Infection and response Flashcards
what is a pathogen
disease-causing organisms
what are examples of pathogens(4)
viruses
bacteria
fungi
protisits
how do bacteria affect the human body?
bacteria produce toxins which damage our cells
how do viruses affect the body?
viruses enter our body cells and reproduce inside them destroying our cells and making them burst
3 main viral diseases
HIV- human immunodeficiency virus
TMV- tobacco mosaic disease
Measles
3 bacterial diseases
gonorrhea
salmonella
rose black spot
what are communicable diseases?
diseases that can be spread
how can pathogens be spread?(4)
airborne
direct contact
droplet infection
water
How is gonorrhea spread
via sexual contact
Why is it difficult to develop drugs to kill viruses?
Viruses are usually found within body cells, so it is hard to kill the virus without damaging the body’s tissues.
What are the steps of phagocytosis?
1 First, the phagocyte tracks down a pathogen and binds to it.
2 The phagocyte’s membrane will then surround the pathogen and engulf it.
3 Finally, enzymes inside the phagocyte break down the pathogen in order to destroy it.
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What are bacteria?
Bacteria are tiny unicellular (single cell) organisms that are found almost everywhere.
Can a particular type of antibiotic kill all types of bacteria?
No. Each antibiotic is specific to an individual type of bacteria, or specific to a group of bacteria.
How does vaccinating a large proportion of the population help the people who didn’t get vaccinated?
Widespread vaccination can result in herd immunity, which help prevent outbreaks of disease.
This means the disease is very unlikely to spread from an infected person to someone who is not vaccinated, because almost everyone else is vaccinated.
What are the symptoms of TMV?
It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves which affects the growth of the plant due to lack of photosynthesis.
How does the skin act as a defence against pathogens?
1 It covers the body, physically preventing pathogens from entering.
2 It secretes oils and antimicrobial substances that kill pathogens.
Which organism did aspirin originate from?
Willow tree.
What does the drug ‘digitalis’ treat?
Heart failure
What does HIV stand for?
HIV stands for Human Immunodeficiency Virus.
This is because it affects humans, it weakens the immune system (immunodeficiency), and it is a virus.
What are the initial symptoms of HIV?
Flu like illness
Can an antibiotic kill viruses?
No they can only kill bacteria
Which body cells does HIV attack?
Immune cells - specifically, a type of white blood cell.
With reference to drug testing, what is a placebo?
A placebo is a substance or treatment that looks like the real treatment, but contains no active drug.
What is antibiotic resistance?
Occasionally, by random chance, bacteria evolve so that antibiotics no longer kill them. In these cases we say that the bacteria has developed ‘antibiotic resistance’.
What is a pathogen?
A disease causing microorganism
Which organism did penicillin originate from?
A type of fungus - specifically a mould known as Penicillium.
What do antibodies bind to?
They bind to antigens with a complementary
shape
What are the symptoms of the disease ‘rose black spot’?
Purple or black spots develop on the leaves, which then turn yellow and drop off early.
2 It also affects the growth of the plant as photosynthesis is reduced.
What are the symptoms of malaria?
Recurrent episodes of fever (feeling hot and cold). In some cases it can be fatal.
What type of organism causes gonorrhea?
Bacteria
How is gonorrhoea spread?
Via sexual contact
What is the treatment for HIV?
Antiretroviral drugs
What is a painkiller?
Painkillers are used to treat the symptoms of disease, but do not kill pathogens.
What type of drug is ‘aspirin’?
Painkiller
How can the spread ofmalaria be reduced?
1 Kill the mosquito (which are transmitting it) by using insecticides.
2 Destroy the mosquito breeding sites.
(3 Prevent getting bitten by mosquitoes by using insect repellents, or bed
What is phagocytosis (in one sentence)?
Phagocytosis is the process by which a phagocyte engulfs and destroys a pathogen (or a cell that contains a pathogen).
What are fungi?
Fungi are eukaryotic organisms that can be unicellular (e.g. yeast), or multicellular (e.g. mushrooms).
How does isolation (or quarantine) reduce the spread of pathogens
If an infected person is isolated, they can’t spread that disease to others because they don’t come into contact with other people.
What is an antibiotic?
Antibiotics are used to treat or prevent bacterial infections. They work by killing bacteria or preventing them from dividing.
Give 3 drawbacks of vaccinations.
1 They don’t always give full immunity to the disease.
2 They can cause mild symptoms such as fever or a sore arm.
3 They can, in very rare cases, cause severe reactions such as seizures.
How does hygiene reduce the spread of pathogens?
Washing things (e.g. our hands / food) kills the pathogens on them.
This stops the pathogens from spreading and infecting other people.
How does measles spread between people?
The measles virus is spread by inhaling virus-containing droplets from sneezes and coughs.
How is rose black spot spread?
It is spread in the environment by water or wind.
How does the stomach act as a defence against pathogens?
It produces stomach acid (hydrochloric acid), which creates a very low pH that destroys pathogens.
