Topic 5 Flashcards
What is the World Health Organisation’s (WHO) definition for health?
“A state of complete physical, mental and social well being and not merely the absence of infirmity or disease”
What is infirmity?
Weakness or frailness, commonly due to old age
What is disease?
Disease is a condition in which part of an organism does not function properly
What are two types of disease?
Communicable and noncommunicable disease
What are communicable diseases?
Communicable diseases are diseases that can be spread between individuals
What are non- communicable diseases?
Non-communicable diseases are diseases that cannot be transmitted between individuals
If you are affected by one disease, what may happen?
If you are affected by one disease it can make you more susceptible to other diseases - your immune system may become weakened by the disease, so it is less able to fight off other diseases
What are pathogens?
Pathogens are organisms such a viruses, bacteria, fungi and protists that cause communicable diseases
What are the communicable diseases you need to know?
Cholera Tuberculosis Stomach Ulcers Chlamydia HIV Ebola Malaria Chalara Ash Dieback
What pathogen causes Cholera?
A bacterium called Vibrio cholerae.
What pathogen causes Tuberculosis?
A bacterium called Mycobacterium tuberculosis.
What pathogen causes Stomach ulcers?
A bacterium called Helicobacter pylori.
What pathogen causes Chlamydia?
A bacterium called Chlamydia trachomatis
What pathogen causes HIV?
A virus.
What pathogen causes Ebola?
The Ebola virus
What pathogen causes Malaria?
A protist
What pathogen causes Chalara ash dieback?
A fungus
What are the symptoms of Cholera?
Diarrhoea.
What are the symptoms of Tuberculosis?
Coughing and lung damage.
What are the symptoms of Malaria?
Damage to red blood cells and, in severe cases, to the liver.
What are the symptoms of Stomach ulcers?
Stomach pain, nausea and vomiting.
What are the symptoms of Ebola?
Haemorrhagic fever (a fever with bleeding).
What are the symptoms of Chalara ash dieback?
Leaf loss and bark lesions (wounds).
What are the symptoms of Chlamydia?
Although it doesn’t always cause symptoms, it can result in infertility in men and women.
How is Cholera spread?
Via contaminated water sources
How is Tuberculosis spread?
Through the air when infected individuals cough
How is malaria spread?
Mosquitoes act as animal vectors (carriers) - they pass on the protist to humans but don’t get the disease themselves.
How are Stomach ulcers spread?
By oral transmission, e.g. By swallowing contaminated water or food
How is Ebola spread?
Via bodily fluids
How is Chalara ash dieback spread?
It is carried through the air by the wind. It also spreads when diseased ash trees are moved between areas.
How can Cholera be reduced?
By making sure that people have access to clean water supplies.
How can Tuberculosis be reduced?
Infected people should avoid crowded public spaces, practise good hygiene and sleep alone. Their homes should also be well-ventilated.
How can malaria be reduced?
By the use of mosquito nets and insect repellent to prevent mosquitoes carrying the pathogen from biting people.
How can stomach ulcers be reduced?
By having clean water supplies and hygienic living conditions
How can ebola be reduced?
By isolating infected individuals and sterilising any areas where the virus may be present
How can Chalara ash dieback be reduced?
Removing young, infected ash trees and replanting with different species. Restricting the import or movement of ash trees
What does being susceptible to a disease mean?
You are more likely to get the disease
What are viruses?
Usually no more than a protein coat around a strand of genetic material
How do viruses reproduce by the lytic pathway/cycle?
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 the new viruses
3) the viral components assemble
4) the host cell splits open, releasing the new viruses which infect more cells
How do viruses reproduce?
By infecting living cells (host cells), specific types of viruses will only infect specific cells
What does it mean if a virus is dormant?
It is inactive
How do viruses reproduce in the lysogenic pathway/cycle?
- GM is incorporated into genome of host cell
- Viral GM and host DNA replicate when host cell divides but virus remains inactive. (no new viruses being made)
- Trigger (chemical) causes GM to leave genome and enter the lytic pathway
What are the two STIs you need to know about?
HIV and Chlamydia
Some STIs are not only spread by sexual intercourse but what else? Give an example of an STIs which is spread in this way.
Chlamydia, genital contact
What are the lytic and lysogenic pathways /cycles?
Parts of the life cycle of a virus
What is HIV?
- the Human Immunodeficiency Virus
- A virus which kills white blood cells (these are needed to trigger an immune response, so it can make a person very vulnerable to infections by other pathogens)
How is HIV spread?
Through bodily fluids
How can the spread of HIV be prevented?
Use a condom during sex. Drug users should avoid sharing needles, an infected person should be screened so they have receive proper treatment and medication.
What are some examples of bodily fluids which could be infected by HIV and therefore could spread HIV?
Blood, semen, vaginal fluids
What does HIV lead to?
AIDS
What is AIDS
Acquired Immune Deficiency Syndrome
How can medication reduce the spread of HIV?
Medication can reduce the risk of an infected individual passing the virus on to others during sex or a mother passing the virus on to her baby during pregnancy, however this means that screening is important to identify the infected individuals for treatment
What physical defences/barriers do plants have against pathogens and pests?
- most plants leaves and stems have a waxy cuticle
* plant cells are surrounded by cell walls
How does a waxy cuticle act as a physical barrier for plants against pathogens and pests?
- The waxy cuticle provides a barrier to stop pathogens entering the plant and to prevent pests damaging the plant.
- a waxy cuticle may also stop water from collecting on the leaf, this could reduce the risk of infection by pathogens that are transferred between plants in water
How does a cell wall surrounding plant cells act as a physical barrier for plants against pathogens and pests?
The cell walls form a physical barrier against pathogens that make it past the waxy cuticle
What is the function of antiseptics in plants?
Acts as a chemical defence against pathogens, kills bacteria and fungal pathogens
What are two chemicals from plants which can be used as drugs to treat human diseases or relieve symptoms?
- Quinine
* Aspirin
Where is quinine found in plants?
The bark of the cinchona tree
How is quinine used to treat human disease?
For years quinine was the main treatment for malaria
How is aspirin used to relieve symptoms of human disease?
To relieve pain and fever
How is aspirin developed from plants?
It is developed from a chemical found in the bark and leaves of willow trees
In the field how are plant diseases usually detected?
By observations, plant pathologists recognise the symptoms
How are plant diseases detected and identified in the field?
- Through observations. (looking at symptoms)
- Analysing distribution of affected plants (e.g random distribution may suggest airborne pathogen)
- Eliminating environmental causes
What is an example of a symptom of a disease that could indicate that the disease is due to environmental causes?
Yellow leaves
How is it possible to determine whether a plant is diseased or if the symptoms were due to something else?
By changing the environmental conditions (e.g. adding nutrients to the soil) and observing any change in the plant’s symptoms
What is an example of an environmental cause?
Nutrient deficiency
How can plant pathologists identify the type of pathogen involved in causing a disease?
By analysing the distribution of the diseased plants
What are two examples of how analysing the distribution of diseased plants can help to identify the type of pathogen causing the disease?
- patches of diseased plants may suggest that the disease is spread through the soil
- a random distribution of diseased plants may suggest an airborne pathogen
What would diseased patches of plants suggest about the causes of a disease?
The disease is spread through the soil
What type of pathogen would be suggested with a random distribution of diseased plants?
Air borne pathogen
What allows accurate identification of specific pathogens?
Laboratory-based diagnostic testing
What two things could laboratory-based diagnostic testing involve?
- detecting antigens
* detecting DNA
How can detecting antigens be used to detect pathogens in plants?
they can be detected in a sample of plant tissue (monoclonal antibodies) and as they are unique to a certain pathogen, the pathogens can be identified and the disease diagnosed
How can detecting DNA identify pathogens in infected plants?
A pathogens DNA would be present in the plants tissue, which can be detected through special techniques. This would allow for the particular pathogen present to be identified
How do the physical barriers in the body protect us from pathogens?
- Skin - barrier to pathogens. (blood clots deal cuts to keep microorganisms out)
- Hair and Mucus (in nose, trachea and bronchi) trap particles that could contain pathogens
- Contains cilia to waft mucus back up throat and away from lungs
What are the chemical barriers that defend us against pathogens?
- Stomach has HCL that kills most pathogens swallowed
2. Eyes produce lysozyme in tears which kill bacteria on surface of the eye
What are B-lymphocytes?
B-lymphocytes help protect the body against pathogens
How do B-lymphocytes protect us from pathogens?
When they come across an antigen, they produce proteins called antibodies. These lock on to the antigens so they can be destroyed. antibodies are then produced rapidly and flow around he body to find other similar pathogens
What are memory lymphocytes?
Antigens trigger production of memory lymphocytes. they stay in the body and remember a specific antigen. Therefore, they make a person immune as their system is able to respond much quicker to transmitted pathogens.
How can a person be immunised through the use of an inactive form of a pathogen?
- Inject a dead or inactive pathogen into the body
- The body will make antibodies to destroy them even though they are inactive. (they have antigens)
- The antigens also trigger memory lymphocytes
- So if the pathogen enters the body again, the memory lymphocytes can cause a faster secondary immune response
What are the pros of immunisation?
- They prevent epidemics as even those who aren’t immunised are less likely to catch it as there as less people to pass it on. (Herd Immunity)
- Some diseases, e.g smallpox, have been wiped out due to immunisation
What are the cons of immunisation?
It doesn’t always give you immunity and it may sometimes give allergic reactions (swelling, fever, seizures)
What can antibiotics only be used to treat?
Bacterial infections as antibiotics only inhibits processes in bacterial cells, and not in the host organism
Explain some aseptic techniques used in culturing microorganisms in the lab.
- Petri dishes and growth mediums must be sterilised before use. Can be done by using an autoclave (uses steam at a high pressure and temp to kill and microorganisms present)
- Before being used to transfer bacteria, inoculating loop should be sterilised by putting it through hot flame
- Liquid bacterial cultures should be covered kept in a vial with a lid. Keep closed unless transferring bacteria
- After transferring bacteria, Petri dish should be covered with tightly taped lid to stop micros from air getting in.
- Store dish upside down to stop condensation falling into agar
How can you grow bacteria in a lab?
- You grow them in a growth medium (solid agar jelly) in a petri dish. (can use an inoculating tube to transfer micros)
- Should form visible colonies, as they have multiplied, on surface of agar jelly
- Keep micros at 25 as harmful pathogens are less likely to grow at this temp. (scientists are able to though to provide optimum conditions for growth.
What is the equation used to calculate cross-sectional areas of bacterial cultures and agar jelly?
πr2
What is preclinical testing?
(after discovering the drug) Preclinical testing - Drugs are tested on human cells and tissues in the lab. (dont use it on drugs that affect whole or multiple body systems. Then use on live animal to see if the drug works, how toxic it is and for best dosage
What is clinical testing?
- Using healthy volunteers to make sure there are no harmful side effects when the body if working properly
- If this works, can be tested on ill volunteers. Optimum dose is found.
- Patients are put into 2 groups. One is given the drug, other is given a placebo
- Can be double-blind where the patients nor the dr know which drugs which group is getting. This is so the results aren’t subconsciously influenced by their knowledge
- If it passes all of these steps, must be approved by a medical agency before it can be given to patients
What is the use of lymphocytes in monoclonal antibodies?
- Monoclonal antibodies are produced by lots of clones of a single B lymphocyte
- As they dont divide easily, a mouse B-lymphocyte is fused with a tumour myeloma cell, which divide very easily, to make a hybridoma.
what do hybridomas do?
Hybridomas can be cloned to get lots of identical cells. these can then divide quickly to produce monoclonal antibodies as they divide. They are then collected and purified
Why are monoclonal antibodies useful?
- You can make monoclonal antibodies that bind to anything you want. e.g an antigen that’s only found on the surface of one type of cell.
- They are useful as they will only bind to (target) this molecule. This means you can use them to target a specific cell or chemical in the body
What hormone is found in the urine of women when they are pregnant?
human chorionic gonadotropin (hCG). hCG is a hormone produced by the placenta and is usually only present in a woman’s body when she is pregnant.
Briefly describe how pregnancy tests work?
- The bit of the stick that you wee on has some antibodies to the hormone. (with blue beads attached)
- The test strip has more antibodies to the hormone stuck onto it. (to make sure the hormone cant move)
- When pregnant, the hormone in the urine binds onto the blue beads and it moves up the stick and attaches itself onto the test strip. (the hormone helps it stick)
- The blue beads make the test strip turn blue
What happens if a women is not pregnant?
The urine will still move up the stick with the blue beads, but there is no hormone to make the blue beads stick onto the strip. Therefore, it wont turn blue
How can you make monoclonal antibodies that target cancer cells?
Cancer cells have proteins on their cell membranes called tumour markers. In the lab, you can make monoclonal antibodies that will bind to these tumour markers
How can monoclonal antibodies be used to diagnose cancer?
- They are labelled with a radioactive element
2, These are given to a patients blood through a drip, so it can be carried around the body - When they spot a cancer cell, they bind to the tumour markers
- A picture of the body is taken with a camera that detects radioactivity and cancer cells would show up as a bright spot
- We can see where the cancer is, the size of it, and if its spreading
How can monoclonal antibodies target drugs to cancer cells?
1
An anti-cancer drug is attached to monoclonal antibodies and given to a patient through a drip
- The antibodies target these specific cancer cells and bind to the tumour marker
- The drug kills the cancer cells but not the normal body cells near the tumour
How can monoclonal antibodies target drugs to cancer cells?
- An anti-cancer drug is attached to monoclonal antibodies and given to a patient through a drip
- The antibodies target these specific cancer cells and bind to the tumour marker
- The drug kills the cancer cells but not the normal body cells near the tumour
Why is it better to use monoclonal antibodies in treating cancer than other drugs and radiotherapy?
The alternatives can affect normal body cells as well as killing the cancer cells, giving the alternatives more side effects
What happens when blood clots?
Proteins in the blood join together to form a solid mesh
How can monoclonal antibodies be used to find blood clots?
- Monoclonal antibodies have been developed to bind to these proteins
- Attach a radioactive element to these antibodies and inject them into the body
- Take a picture using a camera that detects radioactivity
- The blood clots will appear on the picture as a bright spot
What are risk factors?
Things that are linked to an increase in the likelihood that a person will develop a certain disease
What is cardiovascular disease?
Any disease associated with the heart or blood vessels
What risk factor is associated with cardiovascular disease and why?
Smoking
- Nicote in the smoke increases heart rate and blood pressure
- High blood pressure damages artery walls, which contributes to a build up of fatty deposits in the arteries. These restrict blood flow and increase the ridk of a heart attach/stroke
- Increases the risk of blood clots forming in arteries which can restrict blood flow, causing a heart/stroke
What other risk factors are associated with cardiovascular disease?
- Drinking too much
- Lack of exercise
- Obesity
- A diet in high saturated fat
What risk factor affects the liver?
Drinking too much alcohol as alcohol is broken down by enzymes in the liver and some of the products are toxic. Persistent drinking can cause permanent liver damage
Are non-communicable diseases usually caused by a number of factors, or just one?
They are caused by several different factors interacting with each other. Including diseases such as cancer, liver and lung diseases
How can non-communicable diseases affect local areas?
In areas where there are high levels of obesity , smoking, or excessive alcohol consumption, there’s likely to be a high occurrence of certain non-communicable diseases. This can put pressure on hospital resources.
How can non-communicable diseases have an effect on a national level?
The NHS provides the resources for the treatment of patients all over the UK. The people suffering from non-communicable diseases may not be able to work. This can affect a country’s economy
How can non-communicable diseases have an effect on a global level?
They are very common. In developing countries, malnutrition is a big problem because people are not able to access food. The high cost and occurrence of these diseases can hold back the development of a country
What is a body mass index?
It is something which is used as a guid to help decide whether someone is underweight, normal, overweight or obese
How is BMI calculated?
Weight (kg) / Height (m) squared
How does exercise and diet affect obesity and malnutrition?
If you eat a high fat, high sugar diet and you dont do enough exercise, you’re more likely to take in more energy than you use, storing this excess energy as fat. This can give you a higher BMI
What is the waist-to-hip ratio equation and what does it mean?
Waist-to-hip ratio = Waist circumference / hip circumference
The higher your ratio, the more weight you’re likely to be carrying around your middle. A ratio above 1.0 for males and above 0.85 for females indicates that you’re carrying too much weight around your middle
How can lifestyle changes be used to treat cardiovascular disease?
- They can reduce the risk of getting CVD and helps to reduce the risk of having a further heart attack/stroke for those who do have CVD
- People may be encouraged to:
- eat a healthy diet (low in saturated fat)
- Exercise regularly
- Lose weight if necessary
- Stop smoking
How can statins be used as a lifelong medication for cardiovascular disease?
Statins reduce the amount of cholesterol in the bloodstream. This slows down the rate at which fatty deposits form, and therefore reduces the risk of heart attacks and strokes.
What are the negatives of using statins?
They can sometimes cause side effects e.g. aching muscles. Some of these side effects can be serious e.g. liver damage
How can anticoagulants be used as a lifelong medication for cardiovascular disease?
They make blood clots less likely to form
What are the negatives of using anticoagulants?
It can cause excessive bleeding if the person is hurt in an accident
How can antihypertensives be used as a lifelong medication for cardiovascular disease?
They reduce blood pressure. This helps to prevent damage to blood vessels and so reduces the risk of fatty deposits forming
What are the negatives of using antihypertensives?
They can cause side effects e.g. headaches and fainting
How can stents be used in a surgical procedure to reduce the risk of cardiovascular disease?
Stents are tubes that are inserted in arteries. They keep them open, making sure blood can pass through to the heart muscles. This lowers the risk of a heart attack
What are the negatives of using stents?
Over time, the artery can narrow again as stents can irritate the artery and make scar tissue grow. The patient also has to take drugs to stop clotting on the stent
How can healthy vessels be used in a surgical procedure to reduce the risk of cardiovascular disease?
If part of a blood vessel is blocked, a piece of healthy vessel can be used to bypass the blocked section. This is coronary bypass surgery
How can a donor heart be used in a surgical procedure to reduce the risk of cardiovascular disease?
The whole heart can be replaced with a donor heart
What are the negatives of using a donor heart?
The new heart does not always start pumping properly and drugs have to be taken to stop the body rejecting it. These drugs can have side effects e.g. making you more vulnerable to infections
