Infection and Response Flashcards
How does bacteria make you feel ill?
By producing toxins that damage you cells and tissues
How do viruses make you feel ill?
Get inside your cells and use the cell to make copies of themselves which eventually burst the cell and this damage makes you ill
How do fungi cause disease?
They grow and penetrate the skin and then produce spores which can be spread
What are the main ways that pathogens are spread?
-dirty water e.g. cholera
-breathed in the air e.g. influenza
-direct contact e.g. athlete’s foot
What is measles?
-A virus spread by droplets from sneezing and coughing
-causes a red rash and fever
-can be serious and fatal e.g. lead to pnuemonia
-most are vaccinated young
What is HIV? How is its replication controlled?
-virus spread by sex or sharing needles
-starts with flu like symptoms
-replication controlled with antiretroviral drugs
-attacks immune cells
What is Tobacco Mosaic Virus (TMV)?
-virus in plants
-causes mosaic pattern on leaves, parts get discoloured
-hinders photosynthesis and growth
What is Rose black spot? How is it spread and treated?
-fungus in roses
-causes purple or black spots on leaves and then they go yellow and drop off
-hinders photosynthesis and growth
-spread by water and wind
-treated with fungicides and by removing affected leaves
What is Malaria? How can its spread be prevented?
-disease caused by protist
-spread by vectors (mosquitos)
-causes repeated fever episodes
-can be fatal
-spread can be reduced by stopping mosquitos from breeding
-can be prevented using insecticides and mosquito nets
What is salmonella?
-bacteria that causes food poisoning
-causes D and V, fever, stomach cramps
-spread by contaminated foods
What is gonorrhoea?
-STD cause by bacteria
-causes pain when urinating
-originally treated with anitibiotic penicillin but some strains have now become resistant
-prevented by using contraception
How can we reduce and prevent the spread of disease?
-being hygenic
-destroying vectors
-isolating infected people
-vaccination
What is the body’s line of defence against pathogens?
-skin -> barrier, secretes antimicrobial substances
-hairs and mucus in nose -> trap pathogens
-trachea and bronchi ->secret mucus to trap pathogens
-cilia -> waft mucus up into the throat to be swallowed
-stomach -> produces hydrochloric acid to kill pathogens
What is the first stage of the immune system’s attack?
White blood cells engulf the pathogens. This is called phagocytosis.
What is the second stage of the immune system’s attack?
White blood cells start to rapidly produce antibodies which attack onto the antigens of all the pathogens so they can be found and destroyed. Antitoxins are also produced to counteract the toxins from the bacteria.
What is the third stage of the immune system’s attack?
Killer cells destroy the pathogen and memory cells are produced to remember how to fight that pathogen should the body become infected again.
How do vaccines work?
Small amounts of dead or inactive pathogens are injected into the body, carrying antigens which cause the immune system to produce antibodies to combat them. This means that if live pathogens invade the future, the white blood cells already know how to deal with them.
What are the pros and cons of vaccinations?
-controls and prevents outbreaks of viruses, reduces the cases of previously common viruses
-don’t always work, can sometimes cause bad reactions and side effects
What are examples of drugs that reduce symptoms?
pain killers and cold medicines which relive pain and discomfort without actually tackling the pathogen
Why can’t viruses be treated with medicine?
Because they get inside body cells which means it’s difficult to kill them without killing the body cells too
What are examples of drugs that cure the problem?
Antibiotics like penicillin which kill or prevent the growth of the pathogen without affecting the body cells. Different antibiotics kill different bacteria.
What does it mean if bacteria mutate to become antibiotic resistant? How is this prevented?
That they won’t be killed by antibiotics and the strain will continue to reproduce and spread. This is prevented by not over-prescribing antibiotics and finishing the whole course.
What are some examples of drugs that come from plants?
-Aspirin -> developed from willow trees
-Digitalis -> developed from foxgloves
What is an example of a drug that was developed from microorganisms?
Penicillin was discovered when it was found that a particular area of a petri dish that had grown mould was free from bacteria as it was producing a substance that killed it
What is the first stage of drug testing?
The drugs are tested on human cells and tissues
What is the second stage of drug testing?
Tested on live animals to test efficacy and toxicity and find the best dosage
What is the third stage of drug testing?
Testing on human volunteers in a clinical trial.
-healthy volunteers -> test for side effects
-ill people -> find optimum dose
-split into two groups, one with placebo
What are monoclonal antibodies?
Antibodies produced from a single group of genetically identical B-cells that only target one specific type of pathogen
How are monoclonal antibodies made?
-Mouse injected with antigen
-the B-lymphocytes that the Mouse’s body produces are taken and fused with the tumour cell
-this makes a hybridoma
-it divides quickly to make lots of clones that produce the monoclonal antibodies
How are monoclonal antibodies used?
-pregnancy tests
-measure levels of chemicals like hormones in the blood
-treating diseases like cancer
What are the advanatges of monoclonal antibodies?
They can treat diseases like cancer with causing less side affects than other treatment because they target specific cells
What are the disadvantages of monoclonal antibodies?
They cause more side affects than originally expected like vomiting, fever and low blood pressure so they used as widely as people thought
What mineral ions do plants need and why?
-Nitrates -> to make protein for growth
-Magnesium ions -> to make chlorophyll for photosynthesis, preventing chlorosis
What are the signs of a plant having a disease?
-stunted growth
-abnormal growths
-spots on leaves
-malformations
-rot
-discolouration
What physical defences do plants have?
-waxy cuticle to act as a barrier
-cellulose cell walls
-layers of dead cells around stems (e.g.) tree bark)
What chemical defences do plants have?
-producing antibacterial chemicals
-producing poisons to stop themselves from being eaten
What mechanical defences do plants have?
-thorns and hairs to stop themselves from being eaten
-leaves droop or curl when touched to knock insects off of them
-Mimic other organisms to blend in
