Health, Disease and the Development of Medicines Flashcards
How does the WHO define health?
A state of complete physical, mental, and social well being
What is a communicable disease?
A disease that can be spread between individuals
What is a non-communicable disease?
A disease that cannot be transmitted between individuals
What causes cholera? What are its effects, how does it spread, and how can you reduce transmission?
A bacterium called Vibrio cholerae
Diarrhoea
Via contaminated water sources
Using clean water supplies
What causes tuberculosis? What are its effects, how does it spread, and how can you reduce transmission?
A bacterium called Mycobacterium tuberculosis
Coughing and lung damage
Through the air by coughing
Infected people should avoid public spaces, have good hygiene, sleep alone, and have well ventilated homes
What causes malaria? What are its effects, how does it spread, and how can you reduce transmission?
A protist
Damage to red blood cells, later the liver
Mosquitos are animal vectors
Use of mosquito nets and insect repellent
What causes stomach ulcers? What are its effects, how does it spread, and how can you reduce transmission?
A bacterium called Helicobacter pylori
Stomach pain, nausea and vomiting
Oral transmission e.g. swallowing contaminated water or food
Having clean water supplies and hygienic living conditions
What causes ebola? What are its effects, how does it spread, and how can you reduce transmission?
Ebola virus
Haemorrhagic fever
Via bodily fluids
Isolating infected individuals and sterilising areas where the virus may be present
What causes chalara ash dieback? What are its effects, how does it spread, and how can you reduce transmission?
A fungus that infects ash trees
Leaf loss and bark lesions
Carried through the air by the wind and when diseased trees are moved
Removing young infected ash trees and replanting them with different species and restricting the import or movement of ash trees
What is the lytic pathway?
A way viruses reproduce in cells, by attaching itself to a specific host cell and injecting its genetic material into the cell. The virus then uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of new viruses. The viral components assemble and the host cell splits open, releasing the new viruses, which infect more cells.
What is the lysogenic pathway?
A way viruses reproduce in cells, when the injected genetic material is incorporated into the genome (DNA) of the host cell. The viral genetic material gets replicated along with the host DNA every time the host cell divides, but the virus is dormant and no new viruses are made. Eventually a trigger (e.g. the presence of a chemical) causes the viral genetic material to leave the genome and enter the lytic pathway.
What causes chlamydia? What are its effects, how does it spread, and how can you reduce transmission?
A kind of bacterium that behaves similarly to a virus as it can only reproduce inside host cells. It does not always cause symptoms but can result in infertility. Wear a condom during sex and screen individuals so they can be treated.
What causes HIV/AIDS? What are its effects, how does it spread, and how can you reduce transmission?
A virus (Human Immunodeficiency Virus) that kills white blood cells, eventually leading to AIDS (Acquired Immune Deficiency Syndrome), where a person’s immune system deteriorates and eventually fails, so a person becomes vulnerable to other infections. It is spread by some bodily fluids (e.g. blood, semen, vaginal fluids). Use a condom during sex, avoid sharing needles, and screen often and get treatment.
What are some plant physical defences?
Leaves and stems have a waxy cuticle, which provides a barrier to stop pathogens entering and pests from damaging them, as well as water collecting on them, reducing the risk from water borne pathogens
Plant cells are surrounded by cell walls, which forms another physical barrier
What are some plant chemical defences?
Antiseptics, which kill bacterial and fungal pathogens
Chemicals which deter pests from feeding on their leaves
What are some plant chemicals used to help humans?
Quinine - comes from the bark of the cinchona tree, for years was the main treatment for malaria
Aspirin - found in the bark and leaves of willow trees, used to relieve pain and fever
How can plant diseases be detected?
Observations - plant pathologists recognise symptoms such as galls to determine the disease
Distribution - patches of diseased plants could show it is spread through the soil and a random distribution may suggest an airborne pathogen
Laboratory testing
How can a plant disease be differentiated from an environmental cause?
Changing the environmental conditions (e.g. adding nutrients to the soil) and observing any change in the plant symptoms
How is detecting antigens used for diagnosing plant diseases?
Pathogens have unique antigens on their surface, so they will be present in a plant infected with the pathogen and detected in a sample of tissue. This allows the pathogen to be identified and the disease diagnosed.
How is detecting DNA used for diagnosing plant diseases?
A pathogen’s DNA will be present in an infected plant’s tissues. Scientists can detect even small amounts of this DNA in a sample, allowing them to identify the particular pathogen that is present.
What are some physical barriers in the body to stop pathogens?
Skin is a barrier and blood clots quickly seal cuts to keep microbes out
Hairs and mucus in the nose trap particles that contain pathogens
Cells in the trachea and bronchi produce mucus to trap pathogens, while other cells have cilia, which waft the mucus to the throat, where it can be swallowed
What are some chemical barriers in the body to stop pathogens?
The stomach produces hydrochloric acid, which kills most swallowed pathogens
The eyes produce lysozyme in tears, which kills bacteria on the surface of the eye
