Disease Flashcards
Describe tuberculosis
- Bacteria
- Transmitted via airborne droplets and contaminated food and drink
Name the 4 plant diseases and the type of pathogen that causes them
- Bacteria - ring rot (potatoes, tomatoes)
- Virus - tobacco mosaic virus (plants)
- Fungus - black sigatoka (bananas)
- Protoctista - potato/tomato late blight
What is callose and how does it contribute to plant defence?
A polysaccaride deposited between the cell wall and plasma membrane to make it harder for pathogens to enter cells
What chemicals do plant produce to defend themselves against pathogens?
- Insect repellents and insecticides - prevent insects from transmitting pathogens
- Antibacterial substances - to kill bacteria or inhibit their growth
- Toxins
How does the skin act as a chemical barrier?
It produces sebum, which is an antimicrobial substance that lowers pH
Briefly describe the process of blood clotting
Platelets release substance that, via a cascasde of events, result in the formation of fibrin which itself forms a network, trapping platelets and forming a clot
How do damaged tissues trigger inflammation?
They release chemicals that dilate blood vessels and increase permeability of their walls
What is the role of cytokines?
- Act as cell signalling molecules to trigger the movement of other phagocytes to sites of infection
- They can also stimulate an increase in body temperature
How do specific defence mechanisms differ from non-specific?
- Specific are slower
- But provide a unique response for each type of pathogen and provide long-term immunity
What is the function of T helper cells?
- Bind to APC’s and produce interleukins to stimulate B cells or phagoctyes
- Also form memory cells and T killer cells
What is the function of T regulator cells?
Suppress the immune system after pathogens have been destroyed
What are the different functions of cloned T cells?
- Develop into memory cells
- Develop into T killer cells
- Stimulate phagocytosis
- Stimulate division of T cells
What is clonal selection and clonal expansion?
- Clonal selection - the process of selecting B cells with the correct antibody for cloning
- Clonal expansion - the division of specific to produce genetically identical clones
What happens during the primary and secondary immune response?
- Primary - the concentration of antibodies increases slowly as B cells divide into plasma cells, which produce antibodies, and some divide into memory cells
- Secondary - the concentration of antibodies increases quickly as memory cells recognise the pathogens antigens and divide into plasma cells
What are the functions of T and B memory cells?
- T memory - divide to form many T killer cells
- B memory - divide into plasma cells that can produce antibodies specific to a pathogens antigens
How many polypeptide chains are antibodies made up of?
- Four polypeptide chains
- Two heavy and two light chains which are held together by disulphide bridges
What are the constant, variable and hinge regions on antibodies?
- Constant - same for all antibodies and bind to receptors on cells
- Variable - different for each antibody and bind to specific antigens
- Hinge - allows the antibody to be flexible and bind to multiple antigens at once
What is the role of antibodies in agglutination of pathogens?
They cause pathogens to clump together for easier phagocytosis
Describe active immunity, and give an example of natural active immunity
- Active immunity develops when the immune system produces its own antibodies after exposure to a pathogen’s antigens
- Natural active when antibodies are produced after infection by a pathogen
Describe passive immunity, and give an example of natural and artificial passive immunity
- Develops when an individual is given antibodies made by a different organism
- Natural passive when babies receive antibodies from their mothers through the placenta and breast milk
- Artificial passive when antibodies or toxins produced by one organism are injected into another organism
What is an example of an autoimmune disease?
Arthritis
What are some examples of substances vaccines may contain?
- Dead or inactivated pathogens
- Harmless toxins
- Isolated antigens
- Genetically engineered antigens
What are antibiotics?
- Drugs that kill or inhibit the growth of bacteria
- They target bacterial enzymes and ribosomes used in metabolic reactions, which are different from human enzymes and ribosomes
What are personalised medicines?
Medicines tailored to an individual’s DNA
