preventing and treating diseases

Question 1

how do vaccinations work

Answer 1

1) small amounts of dead or inactive pathogens of the disease are injected into the body
2) these carry antigens which cause your body to produce antibodies to attack them even though the pathogen is harmless
3) this causes the person to develop immunity as if the same pathogen re-enters the body your white blood cells will respond quickly as it has made the same antibodies as before

Question 2

pros of vaccinations

Answer 2

• help control lots of communicable diseases that were once common in the UK
• epidemics can be prevented if a large percentage of the population is vaccinated as it makes people that are not vaccinated unlikely to catch the disease as there are fewer people to carry it and pass it on, but if there is a significant number of people that arent vaccinated the disease can spread quickly and lots of people will be ill at the same time

Question 3

cons of vaccination

Answer 3

• vaccinations dont always work
• you can sometimes have a bad reaction to a vaccine

Question 4

what do painkillers do

Answer 4

they relieve pain by not tackling the cause of the disease or kill the pathogen, just relieving the symptoms

Question 5

what do antibiotics do

Answer 5

• they kill the bacteria causing the problem without killing your own body cells, different antibiotics kill different types of bacteria

Question 6

why is it difficult to develop drugs that destroy viruses

Answer 6

as viruses reproduce using your own body cells which makes it very difficult to develop drugs that destroy just the virus without killing the body cells

Question 7

what happens when a bacteria becomes resistant to an antibiotic

Answer 7

bacteria can mutate and become resistant to the antibiotic, this means that when you treat a bacterial infection only the non-resistant strains of bacteria will be killed, so the individual resistant bacteria will survive and reproduce and the population of the resistant strain will increase, then the resistant strain could the cause serious infections that cannot be treated with antibiotics

Question 8

cons of antibiotics

Answer 8

• cant kill viruses
• bacteria can become resistant
• have to take regularly to finish whole course

Question 9

how do doctors slow the rate of the development of resistant strains

Answer 9

• by avoiding to overprescribe antibiotics
• encouraging the patient to finish the whole course of the antibiotics

Question 10

what is MRSA

Answer 10

a strain of bacteria that is resistant to the powerful antibiotic meticillin

Question 11

examples of drugs extracted from plants

Answer 11

• aspirin - used as a painkiller and to lower fevers - found in willow bark
• digitalis - used to treat heart conditions - found in foxgloves

Question 12

examples of drugs extracted from microorganisms

Answer 12

• penicillin - found when alexander fleming noticed that one of his Petri dishes of bacteria had mould on it and the area around the mould was free of bacteria and found that the mould in the dish was producing a substance that killed the bacteria, this substance was known as penicillin

Question 13

what happens in the 1st stage of developing drugs

Answer 13

1) chemicals are screened
2) in preclinical testing the drug is then testested on human cells and tissues however this does not tell us the affect on the whole body system

Question 14

what happens in the 2nd stage of developing drugs

Answer 14

1) the next step of preclinical testing is to test the drug on live animals, this is to test the efficiency, find out its toxicity and the dosage
2) however some people think its cruel to test on animals but others believe its the safest way to make sure the drug isnt dangerous before its given to humans

Question 15

what happens in the 3rd stage of developing drugs

Answer 15

1) if the drug passes the test on animals it is tested on healthy human volunteers in clinical testing, this makes sure it doesn’t have any harmful side effects when the body is working normally
2) at the start of the trial a very low dosage of the drug is given and this dosage gradually increases
3) if the test on healthy volunteers are good the drugs are tested on a small number of people who have the disease
4) to test how well the drug works patients under a double-blind test as the doctor nor the patient knows whether they are given the placebo or drug, are put into two groups one is given a new drug whilst the other is given a placebo, this is so the doctor can see the difference the drug makes
5) double trial tests allow doctors to analyse and monitor the results without influencing and altering them with their knowledge
6) the results of the drug testing and drug trials arnt published until they have been through peer review to help with false claims

Question 16

what is it meant by the efficiency of a drug

Answer 16

• whether the drug work and if it produces the effect its meant to

Question 17

what is it meant by the toxicity of a drug

Answer 17

how harmful it is

Question 18

what is it meant by the dosage of a drug

Answer 18

the concentration that it should be given in and how often it should be taken

Question 19

how are monoclonal antibodies made

Answer 19

1) a mouse is injected with the chosen antigen
2) this causes the b lyphocytes a special type of white blood cell to start producing antibodies
3) the b lymphocytes are taken from the mouse and are fused with a tumour cell to create a hybridoma, this allows the white blood cells to divide rapidly to produce lots of the same antibodies, monoclonal antibodies
4) the antibodies is then collected and purified

Question 20

why are monoclonal antibodies useful

Answer 20

the will only bind to a certain molecule, this means that you can use them to target a specific cell or chemical in your body

Question 21

how are monoclonal antibodies used in pregnancy tests

Answer 21

1) the women urinate onto the test strip, which contains monoclonal antibodies that are specific to HCG with blue beads attached to it ( a hormone that is found in the urine of women only when they are pregnant)
2) when the beads and the antibodies are attached they are mobile and free to move around
3) if you are pregnant- the hormones bind to the antibodies containing the blue beads, and the urine then moves up the stick, carrying the hormones and the beads, it then binds to the immobile antibodies on the strip, so the blue beads get stuck on the strip turning it blue, indicating a positive result
4) if you are not pregnant the urine still moves up the stick, carrying the blue beads, but there’s nothing to stick the blue beads onto the test strip so it doesn’t go blue
5) in some pregnancy tests whether if a women is pregnant or not a second line appears known as the control line, here immobile antibodies bind to the excess mobile antibodies that didn’t pick up HCG and continued travelling up the strip, this shows that the test is working

Question 22

what are monoclonal antibodies used for

Answer 22

• in pregnancy tests monoclonal antibodies bind to the HCG found in early pregnancy
• in labs it measures the levels of hormones and other chemicals in the blood to detect pathogens
• in research its used to locate or identify molecules in cells or tissue by binding them with fluorescent dye
• to treat diseases

Question 23

how do monoclonal antibodies treat disease

Answer 23

different cells in the body have different antigens monoclonal antibodies can bind with specific cells in the body to help treat them

Question 24

how do monoclonal antibodies treat disease

Answer 24

different cells in the body have different antigens monoclonal antibodies can bind with specific cells in the body to help treat them

Question 25

how do monoclonal antibodies help treat cancer cells

Answer 25

• cancer cells have antigens on their cell membranes that aren’t found on normal body cells, called tumour markers
• in the lab you can make monoclonal antibodies that will bind with these markers, an anti-cancer drug is then attached to the monoclonal antibody which stops cancer cells from growing and dividing
• the antibodies are given to the patient through a drip and target the cancer cells as they only bind to tumour markers
• the drug kills the cancer cells but doesn’t kill any normal body cells near the tumour

Question 26

how can monoclonal antibodies be used in labs and research to find specific substances

Answer 26

1) the monoclonal antibodies are made to bind to the specific molecule you are looking for
2) the antibodies are attached to a fluorescent dye
3) if the molecules are present in the sample your analysing the monoclonal antibody will attach to them and they can be detected using the dye

Question 27

cons of monoclonal antibodies

Answer 27

• can cause side effects, meaning they are not widely used as treatments

Question 28

pros of monoclonal antibodies

Answer 28

• can be used as cancer treatment without affecting normal body cells as they target specific cells, this means that the side effects of antibody based drugs are lower than for standard chemotherapy or radiotherapy