B6- preventing and treating disease 💉

Question 1

How do vaccines work ? [5]

Answer 1

• vaccination involves introducing small quantities of dead or inactive forms of a pathogen into the body.
• [because the pathogen is dead or inactive, it cannot lead to the disease in the patient.]
• the white blood cells are now stimulated to produce antibodies, against the dead or inactive pathogen.
• and at the same time, the white blood cell divides by mitosis, to produce lots of copies of itself- these white blood cells can stay in the body for decades.
• now if the same pathogen enters the body, [even years later], the white blood cells can produce correct antibodies quickly, preventing infection.

Question 2

What can you tell me about a graph about: amount of antibody and time.

Answer 2

• when the real pathogen invades, the antibody production rises very quickly and to a very high level- this is because of the vaccination.

Question 3

What is herd immunity ?

Answer 3

• herd immunity is vaccinating a large number of people/ the population against pathogens, so if people don’t get vaccinated, this will protect people who are unvaccinated.
• This is because, the unvaccinated person can’t catch the disease, since no-one around them can pass the pathogen on.

Question 4

Explain why, if a large proportion of the population is vaccinated, the spread of the pathogen is reduced

Answer 4

• if a large proportion of the population is vaccinated, the spread of the pathogen is reduced because:
• When the majority of a population is vaccinated against a pathogen, it breaks the pathogen’s chain of infection hence.
• meaning the spread of the pathogen is reduced, therefore it is unable to pass from person to person.

Question 5

In the 1940s, what was the first antibiotic to be discovered ?

Answer 5

• In the 1940s, penicillin was the first antibiotic to be discovered by Alexander Fleming
• and it helps to cure bacterial diseases, by killing infective bacteria in the body.

Question 6

What is antibiotic resistance ?

Answer 6

• several years ago, doctors discovered that certain antibiotics were no longer effective against certain bacteria.
• this is because antibiotics have been overused, therefore the bacteria had evolved, so that they were no longer killed by the antibiotic.

Question 7

Why is antibiotic resistance a severe problem ?

Answer 7

• antibiotic resistance a severe problem, since in the future, it’s possible bacterial diseases will become very difficult to treat.

Question 8

How are doctors careful, when prescribing antibiotics?

Answer 8

• doctors are careful, when prescribing antibiotics since they always use specific antibiotics, to treat specific bacteria.

Question 9

Why won’t doctors prescribe antibiotics for conditions that may be caused by viral pathogens ?

Answer 9

• doctors won’t prescribe antibiotics for conditions that may be caused by viral pathogens, because antibiotics can’t kill viruses [since they live in reproduce inside host/human cells].
• Fo example, certain types of sore throat.

Question 10

What are painkillers ?

Answer 10

• painkillers, treat the symptoms of the disease by relieving the pain, and is a drug that doctors will prescribe.
• ; medicines such as painkillers don’t kill pathogens and treat the disease itself. They only treat the symptoms

Question 11

Why is it difficult to develop drugs that kill viruses, without damaging the body’s tissues ?

Answer 11

• it’s difficult to develop drugs that kill viruses, without damaging the body’s tissues because viruses live and reproduce inside human cells.

Question 12

What are antibiotics?

Answer 12

• Antibiotics are substances which kill or inhibit the growth of bacteria.
• and they are often produced by one type of microbe in order to kill other microbes.
• [For example, penicillin was extracted from the fungus and microbe penicillium]

Question 13

What plant was used to extract the heart drug, digitalis ?

Answer 13

• the plant foxglove, was used to extract the heart drug, digitalis.

Question 14

What was the painkiller aspirin, extracted from ?

Answer 14

• the painkiller aspirin, was extracted from willow trees.

Question 15

What are most new drugs synthesised by ?

Answer 15

• most new drugs synthesised by chemists, working for pharmaceutical companies.
• ; the starting point, is still often a chemical that is extracted from a plant.

Question 16

What does synthesised mean ?

Answer 16

• synthesised means, the production of chemical compounds by a reaction from simpler materials

Question 17

What do we need to test and trial drugs for ? [3]

Answer 17

• toxicity- whether it is safe for humans
• efficacy- whether the drug is effective, and treats the disease that we’re looking at.
• dosage- The most effective amount of drug needed to cure the disease.

Question 18

What are the stages of drug trials ? [4]

Answer 18

• 1) preclinical testing- it’s not done on humans, since the drug could be extremely toxic.
• and it’s instead carried out out cells, tissues and live animals.
• 2) clinical testing- this is carried out on humans, and very low doses are given to healthy volunteers- this is to check the drug is safe in humans.
• 3) If the drug is found to be safe, clinical testing contuines to find the optimal dose.

Question 19

What is the optimal dose [of a drug] ?

Answer 19

• the optimal dose, is the best dose to treat the disease, without the fewest side- effects.

Question 20

What is the optimal dose [of a drug] ?

Answer 20

• the optimal dose, is the best dose to treat the disease, without the fewest side- effects.

Question 21

What is a placebo ?

Answer 21

• a placebo, is a tablet or injection with no active drug in it.
• and some patients will get better if given a placebo, because they think they’re being treated, so they believe they’re going to get better.

Question 22

What is a double-blind trial ?

Answer 22

• in a double blind trial, the test group receive the active drug.
• and the placebo [control] group, are given a dummy drug [a placebo], which looks like the test drug; it has no active ingredient.

Question 23

What is a feature about a double- blind trial ?

Answer 23

• in a double-blind trial, neither the patients nor the doctors know which people are receiving the active drug and which are receiving the placebo.
• This is to stop bias, in case the doctors pay closer attention, to people receiving the active drug.

Question 24

What is Phase I of clinical testing in drug trials ?

Answer 24

• Phase I Human trials testing on volunteers:
• The (very few) chemicals that pass the animal testing stage move on to the first human tests.
• These are done on healthy people
• and are often students who get paid a small amount of money for volunteering. This stage checks the safety of the drug and looks for side effects.

Question 25

What is Phase II of clinical testing in drug trials ?

Answer 25

• Phase II Testing on patients: The first ill people to get the drug are the Phase II volunteers
• and this is where scientists can really begin to see if the drug will be safe and effective.

Question 26

What is Phase III of clinical testing in drug trials ? [4]

Answer 26

• Phase III Final tests and licensing: If all goes well with phase II the trials move to phase III.
• Many more people are given the new drug. Some of the people in the phase III trial will be given dummy treatment [placebos] so that doctors can compare the effect of the drug with already available medicines or nothing at all.
• By the end of a successful phase III the drug company submits its research to government bodies to ask for a licence to sell the drug.

Question 27

What is Phase IV of drug trials ?

Answer 27

• phase IV trials:
  doctors report on any side effects suffered by their patients, and
  continue as long as the medicine is used.
• Phase IV trials can
  involve hundreds of thousands of people.

Question 28

Explain why the results of drug trials are published in peer-reviewed journals.

Answer 28

• the results of drug trials are published in peer-reviewed journals [before there published to the public] because, it helps to prevent and detect false claims.