treatment of disease

Question 1

outline the history of vaccinations

Answer 1

they were first developed by edward jenner in the 1700s when he developed the first small pox vaccine

Question 2

what are vaccines

Answer 2

they are suspensions of antigens that are intentionally put into the body to induce long term artificial active immunity
they allow B-cells to produce antibodies + memory cells
- this allows for a stronger secondary immune response if infection occurs

Question 3

what are the 2 types of vaccines

Answer 3

live attenuated and inactivated

Question 4

live attenuated vaccines
- what are they made of
- how do they work
- limitations
- benefits
- examples

Answer 4

• contain whole pathogens that are weakened
• these multiply slowly and allow the body to recognise the antigens + trigger an immune response + the creation of antibodies
• can be unsuitable for people who are immunocompromised
• produces a stronger + longer lasting immune response
  e.g. MMR vaccine

Question 5

live attenuated vaccines
- what are they made of
- how do they work
- limitations
- benefits
- examples

Answer 5

• contain whole pathogens that are killed / parts of pathogens e.g. antigens, harmless forms of toxins
• they cannot cause disease as pathogens are not living
• can cause mild side effects, do not trigger strong + long lasting immune responses, often require booster doses
• safe for those with weak immune systems
  e.g. polio vaccine = a whole pathogen / diphtheria = toxin vaccine

Question 6

how can vaccines stop disease

Answer 6

they prevent large scale spread of disease, often they are offered by the government as preventative measures against epidemics
e.g. the young are given vaccines for once harmful diseases, like measles

they also give long term / life long immunity

Question 7

34problems with vaccines

Answer 7

• some people have poor responses and may be unable to produce the antibodies e.g. if malnourished
• antigenic variation means vaccine may not trigger the same immune response / allow for immunity
• diseases caused by eukaryotes may have too many antigens making it too difficult to make effective vaccines that prompt immune system quickly enough e.g. malaria
• viruses can change their antigens by antigenic drift, antigenic shift, antigenic concealment, or crossbreeding between different strains of virus

Question 8

antigenic drift definition

Answer 8

small changes in antigens over time which can prevent the pathogens from being recognised

Question 9

antigenic shift definition

Answer 9

large changes in antigens which can prevent the pathogens from being recognised

Question 10

antigenic concealment definition

Answer 10

pathogens are able to coat their body in host proteins or hide in cells, therefore not able to be recognised

Question 11

herd immunity definition

Answer 11

when a population has a sufficiently large portion of vaccinated + immune individuals, which provides immunity for the entire population as it prevents the spread of disease

Question 12

why is herd immunity so beneficial

Answer 12

people who have weak immune systems, are children, or cannot be vaccinated can still be protected against the disease

Question 13

ring immunity definition

Answer 13

when people living or working near a vulnerable or infected person are vaccinated to prevent them from catching + transmitting disease, protecting others who aren’t immune

Question 14

what are 2 general challenges of eradicating disease through vaccines

Answer 14

• some pathogens operate in more complicated mechanisms, for which successful vaccines / treatments have not yet been developed
• some diseases that could be eradicated haven’t because vaccine rates are too low, this is most common in areas with unstable political situations or a lack of public health facilities

Question 15

why is drug discovery important

Answer 15

maintaining drug discovery and research allows scientists to keep up with increasing antibiotic resistant strains

Question 16

give 4 ways new drugs can be developed

Answer 16

• genome analysis to find candidate genes that could code for potential drugs
• identifying molecules that fit into drug targets
• modifying pre-existing drugs, using computer programming
• identification of useful compounds produced by organisms

Question 17

what is a limitation of drug discovery

Answer 17

drug development requires a lot of time + money, and drugs must pass several trials before approval

Question 18

synthetic biology definition

Answer 18

this is an area of research that aims to create new biological parts / systems or to redesign pre-existing ones - this requires the assembly of an entirely new genomes, which will operate in novel ways

Question 19

give an example of synthetic biology in drug development

Answer 19

artemisinin - a commercially produced anti malarial drug
- E.coli and yeast are completely genetically reprogrammed - through the process of synthetic biology - to produce the drug on a large scale

Question 20

how is personalised medicine different to most disease treatment methods

Answer 20

it involves the development of more targeted drugs to treat a variety of human diseases + the development of synthetic tissues - unlike the universal approach often applied to drug prescription for treatment

Question 21

how does personalised medicine work

Answer 21

information gathered from genome projects can be used to develop genomic medicine - this allows drs to prescribe the most effective drugs based on genomes, as between individuals there are differences in DNA base sequences
- this approach is especially useful in cancer medicines

Question 22

what is genetic screening

Answer 22

a form of personalised medicine, when genomes of individuals are examined and individuals with a high chance of developing specific diseases are identified and offered preventative measures

Question 23

give an example of a drug initially found in microorganisms

Answer 23

penicillin
- discovered by alexander flemming
- initially from fungi
- this is an antibiotic, so it is effective against bacterial infections

Question 24

antibiotics definition

Answer 24

chemical substances that inhibit or kill bacterial cells with little to no harm to human tissue / other organisms
- this is possible as they target prokaryotic features

Question 25

what are the 2 types of antibiotic + the difference between them

Answer 25

bactericidal - kill bacteria
bacteriostatic - inhibit growth

Question 26

what is a disadvantage of antibiotics

Answer 26

they can affect both pathogenic and mutualistic bacteria

Question 27

broad spectrum antibiotics definition

Answer 27

antibiotics acting on a wide range of bacteria
- what is usually prescribed

Question 28

narrow spectrum antibiotics definition

Answer 28

antibiotics acting on only a small number of bacteria
- this is only prescribed if a culture has been taken proving the need for it

Question 29

how has antibiotic resistance arisen

Answer 29

• there is genetic variation within bacteria - some may possess alleles that confer resistance to the effects of the antibiotic
• the use of antibiotics exerts a selection pressure that can result in these alleles becoming more frequent
• as bacteria reproduce much faster, the allele spreads much faster, and over many generations the whole population could be resistant

Question 30

antibiotic resistance definition

Answer 30

when bacteria possess alleles that prevents antibiotics from affecting them

Question 31

what is antibiotic resistance an example of

Answer 31

natrual selection

Question 32

penicillin as a case study for antibiotic resistance

Answer 32

some bacteria have grown resistant to penicillin as they have developed genes that code for an enzyme which breaks down penicillin

Question 33

give an example of a famous antibiotic resistance bacteria

Answer 33

MRSA - a strain of bacteria that has developed a powerful resistance to methicillin - usually it lives harmlessly on the skin but if it is able to enter the body it can cause serious disease

Question 34

what are 3 things making the antibiotic resistance problem worse

Answer 34

• overuse of antibiotics, they are being used / prescribed when not necessary
• large scale use of antibiotics in farming to prevent disease, even when animals are not sick
• patients failing to complete the full course of antibiotics

these result in decreasing effectiveness of antibiotics and increased incidences of antibiotic resistance

Question 35

give 9 ways to reduce the impact of antibiotic resistance

Answer 35

• tighter controls in countries where antibiotics are sold without prescriptions
• drs avoiding the overuse of antibiotics and ensuring they prescribe the correct antibiotic, perhaps by testing pathogen first
• antibiotics not being used in non serious infections that the immune system can clear up
• patients must finish the course, not keep unused antibiotics for future self medication
• only using antibiotics for bacterial infections
• use of broad spectrum antibiotics should be reduced, replaced with narrow spectrum as resistance is less likely to occur
• type of antibiotics prescribed for the same infection should be changed
• limit use of antibiotics in farming
• limit spread of infection through good hygiene and isolating infected patients