Section 5 - Health, Disease and the Development of Medicines Flashcards
What is the World Health Organisation definition of health?
Complete physical, mental and social well-being, and not merely the absence of disease or infirmity.
What is a disease?
A condition where part of an organism doesn’t function properly.
What are the two sorts of disease?
Communicable and non-communicable.
What is a communicable disease?
A disease that can be spread between individuals.
What is a non-communicable disease?
A disease which cannot be spread between individuals.
How does having a disease affect your chances of developing another?
It increases since the body is weakened. The immune system is busy fighting off one disease so the body cannot as easily defend against more diseases.
What are pathogens?
Organisms, such as some viruses, bacteria, fungi and protists, that cause communicable diseases.
What are some examples of communicable diseases?
Cholera Tuberculosis Malaria Stomach Ulcers Ebola Chalara Ash Dieback
What is Cholera? What causes it? What are its symptoms? How does it spread? How can its spread be reduced or prevented?
A communicable disease that affects humans.
Caused by the bacterium Vibrio cholerae.
Its main symptom is diarrhoea.
It spreads via contaminated water sources.
it can be prevented by making sure people have access to clean water supplies.
What is Tuberculosis? What causes it? What are its symptoms? How does it spread? How can its spread be reduced or prevented?
A communicable disease that affects humans.
Caused by the bacterium Mycobacterium tuberculosis.
Its main symptoms are coughing and lung damage.
It spreads through the air when infected individuals cough.
To reduce and prevent its spread infected individuals should avoid crowded public spaces, practice good hygiene, sleep alone and make sure their homes are well ventilated.
What is Malaria? What causes it? What are its symptoms? How does it spread? How can its spread be reduced or prevented?
A communicable disease that affects humans.
It is caused by a protist.
Its main symptoms are damage to red blood cells and in severe cases the liver.
It is spread by using mosquitoes as an animal vector, they pass it on to humans but don’t get the disease themselves.
To prevent and reduce the spread of the disease people should put up mosquito nets, and use insect repellents to prevent malaria-carrying mosquitoes from biting people.
What are Stomach Ulcers? What causes them? What are their symptoms? How do they spread? How can their spread be reduced or prevented?
A communicable disease that affects humans.
They are caused by the bacterium Helicobacter pylori.
Their main symptoms are stomach pain, nausea and vomiting.
They are spread orally when swallowing contaminated water and food.
The spread can be prevented by having clean water supplies and hygienic living conditions as well as making sure all food is properly cooked.
What is Ebola? What causes it? What are its symptoms? How does it spread? How can its spread be reduced or prevented?
A communicable disease that affects humans.
It is caused by the Ebola virus.
Its main symptom is Haemorrhagic fever (a fever with bleeding).
It is transmitted via bodily fluids.
Its spread can be reduced and prevented by isolating infected individuals and sterilising any areas where the virus may be present.
What is Chalara Ash Diebach? What causes it? What are its symptoms? How does it spread? How can its spread be reduced or prevented?
A communicable disease that affects ash trees.
It is caused by a fungus that infects ash trees.
Its main symptoms are leaf loss and bark lesions.
It spreads by the air and is carried by the wind, similarly, it can spread when infected trees are moved between areas.
Its spread can be reduced and prevented by removing young, infected ash trees and replanting with different species, it can also be prevented by the restriction of the import or movement of ash trees.
How do viruses reproduce?
They infect living cells and use them to reproduce.
What are the two parts of the virus life cycle?
The lytic pathway and the lysogenic pathway.
What happens in the lytic pathway of the virus life cycle?
The virus attaches itself to a specific host cell and injects its genetic material into the cell.
The virus uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of new viruses.
The viral components then assemble.
The host cell splits open releasing more viruses which go on to infect more cells.
What happens in the lysogenic pathway of the virus life cycle?
Following the virus’ injection into the cell during the first stage of the lytic pathway, its DNA incorporates itself into the genome. of the host cell.
The viral genetic material is replicated along with the host DNA during cell division, but the virus is dormant, so it doesn’t actively produce new viruses.
This can repeat numerous times.
Eventually, a trigger, like the presence of a specific chemical, causes the viral genetic material to leave the genome and resume the lytic pathway.
What are STIs?
Sexually transmitted infections, they spread through sexual contact, including sexual intercourse.
What is chlamydia? What is it caused by? What are some of its symptoms? How is it spread? How can its spread be prevented or reduced?
A communicable disease, more specifically an STI.
It is caused by the bacterium Chlamydia trachomatis.
Its main symptoms include random and abnormal discharges from the genitals as well as infertility in both sexes.
It is spread through sexual contact.
Its spread can be prevented through the use of condoms, screening individuals so they can be treated for the infection and the complete avoision of sexual contact.
What is HIV? What is it caused by? What are some of its symptoms? How is it spread? How can its spread be prevented or reduced?
A communicable disease, more specifically an STI.
It is caused by the Human Immunodeficiency Virus.
Its main symptom is AIDS, Acquired Immune Deficiency Syndrome, because the virus attacks white blood cells.
It is spread through bodily fluids.
Its spread can be prevented through the use of condoms, drug users should avoid sharing needles and medication can reduce the risk of an infected individual passing on the virus during sex, so screening and proper treatment are also important.
How do plants defend themselves physically against pathogens and pests?
Most plant leaves and stems have a waxy cuticle which provides a barrier to stop pathogens from entering the plant and stop pests from damaging them. This also prevents water from building up on the leaves, which reduces transmission of waterborne pathogens.
Plant cells themselves are surrounded by cell walls made from cellulose to provide a physical barrier against the pathogens that do make it past the cuticle.
How do plants defend themselves chemically against pathogens and pests?
many plants produce chemicals to prevent damage to the plant, such as antiseptics to kill off bacterial and fungal pathogens, they also produce pest deterrents such as toxins or repellents.
How have plant chemicals been used in medicine?
Quinine comes from the bark of the cinchona tree and it was the main treatment for malaria for many years.
Aspirin is used to relieve pain and fever, it was developed from a chemical found in the bark and leaves of willow trees.
How can plant diseases be detected in the field?
In the field plant diseases are normally discovered by observation, plant pathologists recognise the symptoms such as galls, abnormal growths, which may indicate crown gall disease in many types of plant.
Some plants may show symptoms of diseases caused by environmental conditions. By changing the environmental conditions, such as adding more nutrients to the soil, and observing the change it is possible to determine if the plant was infected or if the symptoms were something else.
Pathogens spread in different ways, by analysing the distribution of diseased plants it is possible to identify the type of pathogen responsible, patches of infection may suggest soil and contact transfer whereas random distribution could suggest that the pathogen is airborne.
How can plant pathogens be detected in the lab?
The identification of unique antigens and the detection of pathogen DNA.
How are plant pathogens detected through the identification of unique antigens?
Pathogens have unique proteins on their surface called antigens, these antigens will be present in a plant infected by that pathogen, which can be detected in a sample of plant tissue using monoclonal antibodies. The detection of an antigen unique to a particular pathogen allows that pathogen to be identified and the disease to be diagnosed.
How are plant pathogens detected through the detection of pathogen DNA?
If a plant is infected with a pathogen, its DNA will be present in the plant’s tissues.
Scientists can use various techniques to detect even small amounts of pathogen DNA in a sample of plant tissue allowing them to identify the particular pathogen that is present and to diagnose the disease.
What physical barriers does the human body have to prevent pathogens from entering the body?
The skin acts as a physical barrier.
Blood clots seal cuts to prevent pathogens from entering the body.
Hairs and mucus in the nose trap particles that could contain pathogens.
Cells in your trachea and bronchi produce mucus to trap pathogens and other cells in the airways have cilia which waft the mucus up to the back of the throat so that it can be swallowed.
What chemical barriers does the human body have to prevent pathogens from entering the body?
The stomach produces hydrochloric acid which kills most swallowed pathogens.
The eyes produce the chemical lysozyme in tears which kill bacteria on the eyes surface.
How does the immune system combat pathogens?
White blood cells travel around the body in search of pathogens.
B-lymphocytes are a type of white blood cell that is involved in the specific immune response.
How does the specific immune response work?
Every pathogen has unique molecules on its surface called antigens.
When a B-lymphocyte comes across an antigen on a pathogen they start to produce proteins called antibodies, which bind to the invading pathogen so it can be found and destroyed by the other white blood cells. the antibodies produced are specific to that pathogen and won’t affect any other pathogen.
Why does the body’s first response to a pathogen take a long time?
The body has never dealt with that pathogen before, so it had to create enough of the specific antibody to overcome the disease.
Why does the body’s later responses to a pathogen take much less time than the first response?
When the body interacts with a foreign antigen, it produces memory lymphocytes as well as antigens, these memory lymphocytes stay in the body for a long time and “remember” a specific antigen.
The person is then immune to that pathogen since the body can react quickly to a second infection.
If the same pathogen enters the body again, there are more cells that will recognise and produce antibodies against it so the second response is both faster and stronger than the first, and will often remove the pathogen before the infectee display any symptoms.
How does medical immunisation take place?
A dead or inactive form of the pathogen is injected into the body, they’re antigenic so the body will still produce antibodies to destroy them despite them being harmless.
This also produces memory lymphocytes so if a live version of that type of pathogen were to get into the body there will already be the necessary memory lymphocytes in place to begin a rapid secondary immune response.
This makes it less likely for someone who has been immunised to ever show symptoms of the disease.
