Microorganisms, Defence Against Disease Flashcards
Spontaneous generation theory
The thought that the microorganism appeared spontaneously from non living materials
Disproving the spontaneous generation theory
Pasteur’s famous swan neck experiments disproved this theory as they showed that “spoilage” only happened if the nutrient broth was left exposed to the air
Swan neck experiment
He used nutrient broth that had been sterilised through the boiling in a flask. He covered the openings of some flasks, left some open and to other flasks he introduced a swan neck bend and left them uncovered.
Swan neck results
The results prove that spoilage only happens if the microbes can gain access to the broth. We now understand that the nutrients in the broth are needed to provide the energy and materials required for cell division of bacteria
Pasteurisation
This involves heating foods to temperatures (but NOT boiling) and then chilling rapidly.
This techniques kills most bacteria that would otherwise result in food spoiling or unusable
Virus’
>HIV(AIDS) > rubella >measles >mumps >colds and flu > polio
Bacteriums
> salmonella
gonorrhoea
tuberculosis
chlamydia
Fungus
> athletes foot
HIV
Spread
Exchange of body fluid during sex or infected blood
Control/prevention/treatment
Using a condom reduces risk of infection
Drug addicts no sharing needles
NO CURE
Rubella
Spread Air born ( droplet inflection) through coughing and sneezing
Control/prevention/treatment
Prevented by MMR vaccination
Measles
Spread Air born (droplet infection) through coughing or sneezing or by contact
Control/prevention/treatment
Prevented by MMR vaccination
Mumps
Spread Air born (droplets infection) through coughing and sneezing
Control/prevention/treatment
Prevented by MMR vaccination
Cold and flus
Spread Air born (droplet infection) through coughing and sneezing
Control/prevention/treatment
Flu vaccination for targeted groups
Polio
Spread
Usually spread through drinking water contaminated with faeces
Control/prevention/treatment
Polio vaccination currently eradicated polio in the uk
Salmonella
Spread
Food contamination
Control/prevention/treatment
Food cooked thoroughly and not mixing cooked and uncooked foods can control spread
Antibiotics
Gonorrhoea
Spread
Sexual contact
Control/prevention/treatment
Condom reduces risk of infection
Antibiotics
Tuberculosis
Spread Air born (water droplets) through coughing and sneezing
Control/prevention/treatment
BCG vaccination.
If contacted treated with drugs and antibiotics
Chlamydia
Spread
Sexual contact
Control/prevention/treatment
Condoms reduce risk of infection
Antibiotics
Athletes foot
Spread
Contact
Control/prevention/treatment
Avoid direct contact in area where spores are likely to be present
Flip flops in changing rooms and around pool
Non-specific defences to diseases
>lungs >eyes >hair >stomach >cuts >skin
Lungs (defence)
Cells produce mucus which traps dust and germs. Cilla moves the mucus upwards
Eyes (defence)
Tear glands make an antiseptic fluid which kills germs
Hair (defence)
Follicles- glands in the skin make an antiseptic oil
Stomach (defence)
Acid made by lining of the stomach kills germs
Cuts (defence)
When cut the blood forms a clot which develops a scab to prevent entry of bacteria
Skin (defence)
Dead outer layer of skin forms a barrier
Why does your blood clot?
If skin is broken at any point there is a chance that pathogens could enter
How does the blood clot?
When cut, platelets in bloodstream come into contact with the air. They rupture releasing chemicals that cause a protein fibrinogen to become insoluble protein fibrin.
This forms a mesh of fibres over the wound and cause more to rupture. They become sticky and become a platelet plug.
What does blood clotting prevent?
> blood loss
>pathogens entering the bloodstream
what is the immune sexy stem responsible for?
It deals with any pathogens that breach the physical barriers and will enter the body causing an infection
What deals with pathogens (foreign invaders)?
White blood cells
Phagocytes
White blood cells capable of detecting, ingesting and digesting foreign cells- known as PHAGOCYTES
they have loved uncles and can change shape
Phagocytosis (stages)
- Digestion
- Migration- the phagocytes changes shape and moves towards the bacteria
- Bacteria becomes engulfed
- Digestion- bacteria are digested by enzymes
The role of lymphocytes
> to recognise and label non-self (foreign) molecules
>produce antibodies following exposure to these foreign molecules
Type of lymphocytes
> T cells
>B cells
T cells
Attack those cells that have been invaded by bacteria
B cells
Release antibodies into the bloodstream
Antibodies
An antibody is a special type of protein molecule that labels materials as foreign- making it obvious to immune system
Antibodies and pathogens
> Antibodies can work by grouping pathogen together in clumps making the job more efficient
some can latch on to invading pathogens and cause them to burst
Antigens
Am antigen is a very small part of invading pathogens
Antigens and antibodies
There are million of antigens recognised by our bodies and each of these in turn has its own antibody
Each antigens have its own unique shape
T cells
Attack those cells that have been invaded by bacteria
B cells
Release antibodies into the bloodstream
Antibodies
An antibody is a special type of protein molecule that labels materials as foreign- making it obvious to immune system
Antibodies and pathogens
> Antibodies can work by grouping pathogen together in clumps making the job more efficient
some can latch on to invading pathogens and cause them to burst
Antigens
Am antigen is a very small part of invading pathogens
Antigens and antibodies
There are million of antigens recognised by our bodies and each of these in turn has its own antibody
Each antigens have its own unique shape
Immune response graph
The initial infection antibodies produced slowly (symptoms become apparent). Eventually antibodies levels are high enough to counter infections
Secondary infection activates the memory lymphocytes the response is much more rapid with huge amounts of antibodies produced ( no symptoms)
Active immunity
The type of immunity obtained when your own lymphocytes are stimulated to produce antibodies
Types of active immunity
> Natural active immunity
> artificial active immunity
Natural active immunity
A pathogen enters the body and is detected- your lymphocytes then make antibodies
Artificial active immunity
Vaccines contain a changed form of disease- an organism closely related to the pathogen that has minimal effects or attenuated pathogen or a toxoid.
This has the effect of activating lymphocytes to produce antibodies.
Toxoid
A non toxic toxin
Active immunity effects
Have long lasting effects- you should be protected for life
Passive immunity
When the immune system is not activated but your really still protected form disease
Nature passive(innate) immunity
Would be obtained in the first few weeks after birth
A mothers milk contains many preformed antibodies, these are taken into the body and used to protect against disease in the first months
Artificial passive immunity
When you would be injected with preformed antibody form another source
Types of passive immunity
> natural passive immunity
>artificial passive immunity
Passive immunity effects
It is not long lasting like active immunity
The main point with passive immunity is that your lymphocytes do not make the antibodies
Why is a poster vaccination needed?
Sometimes the initial vaccination does not raise that antibody levels high enough to provide protection
Vaccines and foreign travel
People from one country will not have been exposed to many pathogens found in other countries and will not have developed immunity to these disease
E.g. African continent
Antibiotics
Antibiotics are chemical compounds produced by soil fungi and bacteria
They are used to treat bacterial infections
When did Alexander Fleming discover the first antibiotic?
He accidentally discovered penicillin in 1928
How did Fleming discovered penicillin?
He isolated it from the mould penicillium not arum and found it prevented the growth of bacteria
1940 and penicillin
It was not available for commercial use until Florey and chain purified it in 1940
Mass production in 1940s
Collaborative nature of science
Fleming, Florey and chain won the Nobel prize in 1945 for this work
What is a fermenter?
It allows the production of penicillin on a commercial scale.
It is large vessel similar to those used to make insulin
Why are fermenters used?
The create the ideal growth conditions to ensure maximum yield.
What is down streaming?
The products will require down streaming - extraction, purification and packaging before they can be used
What is a superbug ?
It is a bacterium that has developed resistance to a range of antibiotics
Why have superbugs become resistant?
This is most likely die to some bacteria developing mutations providing them with protection against the antibiotic that would otherwise kill them
Overuse of antibiotics
Overuse is directly linked to the development of strains as C.difficile and MRSA
There is a fear that in the future we may not have suitable antibiotics to fight off infections- this could have drastic effects on the population
Deep cleans
Hospitals often carry out deep cleans to try and reduce the like hood of a superbug outbreak but good personal hygiene as well as isolation of patients who contact a super bug is also important
Multodisc
Is a disc with a umber of different antibiotics in it.
This allows us to see which antibiotics is best at dealing with a specific bacterium
Where is the multodisc used?
This technique is intern used in hospital labs to determine which antibiotics should be used to treat new infections
Multodisc
Is a disc with a umber of different antibiotics in it.
This allows us to see which antibiotics is best at dealing with a specific bacterium
Where is the multodisc used?
This technique is intern used in hospital labs to determine which antibiotics should be used to treat new infections
Multodisc
Is a disc with a umber of different antibiotics in it.
This allows us to see which antibiotics is best at dealing with a specific bacterium
Where is the multodisc used?
This technique is intern used in hospital labs to determine which antibiotics should be used to treat new infections
Multodisc
Is a disc with a umber of different antibiotics in it.
This allows us to see which antibiotics is best at dealing with a specific bacterium
Where is the multodisc used?
This technique is intern used in hospital labs to determine which antibiotics should be used to treat new infections
Multodisc
Is a disc with a umber of different antibiotics in it.
This allows us to see which antibiotics is best at dealing with a specific bacterium
Where is the multodisc used?
This technique is intern used in hospital labs to determine which antibiotics should be used to treat new infections
Multodisc
Is a disc with a umber of different antibiotics in it.
This allows us to see which antibiotics is best at dealing with a specific bacterium
Where is the multodisc used?
This technique is intern used in hospital labs to determine which antibiotics should be used to treat new infections
