Topic 5 - Health, disease and development of medicines Flashcards
What is a disease?
A condition where part of an organism doesn’t function properly.
What are antigens?
A foreign organism that gets into the body and triggers an immune response such as proteins on the surface of pathogens
What are Lymphocytes? (6)
Lymphocytes are another type of white blood cell. They recognise antigens. Lymphocytes detect that both the proteins and pathogens are foreign, not naturally occurring within your body and produce antibodies. This can take a few days, during which time you may feel ill. The antibodies created by the lymphocytes cause pathogens to stick together, and make it easier for phagocytes to engulf them.
Which chemicals that are used as chemical defences in plant help treat humans? (2)
Quinine comes from the bark of the cinchona tree. For years it was the main treatment for malaria.
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 you catch a communicable diseases?
When you are exposed to a pathogen
What do antihypertensives do?
They reduce blood pressure. Prevents damage to arteries so reduces risk of fatty deposits. However, has side-effects such as headaches
Describe Stomach Ulcers
Pathogen - Helicobacter Pylori
Symptoms - stomach pain, nausea and vomiting
How it spreads - Oral transmission (eating)
How to reduce transmission - Having clean water supplies and hygienic living conditions
How do Phagocytes engulf pathogens?
The phagocytes’ membrane surrounds the pathogen and the enzymes found inside the cell, then break down the pathogen in order to destroy it. As phagocytes do this to all pathogens that they encounter, we call them ‘non-specific’.
Describe Ebola
Pathogen - Ebola virus
Symptoms - Haemorrhagic fever
How it spreads - Via bodily fluids
How to reduce transmission - Isolating infected individuals and sterilising any areas a virus may be present.
What do statins do?
They reduce cholesterol in the blood. Slows build-up of fatty deposits. Reduces risk of heart attack and stroke. However, there can be severe side-effects - liver damage.
How do cell walls help defend a plant?
Forms a physical barrier against the pathogen if they make it past the waxy cuticle.
What are the effects of non-communicable diseases? (3)
> In areas of high levels or obesity, smoking or alcohol consumption there is likely to be high occurrence of non-communicable disease which can put pressure on resources of local hospitals.
Sometimes people with non-communicable diseases are unable to work which can affect the economy
The high cost and high occurrence of these diseases can hold back the development of these countries - so they have an effect on a global level
Describe Tuberculosis
Pathogen - Mycobacterium tuberculosis
Symptoms - Lung damage
How it spreads - Air when infected cough
How to reduce transmission - Infected people should avoid crowded spaces, practise good hygiene and sleep alone - homes should be well-ventilated.
What is the Lysogenic pathway?
No new viruses are made by it is combined with the host cell’s DNA which means that it is replicated when it the host cell divides.
What does detecting an specific antigen in plant tissue allow?
Pathogens have unique molecules on their surface called antigens. Antigens from a particular pathogen will be present in a plant infected with that pathogen and 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 idenfified and the disease diagnosed.
What aseptic techniques are needed to sterilise equipment to investigate the effects of antibiotics on bacterial growth? (5)
- Autoclave (high temp and pressure to kill any microorganisms) for Petri dishes and growth medium
- Inoculating loop should be passed through a hot flame before being used to transfer bacteria to remove unwanted microorganisms.
- Liquid bacterial cultures should be kept in a culture vial with a lid. The lid should only be removed briefly when transferring the bacteria, to prevent other microbes getting in.
- The Petri dish should have a lid taped on after the practical to prevent other microorganisms from the air getting in.
- The Petri dish should be stored upside down to stop drops of condensation falling onto the agar.
Describe the steps of the lytic pathway
The virus simply replicates its genetic material by using the host’s cells and enzymes. After this, new viruses are formed when components assemble together. The host cell then burst open to release the new viruses (lysis). The cycle starts agains when the new viruses infect other cells.
How are monoclonal antibodies used to target drugs to cancer cells?
1) An anti-cancer drug is attached to monoclonal antibodies.
2) The antibodies are given to the patient through a drip.
3) The antibodies target specific cells (the cancer cells) because they only bind to the tumour markers. and radiotherapy) can affect normal body cells
4) The drug kills the cancer cells but doesn’t kill any normal body cells near the tumour.
5) Other cancer treatments (like other drugs as well as killing cancer cells
6) So the side effects of an antibody-based drug are lower than for other drugs or radiotherapy.
How were new drugs discovered?
In the past, drugs were discovered purely by chance such as penicillin by Alexander Fleming. Nowadays, most scientists use their knowledge of how a disease works to try and identify molecules that could be used as drugs to fight disease.
What are pathogens?
Pathogens are organisms such as viruses, bacteria, fungi and protists that cause communicable diseases.
What are memory Lymphocytes and why are they useful?
6
They can ‘remember’ the antigens from an infection by a previous pathogen. A second exposure to it will result in a much faster immune response. Antibodies will be produced much faster, which often stops us becoming ill again. There are hundreds of common colds caused by different viruses. It is very unlikely you will become infected by the same virus because memory lymphocytes exist to fight the infection immediately. This response to a known antigen is called the secondary response and it is much quicker than the response to an antigen for the first time.
What are the disadvantages of immunisation?
- Doesn’t always work - doesn’t give you immunity
- Could give you bad reactions - swelling - but not always
What are the two ways to identify specific pathogens in a lab?
Detecting antigens
Detecting DNA
Describe chemical barriers in humans.
Hydrochloric acid - kills most pathogens that are swallowed.
Lysozyme (in tears) - kills bacteria that is on the surface of the eye.
Describe how coronary bypass surgery can be used to treat cardiovascular disease.
If part of a blood vessel is blocked, then a piece of healthy blood vessel is taken from elsewhere in the body and used to create an alternative route to the the blocked section.
What are anticoagulants?
They reduce chance of blood clots. This can cause excessive bleeding when you are cut.
What is blind testing and double blind testing in clinical testing? (3)
Blind - when the patient doesn’t know whether they’re getting the drug or the placebo.
Double blind - Neither the doctors or the patients know who had the placebo or the drug. This is so that the doctors monitoring the patients and analysing the results aren’t subconsciously influenced by their knowledge.
