Topic 2 C Flashcards
(37 cards)
What is an antigen?
Molecules that can generate the immune response found on the surface of cells
What are antigens called that aren’t usually found in the body?
Foreign antigens
What are pathogens?
Organisms that cause disease. Have antigens on the surface which triggers an immune response
What are toxins?
Poisons produced by bacteria
What occurs during phagocytosis?
A phagocyte recognises foreign antigen, the cytoplasms moves around the pathogen engulfing it containing it in a phagocytic vacuole, lysosomes fuse with vacuole and breaks down pathogen, phagocyte presents the antigens on its surface becoming an antigen presenting cell
What do T-cells do?
Has receptor proteins that bind to complementary antigens, activating the T-cell
What are the two types of T-cells?
helper T-cells and cytotoxic T-cells
How do helper T-cells respond to antigens?
Release chemical signals that activate phagocytes and cytotoxic T-cells
What do cytotoxic T-cells do once activated?
Kill abnormal and foreign cells and activate B-cells to secrete antibodies
What do B-cells do?
Covered in antibodies that bind to the antigen forming an antigen-antibody complex which activates the cell along with substances released by T-cells (clonal selection. They then divide into plasma cells
What do plasma cells do?
Secrete antibodies that are specific to the antigen (monoclonal antibodies)
How many binding sites do antibodies have?
Two
What does it mean that two pathogens can bind to the antibody?
They can become clumped together called agglutination
What happens once the pathogen is bound to the antibody?
Phagocytes attach to antibodies and phagocytose many pathogens at once
What is the structure of a antibody?
A heavy (long) chain and light (short) chain, variable regions at the end of chains that create the a binding site, disulfide bridges between heavy chains, hinge region, constant region
What is the difference between the humoral and cellular response?
Cellular includes T-cells and other cells they interact with while humoral includes B-cells, clonal selection and production of monoclonal antibodies
What is the primary response?
When the antigen enters the body for the first time, slow, show symptoms of disease, memory cells produced by B-cells and T-cells
What is the secondary response?
The pathogen re enters the body, faster, memory cells gets rid of pathogen before symptoms show
What is active immunity?
Immune system creates it’s own antibodies
Natural- become immune after catching a disease
Artificial- become immune after you’ve been given a vaccine with a harmless dose of the antigen
What is passive immunity?
Given antibodies made by a different organism
Natural- baby becomes immune from antibodies passed by mother
Artificial- Become immune after being injected by antibodies from someone else
When are antibodies and memory cells produced?
During active immunity
When is long term protection given?
During active immunity
What is herd immunity?
When vaccines protect the individual that have them and also the individuals who don’t
What are the ethical issues surrounding vaccines?
tested on animals, testing on humans can be risky, some don’t want to take but are still protected which may be seen as unfair
