Infectious diseases, Immunity, Antibiotics and Painkillers Flashcards
Why do pathogens make us feel ill?
They release toxins, viruses also damage our cells
Where do viruses reproduce?
Inside cells
What is the name of the “marker” which indicates where a cell comes from?
An antigen
What do white blood cells produce when they detect a foreign antigen?
Specific antibodies
What do phagocytes do to pathogens?
They engulf and ingest them
What is in a vaccine?
Dead or inactive pathogen
What does MMR protect you against?
Measles, Mumps and Rubella
What do antibiotics destroy
Bacteria
Can a painkiller destroy bacteria?
No, it only treats symptoms
How does MRSA develop?
Natural Selection For a longer answer: Bacteria mutate or there is variation in bacteria. This leads to bacteria /resistant cells that survive an antibiotic. These antibiotic resistant cells go on to reproduce developing more antibiotic resistant cells.
Hand-gel dispensers are now placed at the entrance of most hospital wards. Explain why. (2 marks)
Kills / destroys bacteria / MRSA. Prevents / reduces transfer of bacteria.
Explain fully why antibiotics cannot be used to cure viral diseases. (2 marks)
Viruses live inside cells. Viruses are inaccessible to antibiotics
A recent study found that babies in 90 % of hospitals are infected with the MRSA bacterium. Explain how the MRSA bacterium has developed resistance to antibiotics. (2 marks)
A mutation occurs which is no longer recognised by antibiotics.
Explain how Semmelweiss’s results could be used to reduce the spread of MRSA in a modern hospital. (2 marks)
People wash hands after contact with patient so bacteria / pathogen / MRSA not transferred to other patient
Antibiotic-resistant strains of bacteria are causing problems in most hospitals. Explain, as fully as you can, why there has been a large increase in the number of antibiotic-resistant strains of bacteria. (4 marks)
- overuse of antibiotics - bacteria mutate - antibiotics kill non-resistant strains or idea of selection - reduced competition - resistant bacteria reproduce
Explain, as fully as you can, how the MMR vaccine protects children from these diseases (3 marks)
any three from: - vaccine is inactive / dead form of (pathogen) - stimulates antibody production - stimulates antitoxin production by white cells - antibodies kill (pathogen) - antitoxins neutralise poisons - antibodies quickly produced on reinfection
Explain why it is difficult to treat diseases caused by viruses. (2 marks)
any two from - live inside / infect body cells - difficult for drugs to enter (body) cells / drug would kill (body) cell - antibiotics ineffective against viruses - viruses mutate frequently
A person can be immunised against a disease by injecting them with an inactive form of a pathogen. Explain how this makes the person immune to the disease. (3 marks)
It stimulates antibody production by white cells. If later on, the live pathogen gets into your body, white blood cells recognise it and rapidly produce the antibodies. These antibodies destroy the pathogens before they can make you ill.
Which 3 ways do white blood cells help to protect us from pathogens?
engulf and ingest pathogens produce antibodies produce antitoxins
What is Aseptic technique and how do we culture bacteria safely? (6 marks)
To culture microorganisms, they need a culture medium called agar jelly. This contains the nutrients needed for growth. They should be incubated at 25∘C in school labs. They also need oxygen. Taping the plate at 4 points allows this to get in. To keep the culture pure you must pass metal loops through a flame, boil solutions and agar. Also prevent microorganisms getting in from the air.
What is the jelly called in the petri dish which we grow bacteria on?
Agar
What temperature do we keep agar plates in school at?
25 degrees C
How did Semmelweiss reduce deaths in Austria in the 1840’s?
Hand washing when moving between patients
During WW1 nearly 20% of US soldiers who caught pneumonia ( a bacterial infection) died as a result. During WW11 this figure dropped to less than 1%. Why?
We had penicillin to treat bacterial infections
What do we say viruses have done when they change their protein coat?
Mutated
What is a pandemic?
A global spread of a disease
What do White blood cells do?
Look at the diagram
Describe the graph and explain why it takes a week and a half to increase the antibodies after the first injection.
The line shows the antibody level increases a week and a half after the first vaccination, peaking at 4 weeks but the decreases and goes below the immunity level at 6 weeks when the booster is given. It then rises straight away. This is because the white blood cells know which antibody needs to be made straight away. The immunity goes up and this time stays abouve the immunity level.
What is a booster?
A follow up injection which you are given if your immunity drops
Who is this? Charles Darwin or Ignaz Semmelweiss?
Ignaz Semmelweiss
