1 Infection & Response 2

Question 1

Explain how contaminated food and water lead to the spread of pathogens?

Answer 1

Uncooked food or water contaminated with sewage can transfer pathogens like salmonella or cholera

Question 2

Explain how a break in the skin can lead to the spreading of pathogens?

Answer 2

The skin is the largest organ in the body and one of its main functions is to act as a barrier to prevent pathogens from entering the body
Cuts, burns, needle punctures and insect bites can allow pathogens to gain access

Question 3

Explain how droplet infection works?

Answer 3

Tiny droplets of liquid containing pathogens are expelled when you cough, sneeze or just talk

Question 4

List the first 2 defensive mechanism?

Answer 4

1. The skin acts as a barrier to stop pathogens from entering the body
2. If it’s cut, scabs form to prevent pathogens from entering the wound

Question 5

List the 3-4th defensive mechanism

Answer 5

3. The lungs contains sticky mucus which traps pathogens invading the breathing tubes, which can then be moved out & swallowed. The acid in the stomach destroys most of the pathogens that you swallow
4. The white blood cells form part of your immune system, should the pathogens get into the body. They cab defend you in 3 main ways

Question 6

What are the 3 ways white blood cells defend you if a pathogen gets into your body?

Answer 6

1. Ingesting microorganisms by phagocytosis, then destroying them with chemicals and enzymes within the cell
2. They can produce antibodies specific to each pathogens. These bind to the bacteria or virus and destroy it. Once you’ve made the antibody you can make it again quicker to stop you getting sick again
3. They also produce antitoxins which bind to & neutralise the toxins released by pathogens

Question 7

What do vaccinations do?

Answer 7

Also known as immunisation are designed to trigger the body’s own immune system, without causing the disease it’s self

Question 8

How do vaccines work?

Answer 8

1. Vaccines contain dead or inactive forms of the pathogen
2. They have proteins on their surface called antigens thar trigger the immune response
3. The white blood cells recognise these antigens and are triggered to produce antibodies
4. The white blood cells then remain your body as memory cells
5. If you then meet the pathogen in real life, the immune cells can very quickly produce the right antibodies again
6. This allows you to destroy the pathogen before it can cause harm

Question 9

What are the Advantages of vaccines?

Answer 9

• they have greatly reduced the occurrence of numerous infectious diseases, saving countless of lives
• if enough of the population is vaccinated, herd immunity prevents it from spreading so it eventually dies out

Question 10

How does herd immunity work?

Answer 10

If one person contracts a disease, there are a sufficient number of vaccinated people in the population that it’s unlikely that an infected person will be able to pass it to anyone not immune

Question 11

What do antibodies do?

Answer 11

They’re Produced by white hollow cells to destroy particular becterai or viruses

Question 12

What do antibiotics do?

Answer 12

Drugs that kill infective bacteria inside the body

Question 13

What do antitoxins do?

Answer 13

Counteract poisons released by pathogens

Question 14

What does antiseptic do?

Answer 14

Kill ineffective bacteria outside the body

Question 15

What do antibiotics not treat?

Answer 15

Viral diseases

Question 16

What can bacterial tissues so?

Answer 16

Makes us feel ill and damage tissues

Question 17

What does immunity mean?

Answer 17

Immunity allows a person to produce antibodies quickly to prevent infection

Question 18

In the 18th century, surgeons didn’t think wear special clothing or wash their hands before operations. Many of their patients does from infections. Why did they die?

Answer 18

Because the doctors where transmitting bacteria from their hands

Question 19

There have been no cases of polio in the uk for many years, but children are still vaccinated with it? Why?

Answer 19

• in case it returns
• people from other countries may still carry it
• if they go abroad they could be exposed to it
• herd immunity

Question 20

Name 1 type of medicine which helps to relieve the symptoms of infectious diseases?

Answer 20

Painkiller

Question 21

Name 1 medicine that kills bacteria?

Answer 21

(Antibiotics) ampicillin

Question 22

What’s measles?

Answer 22

• it’s a viral disease spread by droplets from sneeze or cough
• develop a red skin rash and signs of fever
• can be fatal if there’s complications. Can sometimes lead to pneumonia or encephalitis (a brain infection)
• most people are vaccinated against it when they’re young

Question 23

What does TMA and what does it do?

Answer 23

• tobacco mosaic virus, is a virus that affects many species of plants eg. Tomatoes
• it causes a mosaic pattern on the leaves- done parts become discoloured
• this means the plant can’t carry out photosynthesis so the virus affects growth