B3: infection and response Flashcards
What is a bacterium?
A bacterium is a very small living cell
What is a virus?
A virus is an infective agent made up of DNA.
What is a protist?
A protist is a single celled eukaryote that causes disease.
What is a fungi?
A fungi can be single- or multi-cellular, and have hyphae that can grow, penetrate skin and produce disease-causing spores.
What is a pathogen?
A pathogen is a microorganism that causes disease.
How do viruses cause disease?
Viruses infiltrate cells and replicate themselves using the cells machinery, until the cells burst and the clones spread to other cells. The damage to cells what makes us feel ill.
How do bacteria cause disease?
Bacteria cause disease by producing toxins that damage cells and tissues.
How do protists cause disease?
Protists make us feel ill by damaging our tissues, and are often transferred to us by vectors.
How do fungi cause disease?
- Replication of the fungus (fungal cells can invade tissues and disrupt their function)
- Immune response (by immune cells or antibodies)
- Competitive metabolism (using the nutrients meant for the host body)
Give three examples and symptoms of viral diseases.
- Measles: Rash, fever.
- HIV: Flu-like symptoms, then symptoms can disappear but virus still present.
- Tobacco Mosaic Virus: Causes a mosaic pattern and discoloration on leaves.
Give one example and symptoms of a fungal disease.
- Rose black spot: Causes purple or black spots on leaves, then leaves can turn yellow and drop off, affecting the plant’s ability to photosynthesise.
Give one example and symptoms of a disease caused by a protist.
- Malaria: causes repeating episodes of fever, sweats and chills, headaches.
Give two examples and symptoms of bacterial diseases.
- Salmonella: causes fever, cramps, vomiting, and diarrhoea.
- Gonorrhoea: pain when urinating, green or yellow discharge from genitalia.
How is measles spread?
Droplets from an infected person’s sneeze or cough.
How is HIV spread?
Sexual contact, or exchanging bodily fluids with an infected person.