B1.1 Keeping Healthy (Part 2/2 B1.1.2 Immune System) Flashcards Preview

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Flashcards in B1.1 Keeping Healthy (Part 2/2 B1.1.2 Immune System) Deck (24)
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1
Q

Define ‘pathogen’

A

Disease causing microbe

2
Q

Name the 4 types of microbe

A
  • Bacteria
  • Viruses
  • Fungi
  • Protoctista
3
Q

What are the 3 natural barriers your body has to pathogens?

A
  • Skin: the platelets help blood clot quickly to seal wounds and cuts
  • Hairs and mucus in the respiratory tract trap pathogens which are swallowed into gut
  • Stomach acid
4
Q

Describe 3 ways white blood cells protect against pathogens.

A
  • Ingesting them
  • Producing antitoxins which counteract the toxins produced by bacteria
  • Producing antibodies
5
Q

How does immunity develop?

A
  • When white blood cells come across a foreign antigen, they produce specific antibodies that lock onto a specific one
  • They are produced rapidly and carried around the body
  • Once white blood cells have recognised which type to produce they can do so much faster without you feeling so many symptoms
6
Q

How do bacteria make us feel ill?

A
  • Damaging cells

- Producing toxins

7
Q

How do viruses make us feel ill?

A
  • They replicate themselves by invading cells and using them to reproduce
  • The cell then bursts, releasing new viruses
  • This cell damage makes you feel ill
8
Q

How are microbes grown in the lab?

A
  • Sterilise the Petri Dish and nutrient agar for use by heating it in the autoclave.
  • Sterilise the inoculation loop by passing it through a flame and then allowing to cool.
  • Dip the sterilised loop in the microbe suspension and make zigzag streaks across the agar surface (to get an even spread of microbes across the surface)
  • Close the lid as quickly as possible and seal with adhesive tape. (prevents contamination from air)
  • Incubate the dishes at 25C degrees to allow microbes to grow
  • After observation, resterilise the dishes complete with their cultures by heating to 100 degrees, then throw away.
9
Q

How did Semmelweis change the behavior of doctors?

A
  • He saw many women were dying from puerperal fever
  • He believed doctors were spreading the disease through unwashed hands from cutting up corpses to delivering babies
  • Whilst he was at hospital, he made the doctors there use antiseptics and deaths decreased.
  • But his methods were dropped once he left hospital, so deaths increased
10
Q

What is the process of vaccination?

A
  • Doctor’s inject a weakened/dead microbe into your body
  • White blood cells identify and make antibodies in reaction to the foreign antigen. These antibodies remain in the blood (as if the person had the disease before)
  • If the real microbes attack, the body can rapidly mass-produce some antibodies to kill them off
  • Some “wear off” overtime, needing booster vaccines
11
Q

How do strains of bacteria become resistant?

A

1) Bacteria can genetically mutate, some mutations cause them to become resistant to antibiotics
2) So in treating an infection, only the non-resistant strains are killed
3) The resistant bacteria will survive and reproduce and the population of the resistant strain will increase, meaning more bacteria are untreatable by antibiotics

12
Q

Give an example of a bacteria resistant to antibiotics

A

MRSA

13
Q

What’s the difference between painkillers and antibiotics?

A

Painkillers help to relieve the pain of symptoms, whereas antibiotics kill the pathogens.

14
Q

Give one example of an antibiotic and who invented it.

A

Penicillin - Alexander Fleming

15
Q

What reduces the spread of the pathogen across a population?

A

If a large proportion of the population is immune to a pathogen so that even those unvaccinated are less likely to pick up the disease because there are fewer to pass it on.

16
Q

Why are antibiotics used only to kill bacteria?

A

It is hard to develop drugs which kill viruses without damaging body cells, as they live and reproduce inside it

17
Q

Define ‘epidemic’

A

A sudden outbreak of disease over a country.

18
Q

Define ‘pandemic’

A

A sudden outbreak of disease over the world.

19
Q

How is the rate of development of resistant strains of bacteria slowed down?

A

Antibiotics are not used to treat non-serious infections, such as mild throat infections

20
Q

What does the MMR vaccine protect against?

A
  • Measles
  • Mumps
  • Rubella
21
Q

Why are cultures incubated at a maximum temperature of 25 °C in school/college laboratories?

A

It greatly reduces the likelihood of growth of

pathogens that might be harmful to humans.

22
Q

Why are higher temperatures used in industrial conditions to incubate cultures?

A

Higher temperatures can produce more rapid growth, and in those conditions dangerous strains can grow without harm to anyone.

23
Q

What are the advantages of vaccines?

A
  • They had helped control diseases that were once common (e.g measles is controlled, smallpox no longer occurs)
  • Epidemics can be prevented if a large percentage is vaccinated
24
Q

What are the disadvantages of vaccines?

A
  • Side effects e.g swelling/fever

- Expensive