Topic 5 - Health, Diseases And The Development Of Medicines Flashcards
How does the World Health Organisation (WHO) define health?
“A state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity”
What is a communicable disease?
A disease that can be spread between individuals.
What is a non-communicable disease?
A disease that can’t be transmitted between individuals
What are pathogens?
Organisms such as viruses, bacterial, fungi and protists that cause communicable diseases
What is cholera caused by?
A bacterium called Vibrio cholerae
What are the symptoms of cholera?
Diarrhoea
How is cholera spread?
Contaminated water sources
How do you reduce/prevent transmission of cholera?
Making sure that people have clean water supplies
What is tuberculosis caused by?
A bacterium called Mycobacterium tuberculosis
What are the symptoms/effects of tuberculosis?
Coughing and lung damage
How is tuberculosis spread?
Through the air when infected individuals cough
How do you reduce/prevent transmission of tuberculosis?
Infected people should avoid crowded public spaces, practise good hygiene and sleep alone. Their homes should also be well-ventilated
What is malaria caused by?
A protist
What are the effects of malaria?
Damage to red blood cells and in sever cases to the liver.
How is malaria spread?
Mosquitos act as animal vectors (carriers) - they pass on the protist to humans but don’t get the disease themselves.
How do you reduce/prevent transmission of malaria?
Use of mosquito nets and insect repellent to prevent mosquitos carrying the pathogen from biting people.
What are stomach ulcers caused by?
A bacterium called Helicobacter pylori
What are the symptoms of stomach ulcers?
Stomach pain, nausea and vomiting
How are stomach ulcers spread?
Oral transmission e.g. swallowing contaminated water or food
How do you reduce/prevent transmission of stomach ulcers?
Having clean water supplies and hygienic living conditions
What is ebola caused by?
Ebola virus
What are the symptoms of ebola?
Haemorrhagic fever (a fever with bleeding)
How is ebola spread?
Bodily fluids
How do you reduce/prevent transmission of ebola?
Isolating infected individuals and sterilising any area where the virus may be present
What is chalara ash dieback caused by?
A fungus that infects ash trees.
What are the symptoms of chalara ash dieback?
Leaf loss and bark lesions (wounds)
How is chalara ash dieback spread?
Carried through the air by the wind and when diseased ash trees are moved between areas.
How do you reduce/prevent transmissions of chalara ash dieback?
Removing young, infected ash tress and replanting with different species and restricting the import or movement of ash trees
What is a virus?
They’re usually no more than a protein coat around a strand of genetic material
How do viruses reproduce?
They have to infect living cells called host cells.
What happens in the lytic pathway?
1) The virus attaches itself to a specific host cell and injects its genetic material into the cell
2) The virus uses proteins and enzymes in the host cell to replicate its genetic material and produce the components of new viruses
3) The viral components assemble
4) The host cell splits open, releasing the new viruses, which infect more cells
What happens in the lysogenic pathway?
1) The injected genetic material is incorporated into the genome of the host cell
2) The viral genetic material gets replicated along with the host DNA every time the host cell divides - but the virus is dormant (inactive) and no new viruses are made
3) 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 are STIs?
Infections that are spread through sexual contact, including sexual contact
What is clamydia?
A kind of bacterium but it behaves in a similar way to a virus because it can only reproduce in host cells
How can the spread of chlamydia be reduced?
Wearing a condom when having sex, screening individuals so they can be treated for the infection or avoiding sexual contact
What can chlamydia cause?
Infertility in men and women
What does HIV stand for?
Human Immunodeficiency Virus
What does HIV do?
Kill white blood cells which are important in the immune response
What will HIV eventually lead to?
AIDS - Acquired Immune Deficiency Syndrome
What happens when someone gets AIDS?
An infected person’s immune system deteriorates and eventually fails - because of this, the person becomes very vulnerable to opportunistic infections by other pathogens
How is HIV spread?
Bodily fluids
How can you prevent the spread of HIV?
Use condoms when having sex, avoid sharing needles
What do plants have as a physical barrier?
Most leave and stems have a waxy cuticle?
How does having a waxy cuticle help plants defend themselves from disease?
It provides a barrier to stop pathogens entering them or pests from damaging them. It may also stop water collecting on the leaf, which could reduce the risk of infection by pathogens that are transferred between plants and water
Which cellular structure of a plant is a physical defence?
The cell walls made from cellulose - these form a physical barrier against the pathogens that make it past the waxy cuticle
What other type of defence do plants use?
Chemical
What do they produce to kill bacterial and fungal pathogens?
Antiseptics
What else do plants produce chemicals against?
They produce chemicals to deter pests from feeding on their leaves
How can plant chemicals help humans?
Some can be used as drugs to treat human diseases or relieve symptoms
Give two plant chemicals that have been used to treat human disease/receive symptoms?
Quinine and aspirin
Where does Quinine come from and what does it help?
It comes from the bark of the cinchona tree. For years it was the main treatment of malaria
Where does aspirin come from and what is it used for?
It was developed from a chemical found in the bark and leaves of willow trees. It’s used to relieve pain and fever.
How can plant pathologists identify the kind of pathogen involved in plant diseases?
Analysing the distribution of diseased plants
How does the skin act as a physical barrier to the skin?
If it gets damages, blood clots quickly seal cuts to keep microorganisms out
How do hairs and mucus act as a physical barrier in the nose?
They trap particles that could contain pathogens
Apart from the nose, what else produces mucus?
Cells in the trachea and bronchi
Why are cilia in the trachea and bronchi important?
They waft the mucus up to the back of the throat where it can be swallowed
What does the stomach produce as a chemical barrier and what does it do?
The stomach produces hydrochloric acid which kills most pathogens swallowed
What does the eye produce as a chemical barrier and what does it do?
The eyes produce a chemical called lysozyme (in tears) which kills bacteria on the surface of the eye
What happens if pathogens make it into your body?
The immune system kicks in to destroy them
What is the most important part of the immune system?
White blood cells
How do bacteria make us feel unwell?
Release toxins
What are the three ways white blood cells can destroy pathogens?
- Digesting it
- Producing antibodies
- Producing antitoxins
What is phagocytosis?
The white blood cell detects the chemicals released by an antigen and moves towards it. It engulfs it and digests it using lysosomes/hydrolytic enzymes.