Infection and Response Flashcards
What is a pathogen?
A disease causing mircoorganism.
How can a virus cause disease?
Viruses live and reproduce inside cells, causing cell damage.
How can bacteria cause disease?
When bacteria reproduce, they produce toxins, which damage tissues.
What are three viral diseases and their effects?
Measles: fever and red skin rash.
HIV: flu-like symptoms, leads to aids.
Tobacco mosaic virus: affects growth due to lack of photosynthesis.
What are two bacterial diseases and their effects?
Salmonella: fever, abdominal cramps, vomiting and diarrhoea.
Gonorrhoea: Yellow discharge from the penis or vagina.
What are three fungal diseases?
Rose black spots, athletes foot and thrush.
How do fungal diseases spread?
Touching another object that has the infection or by touching surfaces where the fungus is present.
How are fungal diseases treated?
Antifungal medications can treat fungal diseases by killing or stopping the growth of fungi in humans, animals, and plants.
Which disease is caused by a protist?
Malaria.
How can diseases interact?
- Defects in the immune system.
- Viruses living in cells.
- Immune reactions caused by pathogens causing allergies: rashes and asthma.
- Physical illness leading to mental illness.
How is malaria spread?
Through the blood after bitten by an infected mosquito.
How can malaria be prevented?
Vaccinations, avoiding mosquito bites and taking antimalarial medication.
What are the four lines of defence against infection?
Skin, nose, trachea and bronchi (by producing mucus) and stomach.
What are the two types of white blood cells?
Phagocytes and lymphocytes.
How do lymphocytes destroy pathogens?
Lymphocytes produce antitoxins that bind to the toxins produced by some pathogens (usually bacteria), neutraling the toxins. Lymphocytes produce antibodies that target and help to destroy specific pathogens by binding to antigens (proteins) on the pathogens’ surfaces.
How do phagocytes destroy pathogens?
Phagocytes are attracted to areas of infection. The phagocyte surrounds the pathogen and engulfs it. Enzymes that digest and destroy the pathogen are released.
How does a vaccine work?
Intoduce small quantities of dead or inactive pathogen, white blood cells are stimulatied to produce antibodies. If the same pathogen re-enters the body, white cells respond quickly, destroying the pathogen.
What is the use of antibiotics?
To cure bacterial diseases by killing infective bacteria inside the body.
What is the use of painkillers?
They are used to treat symptoms of a disease.
What are the stages in drug development?
- Preclinical testing uses cells, tissues, and living animals to test for toxicity at dosages.
- Clinical trials using healthy volunteers to test toxicity at different doses.
- Using larger groups to test effectiveness and toxicity at different dosages.
How are clinical trials carried out?
- Very low doses of the drug are given at the start of the clinical trial.
- If the drug is found to be safe, further clinical trials are carried out to find the optimum dose for the drug.
In ‘blind trials’, patients are unaware of dose and ‘double blind’ trials, neither patient nor doctor is aware of dose, some patients are given a placebo.
What is the role of a placebo?
It is a fake drug to test for the effectiveness of the real drug in comparisons.
What are monoclonal antibodies?
Human-made, identical copies of one type of antibody.
How are monoclonal antibodies used to test for pregnancy?
They are attached to the end of a pregnancy test stick. If she is pregnant, HCG will be present in her urine and will bind to the monoclonal antibodies on the test stick, causing a change in colour or pattern, indicating pregnancy.
How do plants prevent disease?
By closing their stomatas or increasing thickness of cell walls.
How are plants affected by a lack of nitrate?
They will have stunted growth and yellowing of leaves.
How are plants affected by a lack of magnesium?
The plant is limited in terms of its photosynthetic ability, and the plant growth is compromised with leaves turning yellow while the veins may remain green.
