disease and immunity Flashcards
what causes communicable disease
pathogens
what are pathogens
infective organisms
what are the 4 types of pathogens
bacteria, virus, fungi, Protoctista
are bacteria prokaryotes or eukaryotes
prokaryotes
bacteria being prokaryotes means that they have - cell structure to -
very different, the eukaryotic cells they infect
how do we classify bacteria
by their shape or cell wall
what shape is a bacilli bacteria
rod
what shape is a cocci bacteria
spherical
what shape is a vibrios bacteria
comma shaped
what shape is a spirilla bacteria
spiral
what shape is a spirochaetes bacteria
corkscrew
what do we use to see the cell wall of bacteria
gram staining
gram positive bacteria look
purple
gram negative bacteria look
red
why is gram staining useful
it can allow us to tell how the bacteria would react to antibiotics
are viruses living
no
viruses are bigger/smaller than bacteria
smaller
once viruses invade living cells, what do they do?
take over the biochemistry of the host cell to make more viruses
how are viruses successful pathogens
they reproduce rapidly and adapt to the environment of their host
what are bacteriophages
viruses that attack bacteria
all natural viruses are…
pathogens
Protoctista are prokaryotic/eukaryotic
eukaryotic
are all Protoctista pathogens
no
many protoctista move between hosts through
vectors
fungal diseases are typically worse in
plants
fungi are prokaryotic/eukaryotic
eukaryotic
many fungi are saprophytes meaning that
they feed off of dead and decaying matter
what is produced when fungi reproduce
spores
which pathogens directly damage their host cells
viruses, Protoctista, fungi
which pathogens produce damaging toxins
bacteria, fungi
how do viruses damage their host cells
they insert their DNA into the host cell’s DNA, then burst out of the cell and destroy it
how do Protoctista damage their host cells
they take over cells and break them open, using the cell contents for reproduction
how do fungi directly damage their host cells
they digest living cells and break them down for food
how do bacteria damage their host cells
they produce poisonous toxins, which either break down cell surface membranes, inactivate enzymes or interfere with genetic material to prevent mitosis
how do fungi indirectly damage their host cells
they produce toxins which affect the host cells
direct transmission of pathogens occurs as pathogens
move directly from one host to another
the 3 methods of direct transmission of pathogens are
- direct contact
- inoculation
- ingestion
what is direct contact (examples)
kissing, exchange of bodily fluids, skin to skin contact and microorganisms
what is inoculation (examples)
sex, animal bites, shared needles, puncture wounds
what is ingestion (examples)
contaminated food or drink, pathogens on the hands
what re the 3 modes of indirect pathogen transmission
- fomites
- inhalation
- vectors
what are fomites
where the pathogen travels through inanimate objects such as bedding
what is inhalation
small droplets of saliva or mucus containing pathogens may be breathed in
what are vectors
things which carry pathogens from host to host, such as insects or water
direct transmission of pathogens in plants is where
leaves or other plant parts touch
indirect transmission of pathogens in plants is
soil contamination or vectors
animal bacteria disease-
tuberculosis
what does tuberculosis do
destroys lung tissue and suppresses the immune system
how can we prevent tuberculosis
vaccines
how can we cure tuberculosis
antibiotics
plant bacteria disease-
ringrot
what does ringrot do
destroys leaves, tubers and fruit of potatoes, tomatoes and aubergines
animal virus disease-
HIV
what does HIV do
targets t helper cells and destroys the immune system
can we prevent or cure HIV
no
plant virus disease-
tobacco mosaic virus
what does tobacco mosaic virus do
damages leaves, flowers, fruits and stunts growth of plants
plant fungus disease-
black sigatoka
what plants get black sigatoka
bananas
what does black sigatoka do
destroys banana leaves and turns them black
plant protoctista disease-
late blight
what cause late blight
the protoctista oomycete
what does late blight do
destroys leaves, tubers and fruit
animal fungus disease-
athlete’s foot
what does athlete’s foot do
fungi grow on the moist, warm skin between toes
how can we cure athlete’s foot
anti-fungal creams
animal protoctista disease-
malaria
what causes malaria
a Protoctista called plasmodium
how is malaria spread
through the vector of mosquitoes
what does malaria do
Protoctista invade the liver, red blood cells and brain
how can we cure malaria
we can’t
how do we control malaria
by controlling mosquito populations
what are the 2 ways which plants recognise pathogens
chemicals are released when the cell wall is attacked, receptors in the cells respond to molecules from the pathogens
what happens when plant cells recognise pathogens
genes on the nucleus are switched on, sending alarm signals to unaffected cells and triggering responses
what is a plants physical defence
- callose is synthesised and deposited between cell walls and surface membranes in cells next to the infected ones, and in phloem sieve plates and plasmodesmata; the callose papillae act as barrier to prevent the spread of the infection.
- Lignin is added to the cell wall, making the barrier thicker
what are the plants chemical defences
- insect repellents
- insecticides
- antibitotics, antiseptics, lysosomes
- antifungal compounds
- anti-oomycetes
- general toxins
what are all the human non-specific primary defences
- skin
- mucous membranes
- lysozymes in tears and urine and stomach acid
- expulsive refluxes
- blood clotting and wound repair
- inflammatory response
how does our skin protect us
it is impermeable to most pathogens, and has a flora of healthy microorganisms to outcompete pathogens, and sebum to inhibit pathogen growth
how do mucous membranes act as a primary defence
they line body tracts, and secrete sticky mucus to trap microorganisms, contains phagocytes and lysozymes to destroy bacterial and fungal cell walls
how do lysozymes in tears and urine act as a primary defence
destroy bacterial and fungal cell walls
how do expulsive reflexes protect us
they expel pathogens
why is blood clotting used as a primary defence
it creates a scab so that pathogens can’t enter through wounds