B3 Flashcards
(30 cards)
What is a pathogen?
A microorganism that enters the body and causes communicable disease
Name the 4 pathogens
Bacteria
Virus
Protist
Fungi
Describe a bacteria cell
Small cells that reproduce quickly (every 20 minutes from binary fission)
Prokaryotic cell
Produce toxins which make you feel ill
Describe a virus
Live inside of cells and replicate (bursting the cells)
Reproduce very quickly
The cell damage is what makes you feel ill
Describe a protist
Eukaryotes carried by vectors (parasites)
Describe a fungi organism
Unicellular OR a body made of hyphae.
Hyphae grows and penetrates human skin which causes disease.
How can pathogens be spread?
Water
Air
Direct contact
Name 3 viral diseases.
HIV
Measles
Tobacco mosaic virus
How is measles spread, what are the symptoms and how can it be prevented?
- Spread by droplets (sneeze or cough)
- Red skin rash, fever, even fatal.
- Most people are vaccinated when they are young
How is HIV spread, what are the symptoms and how can it be prevented?
- Spread by sexual contact, exchanging bodily fluids.
- Flu-like symptoms
- Antiretroviral drugs - stop the virus replicating in the body
What is tobacco mosaic virus?
A virus that causes a mosaic pattern on the leaves of the plant which causes them to become discoloured. This means the plant can’t perform photosynthesis or grow.
How do pathogens enter the body?
Respiratory system
Contaminated food/water
Cuts, wounds…
Explain the process of phagocytosis.
The phagocyte binds to the pathogen, the membrane of the phagocyte will surround the pathogen and engulf it, then the enzymes inside of the phagocyte will break down the pathogen and destroy it.
What do antitoxins do?
Neutralise toxins (poisons which make us feel ill) released by pathogens
What do antibodies do?
Bind on to specific antigens, mark it for destruction, clump pathogens together and then get engulfed by phagocytes.
What are lymphocytes?
A specific white blood cell that recognise antigens on the surface of pathogens and produce antibodies.
Lymphocytes ALSO produce memory cells after infection to remember how to fight that pathogen in the future.
What is CILIA
Cells that are hair-like projections which line the trachea, bronchi and bronchioles that waft mucus and pathogens away from the lungs
How is the stomach a defence barrier?
The stomach produces hydrochloric acid which kills the pathogen. It is a CHEMICAL barrier.
How are tears a defence barrier?
Tears contain lysozyme (an enzyme) that breaks down cell walls of bacteria. It is a CHEMICAL barrier.
How does the skin act as a defence barrier?
- Covers the body which physically prevents pathogens from entering.
- Secretes oils and antimicrobial substances that kill pathogens
Which type of pathogen can antibiotics be used to kill?
Bacteria
Why is it hard to find drugs to destroy viruses?
Viruses reproduce using body’s cells, which means drugs will also kill the body’s cells alongside the virus
How do bacteria become resistant to antibiotics?
Mutation
Why is it important you finish the whole course of antibiotics?
More resistant strains of bacteria might survive or multiply. If some bacteria multiply, they can reproduce again which will cause the infection to return.
