B3 - Infection and Response Flashcards
(13 cards)
What are communicable diseases?
Diseases caused by pathogens
What is a pathogen and what are the 4?
A pathogen is a micro-organism that causes disease:
1 - Bacteria
2 - Viruses
3 - Fungi
4 - Protists
What do viruses do? Give 2 examples.
Viruses reproduce by inserting genes into cells which cause them to produce more copies.
Examples:
1 - Measles (rash - spread by droplets)
2 - HIV (an STD/STI that causes AIDS - compromised immune system)
What do bacteria do? Give 2 examples of bacterial infections.
Bacteria release toxins into your body that damage cells
Examples:
1 - Salmonella (undercooked food - food poisoning)
2 - Gonorrhea (STD - Causes yellow discharge)
What does fungi do?
Fungi damage cells
What are protists? Give an example.
Protists are single-celled organisms
Example:
- Malaria - Caused by a protists that infects red blood cells
Mosquitoes are the vector
Give 2 examples of plant diseases.
1 - Rose black spot (fungus) - Purple-black black spots appear on the leaves - causes leaves to fall off
2 - Tobacco mosaic virus (TMV) - discolours leaves by inhibiting chlorophyll production - means less photosynthesis - means stunted growth
Describe the body’s defences and immune response.
Skin - physical barrier
If pathogens enter nose and trachea - mucus in nose/trachea traps them - acids and enzymes in digestive system will destroy them too
If pathogens enter the bloodstream white blood cells combat:
1 - Lymphocytes - produce antitoxins and antibodies
- Antitoxins neutralise toxins made by pathogens
- Antibodies bind to the antigen of a pathogen (only if they fit - once the correct antibody is found, T cells store it in your lymph nodes, ready for next time [immunity] ). These antibodies stop viruses from infecting cells and cause them to clump together
2 - Phagocytes (another white blood cell) will then engulf and ingest them to destroy them
What is a vaccine?
A vaccine introduces a dead / inert version of a virus into your body so you gain immunity without becoming ill
What can and can’t antibiotics do?
They can:
Kill bacteria - the whole course has to be taken to kill ALL bacteria or more resistant bacteria will survive and multiply
They can’t:
Kill viruses - it’s difficult to make them target specific bacteria and not damage our cells or other ‘good’ bacteria
Where did many drugs used to derive from? Give 2 examples.
Many drugs used to derive from nature
1 - Aspirin (a painkiller) came from trees
2 - Penicillin (the first antibiotic) came from a mould
How are synthetic drugs made and what are they tested on?
Synthetic drugs cost a lot of money to develop
- They are put through trials to assess for EFFICACY (how well they work), TOXICITY and DOSE
They are tested on cell tissue, then animals, then humans
Describe the different types of synthetic drug trials.
Blind trial - Test group are given drug, control group are given placebo, without being made aware
Double blind trial - Doctors don’t know which is which to eliminate bias
