B6 - Preventing And Treating Disease Flashcards
What is a vaccine?
A dead or weakened form of a pathogen
What are antibiotics?
Drugs that kill bacteria
Why cant antibiotics be used on viruses?
Viruses invade body cells so it is dificult to develop drugs that kill them without killing the body cells
What are painkillers?
Drugs that treat the symptoms of a disease but they dont kill the pathogen that caused it
What are the problems with antibiotics?
There are strains of bacteria that have become resistant to antibiotics
How does a vaccine work?
Once the weakened or dead pathogen has been destroyed a few memory cells remain.
They recognise the pathogen if it re-infects and make the immune responce much quicker and more effective (make more antibodies very quickly). This is called active immunity
What is herd immunity?
It is when lots of people are vaccinated and therefore a deadly disease will not spread as quickly
What are the 3 main stages in Drug Testing?
1) In preclinical testing, drugs are tested on human cells and tissues in the lab.
2) The next step in pre-clinical testing is to test the drug on live animals and this happens to check if the drug works and if it has the effects that you are looking for and to find out its toxicity and the correct dosage. The law in GB states that any new drug needs to be tested on 2 different live animals before it can be given to humans
3) If the drug passed the test on animals then its tested on human volunteers in a clinical trial. First it is tested on healthy volunteers and they start with a low dosage - to make sure there are no side effects when the body is working normally. Then its tested on people with the illness and the correct dosage is figured out. Then they give some people the drug and some people a drug that wont do anything ( the placebo test ). They do this so they know if it actually works or if the patient is just thinking that its working. Often the doctor also dosn’t know which one the drug is and which one the placebo is. This is so that the doctors monitoring the patients and analysisng the results aren’t subconsciously influenced by their knowledge. After this the drug is peer reviewed to prevent any false claims
What are antibodies produced by?
Antibodies are produced by B-lymphocites ( a type of white blood cell )
What are monoclonal antibodies? And how are they produced ?
Monoclonal antibodies are identical antibodies
Monoclonal antibodies are produced from lots of clones of a single white blood cell. This means all the antibodies are identical and will only target one specific protein antigen.
How do you make a monoclonal antibody?
A mouse is injected with the chosen antigen and then the B-lymphocytes are taken from the mouse. Then you get some fast dividing tumour cells and fuse them with the B-lymphocytes because B-lymphocytes dont divide easily. This makes a hybridoma and this hybridoma divides quickly to produce lots of monoclonal anitbodies
How are monoclonal antibodies used in pregnancy tests?
In the bit where you pee on there are some antibodies that bind to a hormone that is released when girls are pregnant, with blue beads attached to it. There are also some more antibodies stuck down further down the stick which bind to the hormone
If your pregnant and pee on the stick the hormones bind to the antibodies on the blue beads and the urine moves up the stick carrying the hormone and the beads and then the beads and hormones bind to the antibodies making it turn blue
If your not pregnant and you wee on the stick, the urine still moves up the stick, carrying the blue beads. But there’s nothing to stick the blue beads onto the test strip, so it doesn’t turn blue
What are the problems with monoclonal antibodies?
They cause lots of side effects such as fever, vomiting, low blood pressure
How can monoclonal antibodies be used to treat disease?
Monoclonal antibodies can be used to treat disease by binding to specific cells in the body.
Cancer cells have antigens on their cell membranes that aren’t found on normal body cells. They’re called tumour markers.
In the lab, you can make monoclonal antibodies that will bind to these tumour markers.
An anti-cancer drug can be attached to these monoclonal antibodies. This might be a radioactive substance, a toxic drug or a chemical which stops cancer cells growing and dividing.
The antibodies are given to the patient through a drip.
The antibodies target specific cells (the cancer cells) because they only bind to the tumour markers.
The drug kills the cancer cells but doesn’t kill any normal body cells near the tumour.
How can you use monoclonal antibodies to find specific substances?
1) First, monoclonal antibodies are made that will bind to the specific molecules you’re looking for.
2) The antibodies are then bound to a fluorescent die.
3) If the molecules are present in the sample you’re analysing, the monoclonal antibodies will attach to them, and they can be detected using the dye.
