specialised glycoproteins called……. (1 mark)
Immunoglobulins
Are antibodies specific or non-specific? (1 mark)
Specific to one type of antigen.
Antibodies are complementary to their specific antigen, what model can be used to describe how they bind? (1 mark)
Lock and key model
How many polypeptide chains do disulfide bridges hold together? (1 mark)
4 polypeptide chains
The constant region is the same in all antibodies, what is its function? (2 marks)
Enables the antibody to attach to phagocytic cells and helps in phagocytosis.
The variable region has a different shape in each type of antibody, what causes this? (1 mark)
Its amino acid sequence.
Which part of the antibody is specific towards an antigen, how and why? (3 marks)
The variable region.
It is complementary to the shape of the antigen.
To ensure specificity towards an antigen.
What is the function of then hinge region in antibodies? (2 marks)
Allows flexibility–> Y shaped section can move further apart to attach to more than one antigen.
How do antibodies work? (3 marks)
Binds to antigen.
Antibody-antigen complex stimulates the digestion of bacteria by phagocytosis (like opsonin).
Most pathogens cannot affect body cells once they form an antibody-antigen complex.
What is agglutination? (2 marks)
One antibody binds to 2 pathogens, causing them to clump together.
This makes pathogens more easily engulfed by phagocytosis.
How do antibodies use neutralisation? (2 marks)
Antibodies can act as antitoxins, binding with toxins produced by pathogens, to make them harmless.
Name the two ways antibodies minimise pathogen’s effect on the body. (2 marks)
Agglutination
Neutralisation
What is an antigen? (1 mark)
A molecule that stimulates an immune response.
What is an antibody? (1 mark)
A protein molecule that can identify and neutralise antigens.
What are the specific immune system’s two main types of response to pathogens? (2 marks)
Cellular response
Humeral response
What is the specific immune system’s humoral response? (2 marks)
Antibodies
Targets pathogens in body fluids
What is the specific immune system’s cellular response? (2 marks)
Highly specialised cells
Target pathogens inside cells
Where are lymphocytes found? (1 mark)
Blood and lymph nodes
Do lymphocytes or phagocytes recognise antigens on pathogens? (1 mark)
lymphocytes
What are two main types of lymphocyte and where are they formed? (2 marks)
B lymphocytes- bone marrow
T lymphocytes- thymus
What do T helper cells produce? (1 mark)
Interleukins, a type of cytokine
What does interleukin do? (2 marks)
Stimulate B cell and antibody production.
Attracts other T cells and antibodies
How do T killer cells kill pathogens? (2 marks)
By producing a chemical called perforin, which makes holes in pathogen cell plasma membranes.
