Infection and Response Flashcards
what are the features of viruses and how do they infect
very small
move into cells and use the biochemistry of it to make copies of itself
leads to cells bursting and releasing all of the copies into the bloodstream
damage and destruction of the cells make the individual feel ill
what are the features of bacteria
small
multiply very quickly through binary fission
produce toxins that damage cells
what are the features of protists
some are parasitic, meaning they use humans and animals as their hosts (live on and inside, causing damage)
what are the features of fungi
can be either single called or have a body made of hyphae
can produce spores which can be spread to other organisms
how are communicable diseases spread
direct contact
water
air (droplets)
how can the spread of pathogens be limited
improving hygiene
reducing contact with infected individuals
removing vectors
vaccinations
why are viruses dangerous
they can enter all types of cells, and scientists are yet to develop a medicine to cure them
what are the symptoms of measles
fever and red skin rash, can lead to other problems such as pneumonia, encephalitis and blindness
how are measles spread
droplet infection
how are measles prevented
vaccinations for young children to reduce transmission
what are the symptoms of HIV
flu like symtoms, then the virus attacks the immune system and leads to aids
how is hiv spread
sexual contact or exchange of bodily fluids
how is hiv prevented
spread = condoms, not sharing needles, screening blood
development of aids= antiretroviral drugs
what is tobacco mosaic virus
a plant pathogen affecting many species of plants including tomatoes
what are the symptoms of tobacco mosaic virus
discolouration of leaves
affected part of leaf cannot photosynthesise resulting in reduction of the yield
how is tobacco mosaic virus spread
contact between diseased and healthy plants
insects as vectors
how is tobacco mosaic virus prevented
good field hygiene and pest control
growing TMW resistant strains
what is salmonella
bacteria that live in the gut of different animals, which are ingested when we eat meat
what are the symptoms of salmonella
fever, stomach cramps, vomiting,
diarrhoea
how is salmonella spread
bacteria found in raw meat and eggs, unhygienic conditions
how is salmonella prevented
poultry are vaccinated against salmonella
keep raw meat away from cooked food
avoid washing it
wash hands and surfaces when handling it
cook food thoroughly
what are the symptoms of gonorrhoea
thick yellow or green discharge from the vagina or penis
pain when urinating
how is gonorrhoea spread
sexually transmitted disease spread through unprotected sexual contact
how is gonorrhoea prevented
using contraception
antibiotics
what are the symptoms of rose black spot
purple or black spots on leaves of rose plants
reduces area of leaf available for photosynthesis
leaves turn yellow and drop early
how is rose black spot spread
spores of the fungus are spread in water (rain) or by wind
how is rose black spot prevented
using fungicides or stripping the plant of affected leaves
what is malaria
protist pathogens that enter red blood cells and damage them
what are the symptoms of malaria
fevers , shaking
how is malaria spread
vector is female anopheles mosquito where the protists reproduce sexually
when mosquito punches the skin to feed on blood the protists enter the human bloodstream via their saliva
how is malaria prevented
insecticide coated insect nets while sleeping
removing stagnant water to prevent vectors from breeding
taking antimalarial drugs to kill parasites that enter the blood
what is the non specific defence system
system that works to prevent pathogens from entering the body
what is the role of the skin in the defence system
acts as a physical barrier
produced antimicrobial secretions to kill pathogens
good microorganisms known as skin flora compete with the bad microorganisms for space and nutrients
what is the role of the nose in the defence system
hairs and mucus which prevents particles from entering your lungs
what is the role of the trachea and bronchi in the defence system
secrete mucus in order to trap pathogens
cilia beat to waft mucus upwards so it can be swallowed
what is the role of the stomach in the defence system
produces hydrochloride acid that kills any pathogens in your mucus, food or drink
what does the specific immune system do
acts to destroy any pathogens which pass through the non specific immune system to the body
what is a large part of the specific immune system
white blood cells
what three things can white blood cells do
phagocytosis
producing antibodies
producing antitoxins
how does phagocytosis protect you
destroys pathogens meaning they cannot make you feel ill
how does producing antibodies protect you
each pathogen has an antigen on their surface
once antibodies begin to bind to the pathogens, they clump together making it easier for WBCs to find them
if you become infected again the specific antibodies will be produced at a faster rate
the individual is said to be immune and will not feel symptoms of the illness
how does producing antitoxins protect you
neutralise the toxins released by the pathogen by binding to them
how do vaccinations work
contain a dead or weakened form of a pathogen
stimulates the white blood cells to produce antibodies complementary to the antigens on the pathogen
what are the advantages of vaccination
eradicated many diseases so far
epidemics can be prevented through herd immunity
what are the disadvantages of vaccination
not always effective in providing immunity
bad reactions can occur in response to vaccines
what are antibiotics
medicines that kill bacterial pathogens inside the body without damaging body cells
they cannot kill viruses as they use body cells to reproduce meaning any drugs that target them would affect body tissue too
what do painkillers do
only treat the symptoms of the disease rather than the cause
what is a concern of antibiotics
bacteria are becoming resistant to antibiotics
mutations can occur during reproduction resulting in certain bacteria no longer being killed by antibiotics
when these bacteria are exposed to antibiotics only the non resistance ones die
the resistant bacteria survive and reproduce meaning the population of resistant bacteria increases
how do we stop development if resistant strains of bacteria
stop overusing antibiotics
finishing courses of antibiotics to kill all of the bacteria
why do antibiotics not work when there is a mutation?
only the non resistant bacteria die
the resistant bacteria survive and reproduce to its population increases
what do drugs need to be tested for?
toxicity, efficacy and dose
how do drugs get tested?
preclinical testing and clinical trials
how can plants be used in drugs
the chemicals that plants use to kill pests and pathogens can be used to treat symptoms or human diseases
what is aspirin used as and where does it come from?
painkiller and from willow
how is digitalis used and where is it from
used to treat heart problems and originates from foxgloves
how was penicillin discovered
alexander fleming was growing bacteria on plates
he found penicillin mould with clear rings around indicating there was no longer bacteria there
he found that the mould was producing penicillin which killed bacteria
what does preclinical testing do
using cells , tissues and live animals
what does clinical testing do
using volunteers and patients
what is the process of drug testing
first tested on healthy volunteers with a low dose so there aren’t harmful side effects
drugs are tested on patients to find the most effective dose
patients are split into placebo or drug receivers to view the effect
results are peer reviewed to check for repeatability
what is a single blind trial
only the doctor knows whether the patient is receiving the drug
what is a double blind trial
neither the patient or doctor knows who is receiving the drug so there are no biases
what are monoclonal antibodies?
identical antibodies that have been produced from the same immune cell.
how are monoclonal antibodies produced
- scientists obtain mice lymphocytes
- they are combined with tumour cells to form a hybridoma
- the hybridoma produces clones of itself
- the antibodies are collected and purified
where are monoclonal antibodies used?
pregnancy tests
laboratories to measure hormone/chemical levels
research
treatment for disease
how are monoclonal antibodies used in pregnancy tests
hormone called HCG is in urine of pregnant women
- one section of the stick has mobile antibodies complementary to hcg. attatched to blue beads
- second section has stationary antibodies complementary to hcg hormone which are stuck down to stick
- woman urinates on first section and if hcg is present it binds to mobile antibodies to form hcg/ antibody complexes
how are monoclonal antibodies used in labs
- the monoclonal antibodies are modified so that they will bind to the molecule that you are looking for
- the antibodies are bound to a fluorescent dye
- if the antibodies bind to molecules in sample , the dye can be seen
how are monoclonal antibodies used for cancer treatment
-produce monoclonal antibodies that bind to tumour markers to stimulate immune system to attack the cell
- using m a to bind to receptor sites on the cell surface membrane of cancer cells. growth stimulating molecules can’t bind so cell can’t divide
-m a to transport toxic drugs , chemicals or radioactive substances as they can only bind to cancer cells
advantages of using monoclonal antibodies
- they bind to specific cells, meaning healthy cells are not affected
-they can be engineered to treat many different conditions
-we are able to produce mouse human hybrid cells to reduce the chance of triggering an immune response
disadvantages of monoclonal antibodies
- it is difficult to attach monoclonal antibodies to drugs
-they are expensive to develop
- can trigger an immune response in humans because they are made from mice lymphocytes
what kind of issues can plants have
viral, bacterial and fungal pathogens
what are the common signs of plant diseases
stunted growth
spots on leaves
areas of decay
abnormal growth
malformed stems or leaves
discolouration
pests on leaves
what does stunted growth in plants indicate
nitrate deficiency
what does spots on leaves in plants indicate
black spot fungus on roses
what does abnormal growths indicate for plants
crown galls caused by bacterial infection
what does malformed stems or leaves indicate in plants
aphid infestation
what does discolouration indicate in plants
magnesium deficiency or tobacco mosaic virus
how can you identify the disease a plant has
using a gardening manual or website
identifying the pathogen by observing the infected plant in a laboratory
using monoclonal antibodies in testing it to identify the pathogen
what are the three plant diseases
tobacco mosaic virus (viral disease)
black spot (fungal disease)
aphids
how does nitrate deficiency stunt growth
nitrates in soil convert sugars made in photosynthesis into proteins
these proteins are needed for growth
how does magnesium deficiency cause chlorosis in plants
magnesium is needed to make chlorophyll
this pigment is green and its vital in photosynthesis
if less is made parts of leaves appear yellow + green (chlorosis)
what are the physical plant defences
tough waxy cuticle stops entry into leaves
cellulose cell walls form a physical barrier into the cells
plants have layes of dead cells around stems. the dead cells fall off with the pathogens
what is the reason for physical defences in plants
to prevent the invasion of microorganisms
what is the reason for chemical defences in plants
to deter predators or kill bacteria
what are examples of chemical plant defences
poisons deter herbivores
antibacterial compounds kill bacteria
what are mechanical defences in plants
thorns and hairs
leaves droop or curl when touches
mimicry to trick animals
