Fighting Disease

Question 1

What are the two main types of pathogen?

Answer 1

Bacteria and Viruses

Question 2

What are bacteria?

Answer 2

Bacteria are small living cells which reproduce rapidly inside of the body.

Question 3

How do bacterium make you feel ill?

Answer 3

1. Damaging cells

2. Producing toxins

Question 4

What are viruses?

Answer 4

Viruses are not cells and are 1/100 the size of bacterium

Question 5

How do viruses make you feel ill?

Answer 5

They replicate themselves by invading your cells and using the cells machinery to produce many copies of themselves. The cell will then burst and new viruses are released. The cell damage is what makes you feel ill

Question 6

How do white blood cells fight against disease?

Answer 6

1. Consuming them - white blood cells engulf foreign cells and digest them.
2. Producing antibodies- white blood cells produce proteins called antibodies that are specific to the type of antigen on the pathogen- they are produced rapidly and carried around the body to kill all similar bacteria /viruses. If the person is infected with the same pathogen again the white blood cells will rapidly produce the antibodies to kill it. The person is naturally immune to that pathogen and won’t get ill.
3. Producing antitoxins- these counter toxins produced by the invading bacteria.

Question 7

What are vaccinations and how do they work?

Answer 7

Vaccinations prevent a disease from happening. They work by injecting a small amount of dead or inactive microorganisms which carry antigens, causing the white blood cells/ body to produce antibodies to attack them. If live microorganisms of that disease appear in the body post vaccination, the white blood cells can rapidly mass-produce antibodies to kill off the pathogen

Question 8

What happens if vaccinations wear off over time?

Answer 8

Booster injections are given to increase the levels of antibodies

Question 9

What are the pros of vaccinations?

Answer 9

1. Vaccinations control lots of infectious diseases that were once common
2. Big outbreaks of disease (epidemics) can be prevented if a large percentage of the population are vaccinated. People who aren’t vaccinated are unlikely to catch the disease as there are fewer people unable to pass it on

Question 10

What are the cons of vaccinations?

Answer 10

1. Vaccines don’t always work, they don’t guarantee immunity in some cases
2. They can sometimes give you a bad reaction to a vaccine (swelling, fever etc).

Question 11

What are the purpose of painkillers?

Answer 11

They are drugs that relieve pain but don’t actually tackle the cause of disease. They reduce the symptoms

Question 12

How do antibiotics work?

Answer 12

They kill or prevent the growth of bacteria causing the problem without damaging other body cells.

Question 13

What don’t antibiotics do?

Answer 13

They don’t destroy viruses.

Question 14

How can bacteria develop antibiotic resistance?

Answer 14

1. Bacteria can mutate- this mutation can cause them to be resistant to an antibiotic
2. If you have an infection, some of the bacteria might be resistant to antibiotics.
3. This means that when you treat the infection, only the non- resistant strains of bacteria will be killed.
4. The individual resistant bacteria will survive and reproduce, the population of resistant bacteria strains will increase
5. The resistant strain can cause serious infection that can’t be treated bf antibiotics.
6. To avoid this, it’s important for doctors to jot over prescribe antibiotics

Question 15

How can you test the action of antibiotics or disinfectants?

Answer 15

By growing cultures of microorganisms

Question 16

How are microorganisms grown?

Answer 16

Microorganisms are grown in a ‘culture medium’ (usually agar jelly) containing carbohydrates, minerals, proteins and vitimans they need to grow. Hot agar jelly is poured into shallow round plastic dishes called Petri dishes. When the jelly is cooled and set, inoculating loops are used to transfer microorganisms to the culture medium. The microorganisms then multiply. Paper discs are soaked in different types of antibiotics and placed on the jelly. Antibiotic resistant bacteria will continue to grow around them but non resistant will die

Question 17

Why must Petri dishes have a lid ?

Answer 17

To stop any microorganisms in the air contaminating the culture

Question 18

Why must the temperature be kept low in school labs?

Answer 18

Harmful pathogens aren’t likely to grow at a low temperature (25°C)

Question 19

Why are ‘superbugs’ becoming more common?

Answer 19

Antibiotic resistance is more common and it is hard to kill bacteria

Question 20

How can bacteria cause problems in the future?

Answer 20

• a new strain of bacteria could be antibiotic resistant, so current treatments would no longer clear an infection
• a new strain could be one that we’ve not encountered before. So nobody would be immune to it
• the new strain could spread rapidly and could cause an epidemic

Question 21

How can viruses cause problems in the future?

Answer 21

• viruses can mutate, changes in their DNA lead to them having different antigens
• a virus could evolve that is deadly and very infectious
• a flu pandemic could occur

Question 22

What is a pandemic?

Answer 22

When a disease spreads all over the world