Turning Points In Biology Flashcards
What is a vaccine?
A substance containing dead or inactive microbes used go immunise against disease.
How does a vaccine work?
A vaccine contains dead or inactive forms of a disease causing microbe. This means that the microbe cannot make you ill, but your body thinks that the harmful, active microbe has entered your body.
When a vaccine is inserted into the body, white blood cells make antibodies to fight against the dead or inactive microbe. Once white blood cells have made antibodies once, they remember how to do so, and if the real microbe enters your body, the antibodies will be quickly created and will destroy it before it causes disease.
In what way are people usually immunised?
Usually in the form of an injection, sometimes by drops into the mouth.
What is meant by an immunisation?
A method of inserting a vaccine into the body to prevent you from catching certain diseases.
Suggest why people may choose not to be immunised.
- They may have concerns about the safety of some vaccines.
- There may be possible side effects.
State to common side effects of immunisation.
- A temperature
- Sickness
- Swollen glands
- A small lump at the site of the injection
Severe side effects are very rare.
Name three ways that a medicinal drug can work.
Medicinal drugs work by preventing, treating or curing the symptoms of a disease.
State what antibiotics do.
Antibiotics kill bacteria that make you ill, but do not damage the cells in your body. They often damage bacteria cell walls or prevent them from forming.
What is an antibiotic?
A medicinal drug that kills bacteria.
How was penicillin discovered?
It was discovered accidentally by Alexander Fleming.
He grew bacteria on agar plates an in September 1928, he returned to work after a holiday to find mould (penicillium notatum) growing on one of the agar plates with bacteria growing that he had left stacked in his laboratory.
Fleming noticed that where mould was growing, bacteria were killed. He named the substance that killed the bacteria penicillin. He discovered that it killed many types of bacteria, such as those that caused meningitis and scarlet fever.
Why was Fleming carrying out research to try to discover chemicals that could kill bacteria?
Fleming worked in battlefield hospitals in WW1, where he saw many soldiers dying from bacteria infected wounds. After the war, he carried out research to try and discover chemicals that could be used to kill the bacteria.
What are antibodies?
Chemicals produced by the body that destroy pathogens. Different antibodies neutralise different pathogens.
How are antibodies produced?
When a pathogen enters the body, our white blood cells create antibodies to target the particular pathogens. When the pathogen enters for the first time, white blood cells take time to create enough antibodies to destroy it. During this time, the pathogen rapidly reproduces.
However, if the same pathogen enters our body again, our white blood cells remember how to create the antibodies, so they are produced more quickly. The pathogen is then destroyed before it makes you ill and you are immune to the disease. This is how vaccines work.
How is the right type of antibiotic to target a certain bacteria found?
To discover the right antibiotic to use, samples of bacteria can be spread over the surface of an agar plate.
Antibiotic discs, each soaked in different antibiotics, are then placed on the surface of the agar.
The agar plates are then placed in an incubator and left for the bacteria to grow.
The larger the inhibition zone, the more effective the antibiotic is on the type of bacteria being tested on. The antibiotic that created the largest inhibition zone should be used to treat the infection.i
How can bacteria become resistant?
When bacteria multiply, their DNA can be damaged or altered. This is known as mutation. Mutations usually result in the bacteria dying, but sometimes the mutation can be beneficial to the bacterium- the mutation may cause it to be resistant to an antibiotic.
If a person feels better so stops taking the antibiotic before the course is over, the resistant bacteria may rapidly reproduce, causing the whole bacteria population to be resistant to the antibiotic.
What are superbugs?
Bacteria that are resistant to most types of antibiotic.
What are mutations?
Changes to cells that can cause disease.
How can we prevent superbugs from developing?
- Washing our hands before eating/ preparing food/ after going to the toilet.
- use antiseptics to clean cuts and grazes. These are chemicals that kill microbes but do not damage your skin.
- clean toilets and kitchens with disinfectants
- use sterile medical equipment. Use only plasters and dressings that are sealed.
