B3 Flashcards
What are pathogens?
Microorganisms that enter the body and cause communicable disease.
What is bacteria?
Small cells that can reproduce very quickly in the body. They produce toxins that make you ill and damage your cells and tissue
What are viruses?
- Much smaller than bacteria
- Reproduce quickly in the body
- Live in cells and replicate
- Then they burst releasing new viruses
What are protists?
Eukaryotes (multicellular). Some are parasites which live in or inside other organisms.
How can pathogens be spread?
- water, by drinking dirty water
- air, carried by air and breathed in
- direct contact, touching contaminated surfaces
How is measles spread?
By droplets of liquid from sneezes and coughs
What are the symptoms of measles?
Red rash on the skin and fever
How is HIV spread?
Spread by sexual contact or exchanging of bodily fluids
How does tobacco mosaic virus affect plant growth?
Infects the chloroplasts, changes the leaves and changes their colour from green to yellow or white. This reduces the amount of sunlight being able to be absorbed for photosynthesis and therefore less of it occurring. Refusing the rate of plant growth
Give an example of a plant that TMV effects
Tomatoes
What does tmv cause in plants?
Cause the leaves to discolour in a mosaic pattern
Malaria is caused by what?
The protist - mosquito
The protist for malaria is inserted into what?
The blood vessel
What type of disease is gonorrhoea and salmonella?
Bacterial
What are the symptoms of salmonella?
Fever, stomach cramps, vomiting and diarrhoea
What causes salmonella?
Food contaminated with salmonella
How is gonorrhoea spread?
Passed on by sexual contact
How to prevent the spread of bacterial diseases?
- being hygienic, washing hands thoroughly
- destroying vectors, using insecticide or destroying their habitats
- isolating the infected
- vaccinating people
What barriers do the body have when defending itself from disease?
- the skin acts as a barrier to pathogens
- hairs and mucus in the nose trap particles
- the trachea and bronchi secrete mucus to trap pathogens.
- the stomach contains hydrochloric acid to kill pathogens that enter the body via the mouth
What is phagocytosis?
When white blood cells engulf pathogens and digest them
What do white blood cells produce?
- Antitoxins to neutralise the toxins
- antibodies. They lock onto the antigen on the outside of the pathogen the white blood cells can then destroy the pathogens
What is a vaccination?
And infection of a dead or weakened version of the pathogen
How do vaccinations work?
They carry antigens which cause your body to produce complimentary antibodies which will attack the pathogen, if you get infected again the white blood cells can produce antibodies quickly
What are pros of vaccines?
- helps to control communicable diseases
- epidemics can be prevented
Cons of vaccines
- don’t always work
- some people have a bad reaction (which is very rare)
What are the three main stages of drug testing?
Pre - clinical
1. Drugs are tested on human cells and tissues
2. Testing carried out on living animals
Clinical testing
3. Tested in healthy human volunteers in clinical trials, started with low dose then tested on people with the disease to determine dosage
What is a placebo?
A substance that looks like the drug but does not do anything
What is the placebo effect?
When the patient thinks the treatment will work even tho their treatment isn’t doing anything
What is a blind trial?
When the patient doesn’t know if they are getting the drug or placebo
What is a double- blind trial?
When both the doctor and the patient do not know whether they are getting the drug or the placebo
What plant / microorganism did aspirin come from?
Willow
What plant / organism did digitalis come from?
Foxglove
What plant / organism did penicillin come from?
Mould
If the pathogens enter the immune system tries to destroy the pathogens
Describe how the immune system defends the body against disease
- White blood cells detect foreign antigens
- phagocytosis engulfing the antigens
- Releases antibodies which attached to the antigen and destroy it
- Produce antitoxins which destroys toxins causing less damage to the cells and tissue
- also produces memory cells which means next time you’re infected there is a fast response
