protecting ourselves against infectious diseases

Question 2

what are the microorganisms that cause infectious disease

Answer 2

pathogens

Question 3

what may bacteria do inside the body

Answer 3

bacteria may reproduce rapidly inside the body and produce poisons (toxins) that make us feel ill

Question 4

what may viruses do inside the body

Answer 4

viruses may reproduce rapidly inside the body. viruses live and reproduce inside cells, causing damage

Question 5

how do white blood cells help to defend against pathogens

Answer 5

-ingesting pathogens -producing antibodies, which destroy particular bacteria or viruses -producing antitoxins, which counteract the toxins released by the pathogens

Question 6

what leads to immunity from a pathogen

Answer 6

the immune system of the body produces specific antibodies to kill a particular pathogen

Question 7

what greatly reduces the spread of a pathogen

Answer 7

if a large proportion of the population is immune to the pathogen

Question 8

how can people be immunised against a disease

Answer 8

by introducing small quantities of dead or inactive forms of the pathogen into the body (vaccination)

Question 9

how do vaccines work

Answer 9

vaccines stimulate the white blood cells to produce antibodies that destroy the pathogen. this makes the person immune to future infections by the microorganism, because the body can respond by rapidly making the correct antibody, in the same way as if the person had previously had the disease

Question 10

what does the MMR vaccine protect against

Answer 10

the MMR vaccine is used to protect children against measles, mumps and rubella

Question 11

for vaccinations argument

Answer 11

Vaccines stop individuals becoming ill. If enough people are vaccinated, vaccinations can also stop pathogens infecting whole populations. This is called herd immunity. The chance of falling seriously ill or dying from the disease may be far greater than the chance of experiencing a serious side-effect. using a vaccine may be much cheaper than treating a very ill person.

Question 12

against vaccines argument

Answer 12

-some people suffer from a mild reaction to the vaccine. -in recent years there has been much controversy surrounding the MMR vaccine. Some people used to think the vaccine could cause autism in children. They decided not to risk letting their child have the vaccine and just hoped they would not catch measles, mumps or rubella.

Question 13

what do some medicines such as painkillers do

Answer 13

they help to relieve the symptoms of infectious disease, but do not kill the pathogens

Question 14

what are antibiotics and give an example

Answer 14

antibiotics, such as penicillin, are medicines that help to cure bacterial disease by killing infective bacteria inside the body

Question 15

what is important about the use of antibiotics

Answer 15

it is important that specific bacteria should be treated by specific antibiotics

Question 16

what can antibiotics not kill

Answer 16

viral pathogens

Question 17

whats difficult about developing drugs that kill viruses

Answer 17

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

Question 18

how is a new resistant strain made

Answer 18

mutations of pathogens produce new strains. antibiotics kill individual pathogens of the non-resistant strain but individual pathogens survive and reproduce, so the population of the resistant strain rises. antibiotics and vaccinations may no longer be effective against a new resistant strain of the pathogen. the new strain will then spread rapidly because people are not immune to it and there is no effective treatment

Question 19

what has increased the rate of development of antibiotic-resistant strains of bacteria

Answer 19

overuse and inappropriate use of antibiotics

Question 20

whats an example of one of the many strains of bacteria that has developed resistance to antibiotics

Answer 20

MRSA

Question 21

what is done in order to slow down the rate of development of resistant strains

Answer 21

antibiotics are not currently used to treat non-serious infections such as mild throat infections

Question 22

what does the development of antibiotic-resistant strains mean for pharmaceuticals

Answer 22

it necessitates the development of new antibiotics

Question 23

what is required for investigating the action of disinfectants and antibiotics

Answer 23

uncontaminated cultures of microorganisms

Question 24

what needs to be done while using uncontaminated cultures of microorganisms to investigate the action of disinfectants and antibiotics

Answer 24

-petri dishes and culture media must be sterilised before use to kill unwanted microorganisms -inoculating loops used to transfer microorganisms to the media must be sterilised by passing them through a flame -the lid of the petri dish should be secured with adhesive tape to prevent microorganisms from the air contaminating the culture, and stored upside down to stop bacteria falling onto the agar surface

Question 25

what is the maximum temperature that cultures should be incubated at in school and college laboratories

Answer 25

25 degrees celcius

Question 26

why should cultures be incubated at a maximum temperature of 25 degrees in school and college laboratories

Answer 26

it greatly reduces the likelihood of the growth of pathogens that might be harmful to humans

Question 27

how can the temperature for incubating cultures change in industrial conditions

Answer 27

higher temperatures can produce more rapid growth