SB5 - Health, Disease, and the Development of Medicines Flashcards
SB5a
1) Define the term health.
2) Define the term disease.
3) Describe how communicable and non-communicable diseases differ
1) Health is a state of complete physical, mental and social well-being.
2) Diseases are illnesses that affect an organism’s body, organs, tissues or cells.
3) Communicable diseases can be transferred from one person to another, or from one organism to another.
Non-communicable diseases are not transferred between people or other organisms.
SB5a
1) Outline the role of the immune system in protecting against disease
2) Explain how disease can affect the immune system
3) Define risk factor
1) The immune system protects the body from pathogens. If a pathogen gets past the first line of defence (the non-specific defences), the immune system works to stop or minimise infection.
2) A disease can damage the immune system, which makes it easier for other pathogens to cause disease.
3) A risk factor is a factor associated with an increased likelihood of getting a disease.
SB5b
1) Give examples of non-communicable diseases.
2) Define the term malnutrition.
3) Explain how diet can lead to malnutrition.
1) Non-communicable diseases include: cancer, diabetes, genetic diseases and conditions, and heart disease.
2) Malnutrition occurs when you get too little or too much of particular nutrients from your food.
3) A poor diet can mean that you are consuming a lack or too much of certain nutrients, which leads to malnutrition.
SB5b
1) Describe the link between alcohol and liver disease.
2) Explain the effect of alcohol consumption and obesity at local, national and global levels.
1) When alcohol is broken down by the liver, toxic products are released. Too many of these toxic products can cause permanent liver damage.
2) - Obesity and alcohol consumption are risk factors for other non-communicable diseases. For example obesity can result in type 2 diabetes, and alcohol can result in liver disease.
- More diseases results in more pressure on the resources of local hospitals and the NHS as a whole to treat people with obesity and related health issues.
- More disease means that less people in society will be able to work and contribute to the economy.
- Alcoholism also increases violence, antisocial behaviour and accidents, as well as increasing treatment costs to the NHS
SB5c
1) Describe the two ways in which obesity is measured, and what are the formulae?
2) Describe how obesity correlates with cardiovascular disease
3) Describe how smoking correlates with cardiovascular disease
4) Why may BMI be misleading when assessing the risk of developing obesity-related disorders?
1) BMI stands for body mass index, and predicts the amount of fat in the body. If your BMI is 30 or above, you are obese.
The formula for BMI is weight (kg) / (height (m) squared)
Waist to hip ratio (WHR) is used by dividing the waist measurement by the hip measurement.
2) Obesity leads to high blood pressure and the build-up of fatty deposits in the arteries, which lead to cardiovascular disease. Therefore, being obese is a risk factor for cardiovascular disease.
3) Tobacco smoke contains many harmful substances that damage the artery lining. This causes fat to build up at the site of damage, making the artery narrower. Therefore, a blood clot may block the artery here, or break off and block an artery in another part of the body, causing a heart attack or stroke.
4) A person’s body mass may be high in relation to their height because they have a lot of muscle rather than fat. This would mean that they have a high BMI but are not likely to be at risk of developing obesity-related disorders.
SB5c
1) Explain why exercise and diet affect obesity.
2) Compare how cardiovascular diseases are treated (medication, stents, and heart transplants)
1) A poor diet and lack of exercise can lead to obesity. This is because eating too much saturated fat and not burning the fat through exercise can can cause fat to build up below the skin and around the organs, which causes obesity.
2) Medication: Statins are drugs that help to lower cholesterol in the blood.
Anticoagulants make blood clots less likely.
Stents: Coronary arteries that are blocked or have become narrow can be stretched open and a stent inserted to maintain blood flow to the heart.
The benefits that are surgery is quick and the stents can last a long time. The issues are that surgery has risks, such as the risk of infection to bleeding, and a blood clot can occur near the stent.
Heart transplants: A heart transplant is required in cases of heart failure. Coronary heart disease can lead to heart failure. This is where heart fails to pump sufficient blood and organs are starved of oxygen.
The issues are that trying to find a new human biological heart takes a long time, and the heart could be rejected.
Artificial hearts don’t work very well and are only temporary. However, a benefit is that they can’t get rejected.
SB5d
Explain how signs of a disease can be used to identify the pathogen
The process to identify a disease may include the following steps:
1) Following a report of a possible infection, scientists will visit the location.
2) To avoid any confusion it is essential they look at other factors that might cause similar symptoms. For example, damage to leaves might be caused by a pathogen or grazing animals.
3) The scientists will try to identify any environmental causes such as pollution that might be affecting the plants.
4) Finally they will photograph the symptoms and take samples for laboratory analysis.
SB5e
1) State the ways in which pathogens can be spread.
2) Explain how the spread of different pathogens can be reduced or prevented in 4 different ways of spreading
1) The ways that pathogens are spread: direct contact, air, water, vector, unprotected sexual activities and bodily fluids.
2) Water: prevented by good hygiene, boiling water before use, treating water chemically to kill bacteria, and only drinking bottled water.
Direct contact, air: keep infected people separated from others; cut down and burn infected trees, or maybe restrict the import of ash trees to prevent any infected trees entering the country
Unprotected sexual activities and bodily fluids: use a condom, don’t share needles because there is a risk of injecting bodily fluids from the previous user of the needle.
Vector (eg. Mosquitoes): Sleep under mosquito net, spraying standing water with insecticides to kill the vector.
SB5f
1) Describe the structure of a virus.
2) Explain how viruses differ from cells.
3) Describe the lytic pathway of a virus life cycle
1) They contain one or more strands of genetic material surrounded by a protein coat called a capsid.
2) Viruses cannot replicate on their own like other cells; they need to invade a host cell and use their cell components to make new virus cells. They cannot replicate on their own because they don’t have the components/ proteins and enzymes necessary to reproduce by themselves.
3) A. The virus injects its genetic material into the host cell
B. It then uses proteins and enzymes in the host cell to replicate its genetic material and produce components of new viruses.
C. The viral components then assemble into new viruses.
D. Then, the host cell splits open releasing new viruses, and other nearby cells can then be infected with the virus.
SB5f
1) Describe the lysogenic pathway of a virus life cycle.
2) Compare and contrast the lytic and lysogenic pathways.
3) How do you calculate the cross-sectional area of viral cultures and clear agar jelly?
1) The lysogenic cycle: The virus injects its DNA into the host cell and the DNA becomes incorporated into the host DNA
As the host cell replicates, the viral DNA replicates also, but no new virus particles are made during this time (the virus is dormant).
An environmental change acts as a trigger for the viral DNA to exit the genome of the host. Then the viral DNA enters the lytic cycle so the proteins of the host cell are used to make new components of the virus.
2) In the lytic cycle, the viruses infect the host cell and uses its metabolism to multiply, causing the lysis or death of the cell. Whereas, the lysogenic cycle consists of a virus that lies dormant, and the host cell is reproducing instead.
3) Formula: cross sectional area = πr²
You measure to the centre of the cross-sectional area.
SB5g
1) Describe 2 physical barriers of plants to pests and pathogens.
2) Describe some chemical defences of plants to pests and pathogens.
3) Describe how plant protective chemicals are used to treat human diseases or symptoms.
1) Physical barriers stop pathogens from entering and damaging an organism. They include: the waxy cuticle of leaves, and layers of dead cells (eg. the bark on stems).
2) Plants produce chemical substances such as poisons or insect repellents. They either kill some pathogens, or deter pests from feeding on their leaves.
3) Aspirin used as pain relief comes from an acid produced by willow trees.
SB5g
1) Describe examples of aseptic technique.
2) Explain why aseptic technique is used during the culture of microorganisms.
1) Using autoclaves to sterilise equipment and growth medium (eg. flaming the necks of bottles)
2) Tests on bacterial and human cells need to avoid contamination by other microorganisms in the air. Aseptic techniques help to avoid this. Contamination will affect the results of the experiment.
SB5h
1) Describe how plant diseases are detected using visible symptoms.
2) Describe how environmental causes of plant problems are eliminated when identifying disease.
1) The visible symptoms can be matched to a gardening manual, and used to identify the cause of the disease.
2) Eliminating possible environmental causes – a plant may be showing symptoms due to deficiencies in the environment for example, lack of nutrients. If a nutrient deficiency is suspected, the nutrients can be added to the soils of the affected pants, and observe whether or not the symptoms disappear. By changing the environment and supplying the plant with the nutrients, you can identify whether the symptoms were due to the lacking nutrients or if they were because of a specific disease.
SB5h
1) Describe how distribution analysis can help identify a plant disease.
2) Describe how plant pathogens are diagnosed in the lab.
1) Different pathogens disperse in different ways, so the distribution of the infected plants may indicate what method of dispersal is used by the pathogen. Patches of diseased plants may suggest infection through the soil, while random distributions may suggest airborne transmission.
2) Monoclonal antibodies that are complimentary to the antigens on the bacteria are added to the infected plant tissue sample in the diagnostic test. These are antibodies that are specific to the antigens on the pathogen. If the antigen is present in the infected plant sample, the antibodies will bind to them and allow accurate diagnosis of the disease.
SB5i
1) Explain how the spread of the STIs Chlamydia and HIV can be reduced or prevented.
2) Why may a person be symptomless for a long time after the initial period of infection by HIV?
3) Explain why a person with AIDS become seriously ill due to infection by another pathogen
1) Chlamydia is a disease caused by bacteria that may result in infertility. Chlamaydia is transmitted by bodily fluids. Therefore, using a condom prevents the mixing of bodily fluids during sexual intercourse. HIV is a virus that eventually leads to a disease called AIDS in the people it infects. They are most commonly spread by sexual contact, and a method to prevent it spreading is using a condom during sex.
2) After entering cells, HIV enters the lysogenic stage of its life cycle and becomes dormant. Therefore, the virus is not active and will not be causing any symptoms in the infected person.
3) HIV kills white blood cells, which are an important part of the immune response, so the immune system is weakened. This means that the person is more vulnerable to infection by other pathogens.
SB5i
1) Describe how physical barriers protect the body
2) Describe how chemical barriers protect the body
3) What is meant by a ‘specific immune response’?
1) The skin covers almost all parts of your body to prevent infection from pathogens. If it is cut or grazed it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier.
The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus. This traps pathogens before they can enter the lungs. When the nose is blown, mucus is removed and any pathogens are trapped within it.
The lungs: The cells that line the trachea also have hairs called cilia, which are much smaller than those in the nose. These are called ciliated cells. The ciliated cells waft their hairs in a motion like a Mexican wave at a football match and move mucus and pathogens upwards towards the throat where it is swallowed into your stomach. Other cells called goblet cells create the mucus in order to trap pathogens. The production of mucus in your airways is a physical barrier.
2) The eyes produce tears which contain enzymes called lysosomes. This kills bacteria on the surface of the eye.
The hydrochloric acid in the stomach kills pathogens that reach the stomach.
3) A ‘specific immune response’ is the immune response to a specific pathogens.
SB5j
1) What is the role of the immune system?
2) What does it mean if a person is immune to a disease?
2) Describe how antigens trigger the release of antibodies and the production of memory lymphocytes, including how it looks on the graph
3) Describe the role of antibodies in the immune response.
1) The immune system protects the body by attacking pathogens.
2) The immune system can respond quickly if the pathogen which causes the disease enters their body again.
3) The first exposure to the pathogen is shown on the graph right before the antibodies are produced and the graph line goes up. Lymphocytes bind to antigens and produce specific complementary antibodies. Then, the antibodies defend against pathogens. They bind on the pathogen’s antigen and directly destroy them. Lymphocytes can also produce antitoxins. These antitoxins can also neutralise the toxins released by the pathogen. Memory lymphocyte production is also triggered. The point when it is produced is show on the graph after the first pathogen exposure by a horizontal, dashed line. At the time of second exposure (right before the second curve) the body has some memory lymphocytes that will recognise the pathogen’s antigens, and trigger more antibodies to be made. This means antibodies will be produced much more quickly (shown by a steeper curve) following the exposure, and the curve will be steeper.
4) Antibodies are produced by the lymphocytes to target and neutralize pathogens and toxins. They recognize and bind to the complementary antigens on specific pathogens so that they can be destroyed.
SB5j
1) Describe the role of memory lymphocytes in triggering a secondary response.
2) Explain how immunisation protects against infection by a pathogen.
3) Discuss advantages and disadvantages of immunisation
1) Memory lymphocytes (also known as B-lymphocytes) detect antigens on a pathogen in the blood. B-lymphocytes produce specific antibodies, which lock onto the pathogen and destroy it. The antibodies are produced rapidly and flow throughout the body to find all similar pathogens.
2) - A weakened form of a pathogen which cannot cause disease is injected into someone.
- This causes lymphocytes to make and then release complementary antibodies to attack and kill the specific antigen that was injected.
- Some memory lymphocytes remain in the bloodstream which can produce the specific antibody for the antigen.
- If the body is infected by the real pathogen, the memory lymphocytes will release antibodies to fight off the pathogen and quickly destroy it.
3) Advantages of immunisation:
- Less likely to get a disease from a pathogen
- Develop herd immunity, which keeps vulnerable unvaccinated individuals safe
- Possibly eradicate the pathogen
- Vaccination is cheaper than treating a sick patient.
Disadvantages of immunisation:
- Possible side effects
- Poor vaccine distribution, not everyone can receive or afford it
- Low vaccination rates within certain groups due to religious and ethical reasons
SB5l
1) Define the term monoclonal antibody.
2) Define the term hybridoma cell.
3) Describe how monoclonal antibodies are produced by lymphocytes.
1) Monoclonal antibodies are identical copies of one type of antibody. They are specific to one type of antigen, and engineered by scientists.
2) A hybridoma cell is a cell where lymphocytes are combined with a particular type of tumour cell.
3)- An antigen is injected into a mouse. (Scientists must first inject the animal with an antigen so that the animal makes B-lymphocytes which produces antibodies that are complementary to the antigen that’s injected.)
- The mouse naturally produces lymphocytes, which produce antibodies specific to the antigen.
- Spleen cells which produce the lymphocytes are removed during a small operation.
- The spleen cells are fused with human cancerous white blood cells called myeloma cells to form hybridoma cells which divide indefinitely. (Tumour cells are used because tumor cells divide rapidly, so using them means the hybridoma cell will divide rapidly to produce many clones, which can produce more of the monoclonal antibodies.)
- These hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen.
SB5l
1) Explain how monoclonal antibodies are used in pregnancy testing.
2) Explain how monoclonal antibodies are used in diagnosis of disease (including blood clots and cancer).
3) Explain the advantages of monoclonal antibodies compared with drug and radiotherapy treatments to target cells.
1) During pregnancy, a woman begins to produce hCG hormone, which becomes present in her urine. To use the test, the woman should urinate on the patch containing the blue beads. If hCG is present in her urine, then the monoclonal antibodies on the blue beads will attach to the hormone. The urine carries the beads and the hormone to the test strip, where they bind to the antibodies secured on the strip. The test strip will then turn blue, showing a positive result.
2) Cancer: When injected into a person’s body, the monoclonal antibodies will bind with these cancer cells and clump them together. This makes it easier to identify a cancerous tumour , which can then be treated or removed.
The monoclonal antibodies are also used in the diagnosis of the cancer. The antibodies are made slightly radioactive. The antibodies then attach to the cancer cells and then radiation can be detected using a PET scanner, for example.
Blood clots: Monoclonal antibodies have been developed that bind to the proteins which form blood clots. These antibodies can be labelled with a radioactive element and injected into the bloodstream. A camera which detects radiation can then be used to visualise where the antibodies have accumulated, and so the position of any blood clots.
3) Monoclonal antibodies allow the specific targeting of drugs to cancer cells. This means that fewer body cells are affected compared with normal drug and radiotherapy treatments, so there are fewer side effects.
SB5k
1) Define the term antibiotic
2) Explain why antibiotics are useful for treating bacterial infections
3) Explain why antibiotics cannot be used to treat infections by pathogens other than bacteria.
1) Antibiotics are substances that slow down or stop the growth of bacteria.
2) Antibiotics kill or prevent the growth of bacterial cells but they do not harm human cells.
3) Antibiotics are designed to kill only bacteria, not other pathogens. Viruses can only reproduce inside their host’s cells. This means that it is very hard to develop drugs which target the virus but not the cells of the host.
SB5k
1) Describe the stages of development of new medicines.
2) What are the three things which are investigated during the preclinical testing of drugs?
3) Why are very low doses of the drug given at the start of clinical trials?
1) Preclinical drug trials (stage 1): The drugs are tested using computer models and human cells grown in the laboratory.
Animal trials (stage 2): Drugs that pass the first stage are tested on animals.
Human clinical trials (stage 3): Drugs that have passed animal tests are used in clinical trials. They are tested on healthy volunteers to check that they are safe. If this is successful, they will test it on a small amount of patients who the drug was produced for.
2) Toxicity: how harmful the drug is (side effects)
Efficacy: how well the drug works (effectiveness)
Dosage: how much of the drug is given
3) Low doses of the drug are used initially in case the drug has any harmful effects. If this is safe the dosage increases until the optimum dosage is identified.
SB5k
1) What are blind and double-blind trials?
2) What are placebos?
3) Define preclinical
1) In blind trials, the doctor knows which patients have been given the drug and which have been given the placebo, but the patients do not know.
In double blind trials, neither the doctor nor the patient knows who has been given the drug or placebo. This ensures that neither the patients nor the doctors are able to subconsciously influence the results of the trials.
2) A placebo is an inactive substance that looks like the drug but does not do anything.
3) Preclinical is the stages of drug testing before testing the drug on a human. The drug is tested on human cells and animals.
SB5j
1) Why is an immunised person less likely to develop a disease?
2) Why might a person get vaccinated before travelling to another country?
3) What are the two types of white blood cells?
4) Explain herd immunity
1) The person would respond to the vaccine by producing antibodies and memory lymphocytes. Because of this, if the pathogen enters their body again, their immune system will recognise the foreign antigens and respond more quickly, meaning they will be more likely to eradicate the pathogen before it causes the disease.
2) To prevent bringing diseases to the country that they are travelling to, to prevent getting a disease while in the country, and to prevent bringing a disease back to their own country.
3) There are two types of white blood cell called phagocytes and lymphocytes. Phagocytes surround any pathogens in the blood and engulf them. Lymphocytes produce antibodies which kill the pathogens, and antitoxins which neutralise the effect of the pathogen’s toxins.
4) If many people in a population are immunised, then there will be fewer people who are likely to catch the disease and pass it on to others. This is herd immunity. This means that even is some individuals cannot be immunised, they are less likely to come into contact with someone with the disease and so are less likely to catch it.
