Topic 3- Infection and Response Flashcards
What are pathogens?
Pathogens are microorganisms that enter the body and cause disease.
What do pathogens (microorganisms) cause?
They cause communicable (infectious) diseases.
What are communicable diseases?
They are diseases that can easily spread.
What are bacteria?
Bacteria are very small (about 1/100th size of your body cell), which can reproduce rapidly inside your body.
What effect does bacteria have on your body?
They can make you feel ill by producing toxins (poisons) that damage your cells and tissues.
What are viruses?
Viruses are not cells. They’re tiny about 1/100th the size of a bacterium. They can reproduce rapidly inside your body.
What do viruses do inside your cell?
They live inside your cell and replicate themselves.
How do viruses replicate themselves?
They do this by using the cell’s machinery to produce many copies of themselves.
What happens after the virus replicate themselves within your cells?
The cell will usually then burst, releasing all the new viruses. This cell damage is what makes you feel ill.
What are protists like?
They’re all eukaryotes and most of them are single-celled. Some protists are parasites.
What are parasites?
Parasites live on or inside other organisms and can cause them damage.
How are protists transferred to an organism?
By a vector, which doesn’t get the disease itself.
Give an example of a vector that carries a protist.
An insect
What are fungi like?
Some fungi are single-celled. Other have a body which is made up of hyphae.
What are hyphae?
They are thread-like structures.
How do hyphae cause diseases?
These hyphae can grow and penetrate human skin and the surface of plants, causing diseases.
What can hyphae produce?
They can produce spores, which can be spread to other plants and animals.
Which organisms can be infected by pathogens?
- Plants
2. Animals
Give 3 ways in which pathogens are spread.
- Water
- Air
- Direct contact
How can a pathogen be spread through water?
Some pathogens can be picked up by drinking or bathing in dirty water.
How can a pathogen be spread through air?
Pathogens can be carried in the air and can then be breathed in.
How can a pathogen be spread through direct contact? (1)
Some pathogens can be picked up by touching contaminated surfaces, including the skin.
Give an example of how water can spread pathogens.
By cholera
How are airborne pathogens carried in the air?
They are carried in the air in droplets produced when you cough or sneeze.
Give an example of how air can spread pathogens.
The influenza virus that causes flu is spread through air.
How can pathogens be spread through direct contact? (2)
It’s most commonly spread by touching the same things as an infected person, e.g. shower floors and towels.
What are measles?
It is a viral disease. It is spread by droplets from an infected person’s sneeze or cough.
What do people with measles develop?
- Red skin rash
2. They’ll show signs of a fever (high temperature).
What are the 2 infections measles can cause?
- Pneumonia (lung infection)
2. Encephalitis (brain infection)
What do most people do to prevent themselves from having measles?
Most people are vaccinated against measles when they’re young.
What is HIV?
HIV is a virus spread by sexual contact, or by exchanging bodily fluids such as blood.
When do people exchange bodily fluids?
When people share needles when taking drugs.
What does HIV initially cause?
It causes flu-like symptoms for a few weeks.
How can HIV be controlled?
It can be controlled with antiretroviral drugs.
What do antiretroviral drugs do?
These drugs stop the virus replicating in the body.
What does HIV attack in the body?
The immune cells.
What happens if the body’s immune system is badly damaged?
It can’t cope with other infections or cancers.
What is the name of the stage, when your body can’t cope with other infections or cancers?
The virus is known as late stage HIV infection, or AIDS.
What is tobacco mosaic virus (TMV)?
It is a virus that affects many species of plants, e.g. tomatoes.
What does TMV cause?
It causes a mosaic pattern on the leaves of the plants- parts of the leaves become discoloured.
What does the discolouration of the leaves mean?
It means the plant can’t carry out photosynthesis as well, so the virus affects growth.
What is the rose black spot?
It is a fungus that causes purple or black spots to develop in the leaves of rose plants.
What does the rose black spot do to leaves?
It turns the leaves to leave and the leaves drop off.
What happens if the leaves turn yellow and drop off?
Less photosynthesis can happen, so the plant doesn’t grow very well.
How is the rose black spot spread?
It spreads through the environment in water or by the wind.
How do gardeners treat the rose black spot?
- They may use fungicides
2. Or they strip the plant of its affected leaves
How can you prevent the spread of the rose black spot?
By destroying the affected leaves.
What is malaria caused by?
By a protist
Where does the life cycle of malarial protists take place in?
Inside the mosquito
What are mosquitos?
They are vectors.
What do mosquitos do?
They pick up the malarial protist when they feed on an infected animal.
What happens when a mosquito feeds on another animal?
It infects it by inserting the protist into the animal’s blood vessels.
What does malaria cause?
It causes repeating episodes of fever. It can be fatal.
How can the spread of malaria be reduced?
By stopping the mosquitos from breeding.
How can people be protected by mosquitos?
By using:
- Insecticides
- Mosquito nets
Give 2 bacterial diseases.
- Salmonella
2. Gonorrhoea
What is salmonella?
Salmonella is a type of bacteria that causes food poisoning.
What are the symptoms of salmonella?
- Fever
- Stomach cramps
- Vomiting
- Diarrhoea
What are the symptoms of salmonella caused by?
Toxins that the bacteria produce.
How can you get salmonella food poisoning?
By eating food that’s been contaminated with Salmonella bacteria.
Give 2 example of how you can get salmonella food poisoning.
- Eating chicken that caught the disease whilst alive.
2. Eating food that has been contaminated by being prepared in unhygienic conditions.
What is gonorrhoea?
It is a sexually transmitted disease (STD).
How are STDs passed on?
By sexual contact, e.g. having unprotected sex.
What is gonorrhoea caused by?
It is caused by bacteria.
Give 2 symptoms of gonorrhoea.
- They will get pain when urinating
2. Thick yellow or green discharge from the vagina or the penis
How was gonorrhoea originally treated?
They were originally treated with an antibiotic called penicillin.
What is the problem with using penicillin against gonorrhoea now?
Strains of the bacteria have become resistant to it.
Give 2 ways in which you can prevent the spread of gonorrhoea?
- People can be treated with antibiotics
2. Barrier methods of contraception, such as condoms.
Give 4 ways in which you can prevent the spread of disease.
- Being hygienic
- Destroying vectors
- Isolating infected individuals
- Vaccination
How can being hygienic prevent the spread of disease?
By using simple hygiene measures can prevent the spread of disease.
Give 2 circumstances in which you need to wash your hands the spread of disease.
- Washing your hands thoroughly before preparing food
2. Or by washing your hands after you’ve sneezed, this can stop you infecting another person.
How can you prevent the spread of disease through organisms?
By getting rid of the organisms that spread disease.
How can you kill vectors?
- Using insecticides
2. Destroying their habitat so that they can no longer breed.
How can you prevent the spread of disease if someone already has it?
By isolating the person with the communicable disease.
How can vaccinating people or animals stop the spread of diseases?
The vaccination helps them not develop the infection and then pass it on to someone else.
How does skin stop pathogens from entering the body?
The skin acts as a barrier to pathogens. It also secreted antimicrobial substances which kill pathogens.
How does the nose stop pathogens from entering the body?
Hairs and mucus in your nose trap particles that could contain pathogens.
How does the trachea and bronchi stop pathogens from entering the body?
The trachea and bronchi secrete mucus to trap pathogens.
What is the trachea and bronchi lined with?
Cilia
What is the cilia?
These are hair-like structures, which waft the mucus up to the back of the throat where it can be swallowed.
How does the stomach stop pathogens from entering the body?
It produces hydrochloric acid. This kills pathogens that make it that far from the mouth.
What is the most important part of the immune system?
It is the white blood cells.
What 3 things do the white blood cells do when they encounter a pathogen?
- Consume them
- Produce antibodies
- Produce antitoxins
What is phagocytosis?
It is when the white blood cells can engulf foreign cells and digest them.
What unique molecules does invading pathogens have?
Antigens
What does the white blood cell do when it encounters a foreign antigen?
They will start to produce proteins called antibodies to lock onto the invading cells so that they can be found and destroyed by other white blood cells.
What is special about the antibodies produced?
The antibodies produced are specific to that type of antigen- they won’t lock on to any others.