B3-Infection and Response

• What are pathogens?


  microorganisms that enter the body and cause disease
• What do pathogens cause?

  communicable diseases
• What are communicable diseases?

  Diseases that can be easily spread from person to person or between animals and people.
• What can be infected by pathogens?


  both plants and animals
• What is bacteria?


  Very small cells which can reproduce rapidly inside your body
• What do bacteria do?

  They make you feel ill by producing toxins, that damage your skin and tissues.
• What are viruses?


  NOT cells and much smaller than bacterium
• What do viruses do?

  -Like bacteria, they reproduce rapidly inside your body.

  -They live inside your cells and replicate themselves using the cells 'machinery' to produce many copies of themselves.

  -The cell will then usually burst releasing all the new viruses.

  -This cell damage makes you feel ill
• What are protists?


  single celled eukaryotes
• What are some kinds of protists?

  -Parasites-they live on or inside other organisms and can cause them damage.

  -They are often transferred to the organism by a vector, which does not get the disease itself.
• What is fungi?


  Some single celled and other have body which is made up of hyphae.

  These can grow and penetrate human skin and the surface f plants, causing diseases.

  -The hyphae can produce spores, which can be spread to the plants and animals.
• How can pathogens be spread?

  1) Water - drinking/bathing in dirty water e.g. cholera

  2) Air - breathing it in or the spreading of droplets from coughs or sneezes e.g. the flu

  3) Direct contact - touching contaminated surfaces e.g. athlete's foot
• What are the three viral diseases?

  -Measles

  -HIV

  -Tobacco mosaic virus (TMV)
• What is measles ,how it is contracted and describe the symptoms and treatment?

  -Measles is a viral disease

  -It is spread by droplets from an infected persons sneeze or cough

  -People with measles develop a red skin rash and they will show signs of a fever (a high temperature)

  -Measles can be very serious or even fatal, if there are complications.e.g Measles can lead to pneumonia or inflammation of the brain.

  -Most people are vaccinated against measles when they are young.
• What is HIV,how it is contracted and describe the symptoms and treatment?

  -HIV is a virus spread my sexual contact, or by exchanging bodily fluids such as blood.This can happen when people share needles when taking drugs.

  -HIV initially causes flu like symptoms for a few weeks.Usually the person then does not experience any symptoms of HIV for several years.

  -HIV can be controlled by antiretroviral drugs, these stop the virus from replicating in your body

  The virus attacks the immune cells.

  If the body's immune system is badly damaged, it cannot cope with other infections or cancers.ATS-the virus is known as late stage HIV or AIDS.
• What is Tobacco mosaic virus ,how it is contracted and describe the symptoms and treatment?

  -Tobacco mosaic virus is a virus that affects many species of plants

  -It causes a mosaic pattern on the leaves of the plants-parts of the leaves become discoloured.

  -The discolouration means the plant cannot carry out photosynthesis as wells the virus affects growth.
• What is the example of a fungal disease?


  Rose black spot
• What is Rose black spot ,how it is contracted and describe the symptoms and treatment?

  -A fungus that causes purple or black spots to develop on the leaves of rose plants.The leaves can then turn yellow and drop off.

  -This means there is less photosynthesis happening, so the plant does not grow that well.

  -It spreads through he environment in water or by wind

  -Gardeners can treat the disease with fungicides and by stripping the plant of its affected leaves.These leaves then need to be destroyed so that the fungus cannot spread to other rose plants.
• What is the example of a disease caused by protists?

  Malaria
• What is malaria ,how it is contracted and describe the symptoms and treatment?

  -Malaria is caused by protists

  -Parts of the malarial protist's life cycle takes place inside the mosquito.The mosquitos are vectors-they pick up the malarial protist, when they feed on an infected animal.

  -Every time the mosquito feeds on another animality infects it by inserting the protist into the animals blood vessel.

  -Malarias causes repeated episodes of fever.It can be fatal.

  -The speed of malaria can be reduced by stopping the mosquitos from breeding.People can be protected from mosquitos using insecticides and mosquito nets.
• What are examples of bacterial diseases?

  -Salmonella

  -Gonorrhoea
• What is salmonella,how it is contracted and describe the symptoms and treatment?

  -Salmonella is a type of of bacteria that causes food poisoning.

  -Infected people can suffer from fever, stomach cramps, vomiting and diarrhoea

  -These symptoms are caused by toxins that the bacteria produce

  -You can get salmonella food poisoning by eating food that has been contaminated with salmonella bacteria e.g eating chicken that caught the disease whilst alive or eating food that can been prepared in unhygienic conditions.

  -In the UK most poultry is given a vaccination against salmonella-to control the spread of disease.
• What is gonorrhoea,how it is contracted and describe the symptoms and treatment?

  -Gonorrhoea is a sexually transmitted disease

  -STDS are passed on by sexual contact-having unprotected sex

  -Gonorrhoea is caused by bacteria.

  -A person with gonorrhoea will get pain when they urinate. Another symptom is a thick yellow or green discharge from the vagina or the penis.

  -Gonorrhoea was originally traded with an antibiotic called penicillin, but this has become trickier now because strains of the bacteria have become resistant to it

  -To prevent the spread, people can be treated with antibiotics and should use barrier methods of contraception such as condoms.
• How can the speed of disease be reduced or prevented?

  -Being hygienic-using simple hygiene measures can prevent the spread of disease. e.g washing your hands thoroughly before preparing food or after you have sneezed to avoid infecting another person.

  -Destroying vectors-By getting rid of the organisms that spread disease, you can prevent the disease form being passed on.Vectors are insects that can be killed using insecticides or by destroying their habitats so that they can no longer breed.

  -Isolating infected individuals-isolating someone who has a communicable disease, prevents them from passing it on to anyone else

  -Vaccination-vaccinating people and animals against communicable diseases means that they are less likely to develop the infection and then pass it on to someone else.
• Which features does the human body have to protect it from pathogens?

  -The skin cuts as a barrier to pathogens.It also secrete antimicrobial substances that kill pathogens.

  -Hairs and mucus in your nose, trap particles that could contain pathogens

  -The trachea and bronchi secrete mucus to trap pathogens.

  -The trachea and bronchi are lined with cilia.These are hair like structures which waft the mucus up to the back of the throat where it can be swallowed.

  -The stomach produced hydrochloric acid-this kills pathogens that make it that far from the mouth.
• What happens when pathogens make it into your body?

  -Your immune system kicks in to destroy them

  -The most important part is the white blood cells-they travel around in your blood and crawl into every part of you, controlling patrolling microbes.
• What are the white blood cells three lines of attack?

  -Consuming them-

  -Producing antibodies

  -Producing antitoxins
• How does a white blood cell consume a pathogen?

  -White blood cells can engulf foreign cells and digest them

  -This is called phagocytosis.
• How does the white blood cell produce antibodies?

  -Every invading pathogen has unique molecules on its surface

  -When white blood cells come across a firing antigen, they will start to produce proteins called antibodies to lock onto the invading cells so they can be found and destroyed by other white blood cells.

  -Antibodies are then produced rapidly and carried around the body to find all similar bacteria or virus.

  -If the person is infected with he same pathogen again the white blood cells will rapidly produce the antibodies to kill it-the person is naturally immune to that pathogen and won't get ill.
• How do white blood cells produce antitoxins


  These counteract toxins produced by the invading bacteria
• What happens when you are infected with a new pathogen?

  Takes your white blood cells a few days to learn how to deal with it-by the you can be pretty ill.
• What are vaccinations?


  -Involve injecting small amount of dead or inactive pathogen.

  -These carry antigens which cause your body to produce antibodies to attack them-even though the pathogen is harmless (since dead or inactive)
• What happens after the live pathogens appear after that?

  The white blood cells can rapidly mass-produce antibodies to kill off the pathogens.
• What are the pros of vaccination?

  -They have helped to control communicable diseases that were once common

  -Epidemics can be prevented if a large percentage of the population is vaccinated
• What are the cons of vaccination?

  -They don't always work-sometime they do not give you immunity

  -You could have a bad reaction to a vaccine-even though they are rare.
• What are painkillers?


  -Drugs that relieve the pain and help reduce the symptoms of a disease

  -DON'T ACTUALLY TACKLE THE CAUSE OF THE DISEASE OR KILL THE PATHOGEN.
• What are antibiotics?


  Drugs that actually kill or prevent the growth of the bacteria, without killing your own body cells.
• Why is it important to be treated with the right antibiotic?

  Different antibiotics kill different types of bacteria
• Where do antibiotics never work?

  -Don't destroy viruses

  -Viruses reproduce using your body cells which makes it difficult to develop drugs that destroy just the virus without killing the body cells.
• How has antibiotics helped?

  Greatly reduced the number of deaths from communicable diseases caused by bacteria.