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| Question | Answer |
|---|---|
| What is an antigen? | a protein on the surface of a cell that is unique to the cell |
| How does the immune system recognise foreign microorganisms? | their antigens are different to those of the cells of the body they have invaded |
| Which cells respond to foreign antigens? | white blood cells |
| How do white blood cells respond to foreign antigens? | they make antibodies that inactivate or destroy the invading pathogen |
| What is a memory cell? | a memory cell is a white blood cell that 'remembers' how to recognise a specific pathogen by its antigen and how to make the antibodies needed to fight it |
| What happens when a person contracts a disease for the first time? | after the pathogen is detected by its antigen, the immune system works out what antibodies are needed to combat the pathogen and how to produce it |
| Why is the immune system sometimes not able to protect against a disease the first time a person is infected? | the pathogen reproduces and acts faster than the body can work out what antibodies to make and how |
| Why is the second infection of a disease much less traumatic than the first time? | the immune system is able to produce antibodies immediately because of the memory cells produced during the first time preventing the disease from taking hold |
| Why does a person after immunisation not get sick when carrying pathogens from a fatal disease like meningitis? | immunisation leaves the person with memory cells that can produces antibodies extremely quickly stopping the pathogen from breeding and acting |
| Name the process of making a person immune to a disease? | vaccination |
| How do vaccines work? |
• a small amount of the dead or inactivated pathogen is injected into the body • the white blood cells then respond making antibodies and producing memory cells • if the live pathogen is later encountered by the immune system, the memory cells fight it off effectively |
| Name two bacterial diseases that are prevented by vaccine. | tetanus and diptheria |
| Name three viral diseases that are prevented by vaccine. | polio, measles, and mumps |
| Name a disease wiped out by vaccination. | small pox |
| Name a disease close to eradication by vaccination. | polio |
| What does the MMR vaccine protect against? | measles, mumps, and rubella |
| What is herd immunity? | a large proportion of the population is immune, making it is difficult for the pathogen to spread ao protecting unvaccinated people and those with a compromised immune system |
| Why is herd immunity important? | to protect people who have yet to be vaccinated or have compromised immune systems like cancer patients undergoing chemotherapy and new born babies |
| What can damage herd immunity? | fewer people being vaccinated |
| Give an example when herd immunity was damaged in the UK. | in the 1970s because of a scare about the whooping cough vaccine, vaccination rates fell from 80% to 30% and many children got the disease with a substantial number dying |
| Was the 1970 scare about the whooping cough vaccine justified? | no, the vaccine was as safe as any medicine |
| What is the WHO target on measles? | for 95% of children to have two measles vaccinations to produce global herd immunity |
| Question | Answer |
|---|---|
| What do medicines for infectious diseases treat? | (1) the symptoms, and (2) the disease |
| Name two painkillers. | paracetamol and aspirin |
| What will painkillers do for a person with a bad cold or flu? | it will relieve a headache or sore throat |
| What will painkillers not do for a person with a bad cold or flu? | it will have no effect on the viruses that cause the cold and have entered the tissues |
| If the painkillers have no effect on the viruses causing a cold, how does the person get well again? | the immune system will eventually overcome the virus |
| What can be used to kill bacteria outside the body? | antiseptics and disinfectants |
| What do antiseptics kill? | microorganisms in the environment |
| Could antiseptics and disinfectants be used to used to kill bacteria in the body? | no, as they are poisonous to human beings so would cause a person to feel very sick, possibly even die |
| Name the medicines used to kill bacteria inside the body. | antibiotics |
| Name the first antibiotic. | penicillin |
| What do antibiotics kill? | bacteria in the body |
| When did antibiotics first become readily available? | in the 1940s |
| How do antibiotics work? | they damage the bacterial cells making them die or unable to reproduce |
| What impact do antibiotics have on the host? | they have no impact on the cells of the host |
| How are antibiotics administered? | as a pill, a syrup, or by injection |
| Do all antibiotics work on all bacterial pathogens? | some antibiotics kill a wide range of bacteria while others are very specific and only work on one specific bacteria |
| What has been the biggest impact of antibiotics? | antibiotics have greatly reduced deaths from infectious diseases |
| Can antibiotics be used to cure diseases caused by viruses? | no, antibiotics cannot kill viral pathogens so have no effect on diseases caused by viruses |
| What do viruses do inside the body? | viruses invade the cells of the body and use them to reproduce, damaging and killing them in the process |
| Why is it difficult to develop drugs to kill viruses? | it is difficult to attack and kill viruses without damaging and killing cells because viruses live inside the cells |
| What is the biggest concern about antibiotics in the 21st century? | strains of bacteria that are resistant to antibiotics have evolved |
| What is the impact of antibiotic resistance of bacteria? | it means that many antibiotics can no longer be used to cure disease |
| What are the long term implications of antibiotic resistance? | if new antibiotics or treatments are not found, there may come a time that there will be no cure for bacterial diseases and many millions of people will begin to die of diseases that are not life threatening today |
| Why are bacteria becoming resistant to antibiotics? |
• overuse - instead of only using antibiotics for serious illness, they are often prescribed to make patients feel good about being treated • people not completing a course of antibiotics prescribed by a doctor • poor cleaning - when cleaning is not thorough, the 'fittest' survive |
| Question | Answer |
|---|---|
| Where were drugs found traditionally? | from plants or microorganisms such as moulds |
| What has changed? | today scientists often adapt chemicals from microorganisms, plants, and animals to make more effective drugs |
| What drugs are extraccted from drugs? |
• digitalis • digoxin |
| What are digitalis and digoxin used for? | to strengthen the heartbeat |
| What is aspirin used as? | a painkiller |
| Where does aspirin originate? | from a compound found in the ark of the willow tree |
| What is the chemical name for modern aspirin? | acetyl salicyclic acid |
| Who first synthesised acetyl salicyclic acid and when? | Felix Hoffman in 1897 |
| What is the difference between the chemical extracted from willow bark and acetyl salicyclic acid? | it relieves pain and inflammation better with fewer side effects |
| Who discovered penicillin and when? | Alexander Fleming in 1928 |
| How did Alexander Fleming discover penicillin? |
• he was growing bacteria for study purposes • he left the lid off a culture plate • after a holiday, he noticed mould growing on the culture medium • he noticed a clear ring in the jelly around the mould • he realised that something associated with the mould had killed the bacteria • he named the substance penicillin after that mould that produced it • he spent several years trying to extract the substance from the mould before giving up |
| What happened to penicillin after Fleming gave up? | 10 years after Fleming gave up, Ernst Chain and Howard Florey managed to extract penicillin from mould |
| What did Chain and Florey do with the penicilling they extracted? |
• they gave it to a man with a blood infection • the man recovered almost miraculously • then penicillin ran out • the man declined and died |
| What had Florey and Chain demonstrated? | even though the man died, they demonstrated that penicillin could be used to cure bacterial infections |
| What was the next stage in the development of penicillin? | driven by soldiers dying in World War II, Florey and Chain worked with Pfizer in the US to produce penicillin on an industrial scale |
| List a problem faced when looking for new drugs to fight bacterial infections. | most chemicals that kill bacteria also damage human cells so cannot be used |
| What is the source of most modern drugs? | while the starting point may still be a chemical from plants and animals, most new drugs are synthesised by researchers working in a laboratory using chemical banks and computer models |
| Name a plant used in traditional medicine that is being investigated. | the noni fruit from Costa Rica |
| Why is the noni fruit being investigated? | it has been used in traditional medicine to treat infections and non-communicable diseases, and for food with no apparent problems |
| What has early research shown about the noni fruit? | research has shown it has antibiotic properties |
| Where are scientists now looking for microorganisms to produce new antibiotics against antibiotic-resistant bacteria? | scientists are collecting soil samples globally |
| What is the challenge with researching soil microorganims? | only about 1% can be cultivated in the lab |
| What discover has resulted from researching soil microorganisms? | a new type of antibiotic |
| Does the new antibiotic work? | it has been shown to kill all bacteria including MRSA but has only been tested in mice so far |
| Question | Answer |
|---|---|
| List the properties of a good medicine. |
• effective - it must prevent or cure a disease or at least make you feel better • safe - the drug must not be too toxic (poisonous) or have unacceptable side effects for the patient • stable - you must be able to use the medicine under normal conditions and store it for some time • successfully taken into and removed from the body - it must reach its target and be cleared from your system once it has done its work |
| How long can it take for a medicine to reach the shelves? | up to 12 years |
| What does it cost to to bring a medicine to market? | around £1700 million |
| What are the two stages of testing medicines? |
• preclinical testing • clinical trials |
| What is toxicity? | a measure of being poisonous |
| What is efficacy? | the ability to produce a desired or intended result |
| Describe the process of preclinical testing in developing a new medicine. |
• researchers identify lots of possible new drugs for a disease • the drugs are tested in the laboratory on cells, tissues, and sometimes whole organisms • the drugs are tested for toxicity and efficacy • most drugs fail at this stage • the small number of chemicals which pass the early tests are then tested on animals • the effect on whole animals, possible doses and side effects is observed |
| What happens once preclinical testing is completed? | drugs that pass animal testing move on to clinical trials |
| What are drugs tested on in clinical trials? | healthy volunteers and patients |
| Describe the process of clinical trials. |
• low doses are given to healthy people to check for side effects • if found safe, it is tried on a small number of patients to see if it treats the disease • if found to be safe and effective, bigger clinical trials are conducted to find the optimum dose for the drug • if the medicine passes all the legal tests, it is licensed so doctors can prescribe it |
| What type of trials of are used in human trials? | double blind trials |
| What is a placebo? | a substance that has no therapeutic effect |
| What is a double blind trial? |
• some people are given the medicine and some people are given a placebo • neither the patients nor the doctors know who has received the medicine and who has received the placebo |
| What is done with the results of drug tests? | they are published in journals after they have undergone peer review |
| Who decides whether medications can be prescribed by the NHS? | NICE - the National Institute for Health Care Excellence |
| What does NICE do? | it reviews published results of drug trials to decide which drugs give good value for money |
| Question | Answer |
|---|---|
| What is a hybridoma? | a hybrid cell formed by the fusion of two different types of cell, especially one capable of producing antibodies with a cancer tumour cell |
| What are monoclonal antibodies used for? | a form of medical treatment that relies on the immune system |
| What are monoclonal antibodies? | proteins that are produced to target particular cells or chemicals in the body |
| What do lymphocytes do? | they are white blood cells that produce antibodies |
| What can lymphocytes not do? | they cannot divide |
| What cells divide rapidly? | they divide rapidly making clones of themselves |
| Do all animals produce lymphocytes? | yes |
| How is a hybridoma made? | mice lymphocytes that have been stimulated to produce a particular antibody are combined with a type of tumour cell to make a hybridoma |
| Why are lymphocytes combined with tumour cells to make hybridomas? | to combine the ability of lymphocytes to make antibodies with the ability of tumour cells to divide rapidly to to produce cells that divide to make a large number of identical cells that produce antibodies |
| What is done with hybridomas? |
• hybridomas are allowed to multiply and produce antibodies • the antibodies are then collected and purified |
| What are monoclonal antibodies? | antibodies produced from a single clone of cells |
| What are antigens? | antigens are protein molecules that are often found on the surface of cells |
| How are monoclonal antibodies related to antigens? | the monoclonal antibodies produced from a single clone of cells are specific to one binding site on one specific antigen |
| Name 5 uses of monoclonal antibodies. |
• pregnancy tests • diagnosis of disease • measuring and monitoring • research • treating disease |
| How are monoclonal antibodies used in pregnancy tests? |
• the hormone human chorionic gonadotropin (HCG) is made in the early stages of pregnancy • tiny amounts of the hormone HCG is passed out in the urine • monoclonal antibodies bind to the hormone HCG • the binding causes a colour change indicating a positive result |
| How are diseases diagnosed with monoclonal antibodies? | the monoclonal antibodies are made to bind to specific antigens found on pathogens or on blood clots or on cancer cells |
| Name a disease that is detected using monoclonal antibodies. | prostrate cancer |
| How are monoclonal antibodies used to test for prostrate cancer? | monoclonal antibodies bind to prostate-specific antigens in the blood |
| How are monoclonal antibodies used in measuring and monitoring? | they are used to measure or monitor the levels of hormones and other chemicals in the blood |
| What is measured and monitored using monoclonal antibodies? |
• screening donated blood for HIV infection • detecting illegal drugs used by athletes • detecting syphilis |
| How are monoclonal antibodies used in research? |
• they are used to locate or identify specific molecules in a cell or tissue • scientists produce monoclonal antibodies linked to a molecule of a fluorescent dye • when the monoclonal antibodies bind to a molecule the build-up of fluorescence can be observed |
| Question | Answer |
|---|---|
| How are scientists hoping to use monoclonal antibodies to treat disease? | as they target a specific cell or chemical, it is hoped they can be used to treat very specific diseases |
| Name a group of diseases that scientists believe may be effectively treated with monoclonal antibodies. | many cancers that are not yet treatable may be able to be targeted using monoclonal antibodies |
| How many ways are there of treating cancers with monoclonal antibodies? | three |
| List the three ways of treating cancers with monoclonal antibodies. |
• direct use of monoclonal antibodies to trigger the immune system to recognise, attack, and destroy cancer cells • to block receptors on the surface of cancers and so stop the cells growing and dividing • to carry toxic drugs or radioactive substances for radiation therapy or chemicals that stop cells growing and dividing to attack the the cancer cells directly, without harming other cells in the body |
| What are the advantages of monoclonal antibodies? |
• they only bind to specific diseased or damaged cells that need treatment • the specificity of monoclonal antibodies means that they could be used to treat a wide range of conditions |
| Explain why it is an advantage that monoclonal antibodies only bind to specific diseased or damaged cells that need treatment. |
• conventional drugs are carried around the body in the blood and can damage healthy cells, sometimes very seriously • while radiotherapy in cancer treatment is targeted at the part of the body affected by the tumour, it affects healthy cells in or very near the area • by contrast, as monoclonal antibodies bind to specific cells, all other cells are unaffected |
| What has held back the use of monoclonal antibodies in the treatment of disease? | there were many more side-effects than expected |
| Why were there more side effects than expected with monoclonal antibodies? |
• the use of only mouse cells in the creation of hybridoma cells • the monoclonal antibodies were mouse antibodies and triggered an immune response in humans |
| How are side-effects for monoclonal treatments being reduced? |
• the production of human-mouse hybrid cells • the use of fractions of antibodies to carry drugs to target cells |
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