Disease 2

Question 1

What happens in vaccination?

Answer 1

1. A dead or inactive version of a pathogen is injected into the blood
2. Lymphocytes recognise that the antigens are foreign and produce antibodies against them
3. Memory cells are created which remain in the blood

Question 2

Why do some parents not want their children to become vaccinated?

Answer 2

A false rumour was spread in the 1990s that the MMR vaccine caused an increased risk of autism. It was disproved and there is no evidence linking vaccines to autism.
Following this rumour, numbers of deaths from measles and mumps increased sharply

Question 3

What types of pathogen can people be injected against?

Answer 3

Bacteria

Viruses

Question 4

What are the benefits of vaccination?

Answer 4

• Prevents a person developing a serious illness or dying
• Can eradicate a disease e.g. smallpox
• Protects a population from the spread of a disease

Question 5

What are the weaknesses of vaccinations?

Answer 5

• Some people may suffer side effects and have allergic reactions
• Viruses mutate regularly so the vaccine may have to be adapted

Question 6

What are antibiotics?

Answer 6

Medicines used to destroy bacteria

Question 7

How do antibiotics work?

Answer 7

They destroy the cell walls of bacteria so they can’t divide and eventually burst and die

Question 8

Why do antibiotics not kill viruses?

Answer 8

Viruses stay inside host cells and are not themselves living cells

Question 9

How does antibiotic resistance happen?

Answer 9

Bacteria can evolve and mutate to become resilient to antibiotics

Question 10

How can we stop antibiotic resistance?

Answer 10

• Doctors should only prescribe antibiotics if they are needed and not for minor illnesses
• Doctors should vary the type of antibiotic prescribed as much as possible
• Patients should continue using the antibiotic until all bacteria are killed

Question 11

Why is MRSA a problem?

Answer 11

It is a bacteria resistant to many antibiotics which is evolving via natural selection faster than we can make new antibiotics to destroy it

Question 12

What control measures are used in hospitals against MRSA?

Answer 12

• Patients entering the hospital are screened for MRSA
• Hand washing and hand sanitising
• Stringent hygiene measures when dealing with open wounds

Question 13

What difference is there between how drugs were made in the past and how they are made now?

Answer 13

In the past, most drugs were extracted from plants and microorganisms e.g. aspirin comes from willow trees + penicillin comes from Penicillium mould

Nowadays, most drugs are synthesised by chemists in the pharmaceutical industry, but ingredients for these may chemicals from plants

Question 14

What are the types of drugs produced?

Answer 14

Painkillers
Antibiotics
Antiviral drugs

Question 15

Why do drugs need to be tested first?

Answer 15

To ensure they are safe and work properly and check if there are any serious side effects

Question 16

What criteria are drugs tested on?

Answer 16

Efficacy - Does the drug work?
Toxicity - Is the drug safe?
Dose - How much of the drug is needed?

Question 17

What are the two stages of drug testing?

Answer 17

1. Preclinical testing
   - Testing on human cells grown in a laboratory
   - Testing on animals
   - Testing on healthy human volunteers
   Low doses of the drug are initially used
2. Clinical testing
   - Testing on small groups of patients affected by the condition the drug is targeting

Question 18

What is a placebo?

Answer 18

A fake drug that has no effect on the body given to a control group in human drug trials (the other group receives the actual drug being tested)

This is to show that results are due to the effects of the drug and not the psychological expectations of the individual

Question 19

What are the two most common types of drug trials?

Answer 19

Blind trials:
Volunteers do not know which group they are in and neither do the researchers
Double blind trials:
Neither the volunteers nor the researchers know which group is which which removes chance of bias and makes the results more reliable

Question 20

What are monoclonal antibodies?

Answer 20

Identical copies of one type of antibody

Question 21

How are monoclonal antibodies produced?

Answer 21

1. An antigen is injected into a mouse
2. The mouse produces lymphocytes which produce antibodies specific to the antigen
3. Lymphocytes are removed during a small operation and fused with myeloma cells (tumour cells) to form hybridoma cells which divide indefinitely
4. Hybridoma cells divide and produce millions of monoclonal antibodies specific to the original antigen
5. Antibodies are extracted by centrifugation, filtration, and chromatography

Question 22

Why are lymphocytes fused with tumour cells?

Answer 22

Tumour cells divide extremely fast, but don’t contain antibodies.
Lymphocytes contain antibodies, but don’t divide as fast.
Merging them together produces a hybridoma cell with both of these qualities

Question 23

How can monoclonal antibodies be used to test for disease?

Answer 23

They can be attached to dyes that glow fluorescent under UV light to see which parts of the body contain particular molecules.
It not only tests if an infection is present, but also the extent of the infection due to how fluorescent the area is.

Question 24

How can monoclonal antibodies be used for tissue typing?

Answer 24

If an organ is a good tissue match for the recipient, their antigens on their cells must be similar so the immune system is less likely tor recognise the object as foreign.

Monoclonal antibodies can bind to the recipient’s white blood cells that produce antibodies against the new organ and inactivate them which reduces chance of infection

Question 25

How can monoclonal antibodies be used to treat cancer?

Answer 25

Monoclonal antibodies can be made to locate certain cells in the body and bind to them, including cancer cells.
If we attach anti-cancer drugs to the antibody, they will deliver the drugs directly to the tumour.
This is an effective treatment as antibodies don’t damage any other body cells in the process unlike chemotherapy and radiotherapy

Question 26

How can monoclonal antibodies be used in pregnancy tests?

Answer 26

When women are pregnant they produce a hormone that they do not have when not pregnant.
Antibodies in pregnancy tests are stuck to blue beads which, when the hormone is present in urine, travel down the test and display a positive result