Pathogens and disease Flashcards
What is a pathogen?
A micro-organism that causes disease
How is an infectious disease caused?
A micro-organism enters and attacks the body
What are the two main pathogens?
Bacteria and Viruses
`Which pathogen is single celled?
Bacteria
What is bacteria useful for?
Making yoghurt and cheese
How do pathogens cause disease? (3 marks)
Pathogens reproduce quickly.
Bacteria splits into two and produces toxins.
Viruses take over your cells but don’t produce toxins.
Who was the doctor that insisted medical students wash their hands before delivering babies?
Ignaz Semmelweis
What are the four ways that we can catch disease?
Droplet infection - When you cough, sneeze or talk pathogens are given out and taken in from your breating system.
Direct contact - Touch
Contaminated food and drink - Raw and uncooked food or dirty water
Through a break in your skin - Cuts, scratches, needle punctures
What are the 3 main defence mechanisms and what do they do?
Skin - Acts as a barrier to micro-organisms
Blood - Forms a clot which dries into a scab
Mucus - Covers the lining of your lungs and tubes and traps pathogens.
What cell protects you from disease?
White blood cells
What are the three ways your white blood cells protect you from disease?
- Ingest micro-organisms
- Produce antibodies, these target bacteria and viruses and destroy them
- Produces anti toxins , these cancel out toxins
Give two examples of painkillers?
Paracetamol and aspirin
What are antibiotics?
Drugs that work inside your body to kill the bacteria that causes disease
Antibiotics don’t work on diseases caused by viruses, why?
Pathogens reproduce in the cells of your body, it is difficult to create drugs that kill the viruses without damaging the cells and the tissues of the body.
Who discovered penicillin and when?
Alexander Fleming in 1928
When we are trying to grow micro-organisms in a lab, what do we keep the nutrients in?
Agar Jelly
What do we put all the agar jelly in?
A petri dish
What is the risk with growing micro-organisms?
A mutation could happen
What is a mutation?
A change in the DNA, which could then produce a new dangerous pathogen
What is agar jelly?
A culture medium
What is the max temperature at which you can grow micro-organisms in a school/college lab?
25 degrees
Some mutations happen by chance, they produce new strains of bacteria by ___________
Natural selection
Why is important not to use antibiotics too much?
To prevent more resistant strains of bacteria
Is MRSA a bacterium or a virus?
A bacterium
What is the name of the unique proteins on the surface of every cell?
Antigens
Antigens join with ___________ to destroy __________
Antigens join with antibodies to destroy pathogens
What is a vaccine usually made of?
A dead/weak version of the pathogen
Give an example of;
- One bacterial disease you can be immunised against
- One viral disease you can be immunised against
- Tetanus/diptheria
- MMR/Polio
Which one is single celled?
Bacteria or viruses?
Bacteria
What don’t antibiotics treat?
Viruses
What happens when you overuse antibiotics?
Resistant strains of bacteria develop due to natural selection and mutation
When growing and investigating bacteria, what are inoculating loops used for?
To transfer micro-organisms through a flame
Why does the lid of a petri-dish need to be secured with tape?
To prevent contamination of the culture by air
