Fighting Disease

Question 1

What are bacteria?

Answer 1

Bacteria are very small cells?

Question 2

What 2 ways do bacteria make you feel ill?

Answer 2

Bacteria can (a) damage cells and (b) produce toxins

Question 3

What is a virus?

Answer 3

A virus is the smallest of microorganisms and they replicate themselves.

Question 4

How does a virus work?

Answer 4

They replicate themselves by invading your cells and using the cells machinery to replicate themselves.

The cell then usually bursts releasing all the new virus.

The cell damage makes the person feel ill.

Question 5

How does your body’s defence system work?

Answer 5

1. Your skin, hairs and mucus (in your respiratory tract) stop a lot of nasties getting inside your body.
2. If you cut your body then small fragments of cells (called platelets) help blood clot quickly to seal wounds. If your body has low numbers of platelts then your blood will clot slower.
3. If something does get through into your body then your immun system kicks in and this is where your white blood cells kick in.

Question 6

How doe white blood cells work ?

Answer 6

1. They CONSUME (ie ENGULF and DIGEST) the microbes
2. They produce ANTIBODIES to kill the invading microbe
3. They produce ANTITOXINS which counteract the toxins produced by the invading bacteria

Question 7

Explain in more detail the process where white blood cells produce antibodies?

Answer 7

1. Every invading cell has unique molecules called ANTIGENS on their surface
2. When white blood cells come accross a foreign ANTIGEN they don’t recognoise they produce PROTEINS called ANTIBODIES to kill the ANTIGENS.
3. The Antibodies are the produced rapidly and carried around the body to kill all SIMILAR bacteria or viruses
4. If the person is ever infected again with the same PATHOGEN the white blood cells can produce much quicker the same antibodies ie the person is naturally immune to the pathogen

Question 8

If your white blood cells can protect against invading pathogens why do you still feel ill?

Answer 8

Because it takes a while for this process to happen and during these days the micoorogasim is winning and this makes you feel ill.

Question 9

How does a vaccination work?

Answer 9

You are injected with DEAD or INACTIVE microorgasims. these carry ANTIGENS whcih cause the white blood cells to produce ANTIBODIES to attack them even though the micorgasims are dead or inactive and therefore harmless.

By doing this your white blood cells learn what ANTIBODIES are required for the micoorgasim so if you are ever infected with live micorgasims your body can react very quickly.

Question 10

Once vaccinated are you protected forever?

Answer 10

No, some vacinations wear off after time.

Question 11

What are the advantages of vaccination?

Answer 11

1. They help control lots of infectious diseases that were once common in the UK.
2. Epidemics can be prevented if a large percentage of the population are vaccinated.

Question 12

What are the disadvanates of vaccination?

Answer 12

1. Vaccinations don’t always work.

2. You can sometimes have a bad reaction to the vaccination.

Question 13

Do drugs cure the problem (disease)?

Answer 13

Not always - it depends on the disease and the drug. some drugs relieve the symptoms and other drugs cure the problem.

Question 14

Give some examples of drugs that relieve the syptoms but do not cure the problem

Answer 14

1. Painkillers.
2. Cough mixture
3. Cold remedies such as Lemsip

Question 15

Give an example of a drug that can cure the problem

Answer 15

Antibiotics (eg penicillen) kill (or prevent the growth) of the bacteria causing the problem without killing your own body cells.

You need to pick the right antibiotic to kill the right bacteria and if you don’t then they will not work.

Question 16

What drug can kill a virus?

Answer 16

There is not a drug (such as antibiotic) that can kill a virus. This is because the virus uses your own body cells to replicate itself so the only way to kill it is by killing your own body cells which is not a good idea.

Question 17

Can bacteria become resistant to antibiotics

Answer 17

Yes, bacteria can mutate causing them to be resistant to an antibiotic which means that the NEW STRAIN of bacteria will not be killed.

Question 18

How do you slow down the rate of resistant strain of bacteria to antibiotics?

Answer 18

Doctors should avoid over -prescribing antibiotics and they should only be prescribed for serious matters (ie not a sore throat).

Question 19

How can you investigate and test the action of antibiotics

Answer 19

You can test them by growing cultures of microorgagisms in an agar jelly in a Petri dish.

Question 20

Explain the testing process for antibiotics in a petri dish

Answer 20

1. Microorganisms are grown in a “culture medium”.
2. A “culture medium” is usually a petri dish using agar jelly which contains the carbohydrates, minerals, proteins and vitamins they need to grow.
3. You poor hot agar jelly into dish and let is cool and set.
4. When jelly is cooled, use INOCULATING LOOPS to transfer microorgasims to the culture medium and let them multiply
5. Paper discs are soaked in different types of antibiotics and placed on the jelly. Antibiotic resistant bacteria will grow around them but other bacteria won’t.
6. All equipment must be sterlised.
7. Petri dish must have a lid taped on to prevent other bacteria from the air contaminating the jelly
8. In lab cultures kept at 25 c

Question 21

How did Semmelweis cut deaths ?

Answer 21

He cut death in childbirth from 12% to 2% by telling doctors to wash their hands with antiseptic solution.

The antispectic solution killed bacteria (he didn’y know this as existance of bacteria was not known at time).

As a result of the lack of knowedge of bacteria, doctors stopped washing their hands and deathrates went up again.

As such basic hygiene is very important in controlling disease

Question 22

What is a superbug?

Answer 22

A bacteria that is resistant to most known antibiotics (eg MRSA)

Question 23

What is a problem with the overuse of antibiotics?

Answer 23

Bacteria can evolve and a new STRAIN of bacteria can develop resistance to an antibiotic.

Question 24

What problems do virus present to the population?

Answer 24

Viruses also tend to mutate ofte making it hard to develop a vaccine against them.

Some viruses develop very quickly and are deadly and very infections (bird flu).

As such to stop the spread (where vacines don’t work) you would need to place restructions on how people travel and increase hygiene (wash hands with antispetic soap a lot more).