Disease And Immune System Flashcards
Give examples of diseases caused by Bacteria
Tuberculosis (Mammals)
Meningitis (Humans)
Ring rot (potatoes)
Give examples of diseases caused by Viruses
HIV/AIDS (Humans)
Influenza (Mammals)
Tobacco mosaic virus ( Plants)
Give examples of diseases caused by fungi
Black sigatoka (Banana)
Ringworm (Cattle)
Athletes foot (Humans)
Give examples of diseases caused by Protoctista
Late blight (Potatoes, tomatoes)
Malaria (Mammals)
What is direct transmission, and give examples.
A disease is transmitted directly from on organism to another.
Droplet infection (Sneezing)
Sex
Touch of infected organism
What is Indirect transmission and give examples
When a disease is transmitted from one organism to another via an intermediate (air, water, food, vectors)
What can effect disease transmission?
Overcrowding - Increases transmission
Climate - malaria spreads in hot climates due to ideal mosquito breeding conditions.
Social Factors - Health education ( Washing hands) Good healthcare.
Name 6 humans defended against infection, and how they work.
Skin - Physical barrier
Mucous membranes - traps pathogen preventing it getting in lungs
Blood clotting - plug wounds to prevent pathogen entry
Inflammation: swelling isolates pathogens.
Wound repair: re Form a physical barrier.
Expulsive reflexes: expel foreign objects from airway (Sneezing)
Give examples of plant physical defenses.
Plants have a waxy cuticle ( physical barrier) and prevents water collecting on the leaf.
Surround by cell walls (physical barrier)
Plants produce Callose, which is deposited between walls and membranes so it’s harder for pathogen entry. And in plasmodesmata limiting spread of the virus between cells.
Name some chemical plant defenses:
Produce saponins - Destroy cell membrane of fungi or pathogens.
Produce phytoalexins - inhibit growth of fungi or other pathogens.
Other chemicals which are toxic to insects ( Reduce feeding, therefore chance of infection)
What are the 4 stages of the immune response?
1 - Phagocyte engulfs pathogens
2 - Phagocytes activate T lymphocytes
3 - T lymphocytes activate b lymphocytes, which undergo clonal expansion and selection.
4 - Plasma cells produce antibodies specific to an antigen
How does phagocytosis occour?
1: Phagocyte identifies a foreign antigen
2: Phagocyte engulfs pathogen forming a phagosome
3: Lysosome fuses with pathogen forming a phagolysosome, which breaks the pathogen down.
4: Phagocyte becomes an antigen presenting cell, waste products are expelled from the phagocyte.
How do phagocytes activate T lymphocytes?
1: T lymphocyte with CD4 receptor binds to APC with the complementary receptor to the antigen.
2: T lymphocyte activated and undergoes clonal expansion to produce clones of itself.
How do B lymphocytes divide into plasma cells?
1: Antibodies bind to complementary antigens forming an antigen - antibody complex.
2: Substances are released from T helper cells, B cells are activated and undergo clonal selection.
3: Activated then undergoes clonal clonal expansion into plasma cells.
What do plasma cells do?
They secrete loads of antibodies, which bind to pathogens.
What are the different types of T lymphocytes?
T helper cells: Release interleukins to activate b lymphocytes.
T killer cells: attach to and kill cells that are infected with a virus
T regulatory cells: supress the immune response from other white blood cells. (Stop immune cells attacking body cells)
What are opsonins?
Chemicals which bind to and tag foreign cells, making them recognizable for phagocytes.
What are agglutinins?
These are molecules which bind multiple pathogens together. Easier for phagocytosis..
What are antitoxins?
Bind to toxins and neutralize them so they can no longer harm body cells.
Why is the primary response slow?
There aren’t many B lymphocytes that can maker the antibody needed to bind to the antigen. Eventually body produce antibodies, and Memory cells.
Why is the secondary response fast?
Clonal selection happens faster, so memory T lymphocytes divide into correct T lymphocyte and B lymphocytes into plasma cells
What is active immunity?
Required exposure to antigen
Takes a while for protection to develop
Protection is long term
Memory cells are produced
What is passive immunity?
No exposure to antigen
Protection is immediate
Protection is short term
Memory cells aren’t produced
What is natural immunity?
Active - When you become immune after catching a disease.
Passive - A baby becomes immune due to antibodies from its mother in placenta and breast milk.
