1.1 (P2) Defence Against Disease Flashcards
What is a pathogen
Microorganisms that cause infectious diseases
What is a virus
A DEAD pathogen
It cannot survive long unless inside a host cell
How do viruses attack you
They take over the nucleus in your cells and make copies of themselves then burst out and infect other cells
They reproduce rapidly and damage the cells
What is a bacteria
An ALIVE pathogen
How do bacteria attack you
They release toxins that make you feel ill
Name three general defences
Natural barriers
Non-specific white blood cells
Specific white blood cells
Name 2 Non-Specific white blood cells
Macrophages
Helper cells
Name natural barriers you body has
Saliva Mucus Ciliated epithelial cells Ear wax Skin Tears Eyelashes
Name the specific white blood cells
B-cells
T-cells
Phagocytes
What do phagocytes do
The engulf pathogens and hold up to 10,000 before dying
Where are B-cells and T-cells found
In the lymph glands
What do B-cells target?
A virus
What do T-cells target?
Bacteria
What do B-cells do?
They produce antibodies
The tiny proteins are sent to the infection via the blood stream
They attach themselves to the
What do T-cells do?
They multiply and go out if the gland to the infection themselves
They release antitoxins which only targets the infected cell
What can happen to T-cells?
They remain in the body in small quantities
They are called memory cells
What are memory cells vital for?
Immunity
Who is Ignaz Semmelweis?
A Hungarian physician
He found the link between microbes and infection
He saw doctors didn’t wash their hands between an autopsy and delivering a baby
He told them to wash their hands to prevent the spread of pathogens
What do painkillers do?
They relive the pain and symptoms
They don’t kill the pathogen
What are antibiotics?
They cure bacterial infections
They are natural - you can’t make them
Do antibiotics work on viruses? Why?
No
They reproduce inside host cells which makes it hard to target without killing the other cells also
What is the first antibiotic?
Who discovered it?
Penicillin
Alexander Flemming
What is the term for a change in DNA causing variation?
Mutation
What causes mutation?
Overuse
Inappropriate use
How does antibiotic resistance occur?
Natural selection
How does a resistant strain form?
Antibiotics kill individual pathogens of the non-resistant strain
However, some mutate and survive and reproduce
The population of the resistant strain increases
Name a resistant strain of bacteria
MRSA
What aren’t antibiotics used for and why?
Mild throat infections
So the rate of resistant strains slows down
What is a vaccine?
A small dead version of the virus
What vaccine is given to children?
MMR
What describes the act of making sure there is no contamination
Sterilisation
How can we work safely with microbes?
Sterilise
petri dishes, culture media and inoculating loops
Keep the lid on the petri dish sealed with adhesive tape to prevent microorganisms contaminating the culture
What temperature does bacteria grow best at?
37 degrees
What temperature and why do schools use to incubate cultures of bacteria?
25 degrees
The bacteria doesn’t grow efficiently and isn’t infectious or harmful to humans
What temperature does industrial use have?
Why?
100 or high temperatures
For rapid growth
How does a vaccination prevent infection?
A dead virus is injected in a small quantity
Your body reacts by creating antibodies to destroy the harmless virus
Next time your body will remember how to make the antibodies much quicker getting rid of it quicker
