10 Communicable diseases Flashcards
What is a pathogen
a microorganism that causes disease
the 4 types of pathogens + examples
- Bacteria = tuberculosis (TB)
-virus = HIV/ AIDS , influenza
-Protoctista = malaria
-Fungi = ring worm, athletes foot
what is a vector
carries the pathogen from one host to another
what do bacteria do (4)
-infect host
-multiply rapidly
-causes damage to cells
-releasing waste products and toxins
what do viruses do (4)
-invade cells
-take over genetic machinery
-manufacture more viruses
-host cells burst
subcutaneous infection
-how the infection takes place
-how its transmitted
-an example
occurs by direct implantation of spores into the skin via a puncture wound
by contact with soil or plant material
porotrichosis
systematic infection
-how the infection takes place
-how its transmitted
-an example
occurs deep inside the body, often starting in the lungs and spreading to other parts of the body
usually through inhalation of spores
histoplasmosis
Cutaneous infection
-how the infection takes place
-how its transmitted
-an example
occurs when fungi break down the protein keratin in hair, skin , nails
by contact with an infected person or spores
tinea pedis (athletes foot)
what are the direct ways that a pathogen can be passed on (4)
-direct physical contact
-faecal oral
-droplet infection
-spores
what are the indirect ways/way that a pathogen can be passed on.
via a vector
what is ring rot in plants and its effect (3)
-Bacteria disease of potatoes, tomatoes and aubergines caused by the gram positive bacterium, clartbacter mithiganeusis. Can destroy up to 80% of the crop and there is no cure.
infects a field
field cannot be used for at least 2 years
What is tobacco mosaic virus (TMV) and its effect (5)
-infects tobacco plants + 150 other species such as tomatoes, peppers, cucumbers
-damages, leaves, flowers + fruit
-stunts growth
-reduces yield
-spreads via vectors
What is black sigatoka and its effect (5)
-banana disease
-caused by fungus
-attacks + destroys leaves
-penetrates + digests the cells, turning leaves black
-can cause a 50% reduction in yield
what is blight and its effect (3)
-potatoes + tomatoes
-spreads by wind as spores
-only grows (notice it) in warm + humid conditions
Physical defences against plant pathogens (5)
-cellulose cell walls
-lignin
-waxy cuticle
-bark
-stomatal closure
Human primary defences (7)
-lysome in tears (salty)
-bronchi, mucus, cilia
-gut acid
-rapid pH changes
-Low pH and commensals of vagina
-skin
-commensals
3 rapid expulsive reflexes
coughing
sneezing
vomiting
info card how does blood clot ( 8 steps)
-Damage to blood vessel exposes collagen
-platelets bind to exposed collagen; release clotting factor
-platelet plug is formed
-inactive thrombokinase is activated due to clotting factors
-active thrombokinase and Ca2+ turns prothrombin into active thrombin (an enzyme)
-Active thrombin catalyses the reaction of soluble fibrogen into fibrin (insoluble)
-insoluble fibrin fibres attach to platelets in platelet plug
-a clot is formed (red blood cells + platelets are trapped )
what cells recognise the pathogen
lymphocytes
what do the lymphocytes recognise
antigens
what’s an antigen
unique shaped molecules
what 4 types of cells can be detected by lymphocytes
-pathogens (bacteria, fungi virus)
-cells from other organisms of same species
-abnormal body cells
-toxins
how do many different types of lymphocytes do you have in your body and why
10 million
each one can recognise different shaped antigens
why do you not have lymphocytes complementary to your own cells?
When you are a foetus, since you are unlikely to be exposed to any cells that are not your own, any lymphocytes complementary to the antigens on your body their production will be stopped.
when you have some lymphocytes complementary to your own cells what’s it called
autoimmune disease
why is a new flu vaccine have to be created each year and what’s it called (7 steps)
-pathogen DNA mutates frequently
-if a mutation occurs in the gene coding for the antigen, then the shape of the antigen will change
-previous immunity is no longer effective
-memory cells in blood will have a memory of the old antigen shape
-lymphocytes no longer work for flu
-known as ANTIGEN VARIABILITY
-only will a new effective lymphocyte be created once a natural or artificial infection has occurred
in exam questions what would describe mean for a graph VS explain
Describe
-what the pattern is
-e.g. negative correlation
Explain (expand or elaborate)
-say WHY
-explain the biology of why there is a negative correlation
what do Tcells and Bcells do
+full names (what type of cell)
T cells = T lymphocytes
-respond to antigen
B cells = B lymphocytes
-produce antibodies
how are pathogens detected and the response given until antibodies are released (6 steps)
- pathogen detected by its unique antigens
-phagocyte engulfs the pathogen
-phagocyte displays the antigens on its surface to a T helper cell (T lymphocyte)
-T helper cell produce interleukins that activate the B cells (B lymphocytes)
-B cells divide by mitosis
-B cells differentiate into plasma cells which synthesize and release antibodies
what are interleukins
its a communication hormone that acts as a cell signalling molecule to activate B cells
what an antibody works
The antibodies has a Y shaped glycoproteins called immunoglobulins which bind to a specific antigen on the pathogen/ toxin
specific antibody for each antigen
how antigens actually work
Antigen- antibody complexes cause pathogens/ toxins to clump together, so a phagocyte can engulf a number of pathogens/ toxins at the same time
antibodies act as anti-toxins by binding to the toxins produced making them harmless.
