Biology π | Diseases & Immunity | 10 Flashcards
Define pathogen.
A microscopic, single-celled, disease-causing organism
What is a transmissible disease?
A disease in which the pathogen can be passed from one host to another.
What are the four types of pathogens?
Viruses, Bacteria, Fungi, Prokaryotes
A pathogen can be transmitted in two types of contact. What are they?
By direct contact, or indirect contact.
In what ways can a pathogen be transmitted by direct contact?
By blood, sexual activity, or other body fluids.
In what ways can a pathogen be transmitted indirectly?
From contaminated surfaces, food, animals, and air.
What is the innate immune system?
The non-specific immune system that targets anything foreign.
What is the adaptive immune system?
The specific immune system that has antibodies targeting specific pathogens.
What are the physical barriers to pathogens?
- Cilia and mucus in the trachea moves pathogens up the throat
- Oil is produced on the skin
- Blood clots form to prevent pathogens entering the body through open wounds
What are the chemical barriers to pathogens?
- Hydrochloric acid in the stomach is secreted that kills bacteria in food.
- White blood cells
Why is a clean water supply important in controlling the spread of disease?
In contaminated water, diseases such as cholera or diarrhoea can be spread.
What are the different ways of controlling the spread of disease?
- Clean water supply
- Hygienic food preparation
- Good personal hygiene
- Waste disposal
- Sewage treatment
What is active immunity?
Defense against a pathogen by antibody production in the body
What is an antigen?
Proteins that project from the cell membrane of a pathogen.
What are antibodies?
A protein with a particular shape that binds to an antigen produced by white blood cells.
What is the type of white blood cell that produces antibodies?
Lymphocytes.
Define epitope.
The binding site of antibodies and antigens.
How can active immunity be gained?
By catching the disease, or getting a vaccine.
How can food be prepared to prevent the spread of disease?
- Wash hands before eating
- Keep animals away
*Food shouldnβt be kept at room temperature for too long - Food should be cooked at high temperature
- Raw meat should be cooked and kept away from other foods
How does bacteria build up on our skin?
We produce oil when our bodies are hot, and if the oil and dirt is left on the skin for too long, bacteria breed and unpleasant smells are created. In our mouths, some can cause bad breath and tooth decay.
How can personal hygiene be practiced to prevent the spread of disease?
- We should wash regularly, using soaps and shampoos to remove oils
- We should brush our teeth twice a day and perhaps use mouthwash to remove harmful bacteria.
How can unsafe landfill sites lead to the multiplication of pathogens?
In an unsafe landfill site, rubbish is piled up and bacteria breed in waste food. This causes dangerous chemicals to seep out of the rubbish and pollute the landscape. Some decomposers, especially bacteria, produce methane which is flammable if allowed to build up.
How can good waste disposal prevent the spread of disease?
- It can be made so that only licensed operators are allowed to add material to the site, the rubbish checked so that nothing is dangerous
- The rubbish can be placed in even layers and compacted to reduce space.
- Pipes can be placed to allow methane to harmlessly escape.
How can sewage contain many pathogens?
Raw, untreated sewage runs off of streets, comes from toilets, and from factories: With these many other substances, running into rivers untreated, it can harm people and our environment.
Specific antibodies have __ for particular antigens
complementary shapes
How can passive immunity be gained?
Being provided antibodies from outside the body
- Breastfeeding
- Across the placenta
- Injection of antibodies
What are memory cells?
When a lymphocyte clones itself, not all of them make antibodies: some of them remain in the blood. They are prepared, when the same kind of pathogen enters the body, to quickly kill that pathogen with an immune response.
How does a vaccine work?
- Weakened pathogens or their antigens are put into the body
- Antigens stimulate an immune response by lymphocytes, producing antibodies
- Memory cells remain, giving long term immunity
Is passive or active immunity long-term? Why?
Active immunity is long term as your body retains memory cells. Passive immunity simply injects the antibodies without letting the body create memory cells.
What is cholera?
A disease that is caused by a bacteria transmitted in contaminated water.
How does cholera harm oneβs body?
The bacterium multiplies in the small intestine, secreting a toxin that stimulates the cells lining the intestine to produce chloride ions: These ions fill up the lumen, which lowers the water potential (lower than blood). Water moves out of the blood and into the lumen by osmosis, which leads to dehydration.
