B6 Preventing and treating disease

Question 1

How do vaccinations work?

Answer 1

• Small amounts of dead or inactive pathogens are put into the body, often by injection
• The antigens in the vaccine stimulate the white blood cells into making antibodies
• The antibodies destroy the antigens without any risk of patient getting the disease
• Patient is now immune to future infections, because their body can now respond rapidly and make the correct antibody as if they had already had the disease

Question 2

What is the function of memory cells?

Answer 2

Recognises the same pathogen if it invades a second time, to produce a large number of antibodies in a short time

Question 3

Antibiotics

Answer 3

• Only work on bacteria
• Either kill bacteria or prevent the from reproducing
• Do not harm normal body cells
• May kill a wide range of bacteria or just a specific bacteria

Question 4

What are antibiotics?

Answer 4

Chemicals that kill or prevent reproduction of bacteria

Question 5

Why is it important not to overuse antibiotics?

Answer 5

To reduce antibiotic resistance

Question 6

Why is it important the be treated with the right antibiotic for a particular infection?

Answer 6

Specific antibiotics work against specific bacteria

Question 7

what are painkillers?

Answer 7

drugs that treat the symptoms of disease, but don’t kill the pathogens

Question 8

how to painkillers help against pathogens?

Answer 8

• Have no effect on the pathogen
• Help to alleviate the symptoms so the patient feels better but they still need to wait for their immune system to get rid of the pathogen
• Examples include paracetamol, aspirin, ibuprofen

Question 9

What do drugs need to be tested for?

Answer 9

1. Toxicity - is it going to cause harm
2. Efficacy - does it cure the disease or prevent the symptoms
3. Dosage - how much do patients need to get the required effects without it being dangerous, how does this vary between different age groups, genders etc

Question 10

describe how clinical trials work

Answer 10

preclinical trial: testing on animals, cells, tissues etc
phase 1: drug is tested on healthy volunteers at a low dose for toxicity
phase 2: drug is tested on patients with the disease; efficacy of drug is looked at
phase 3: drug is tested on a large number of people, with or without disease to test for dosage, double blind trial is done here
approval by regulatory bodies is needed
start prescribing drug
phase 4: monitoring long term effect of the drug

Question 11

What is a double-blind trial?

Answer 11

Neither the patient nor the doctor know who has been given the placebo or real drug. This helps prevent the doctor from being biased in their reporting of the effects of the drugs

Question 12

What is the purpose of a double-blind trial?

Answer 12

helps prevent the doctor from being biased in their reporting of the effects of the drugs

Question 13

What is herd immunity?

Answer 13

Large proportion of population is immune to a disease

Question 14

Which pathogen does antibiotics destroy?

Answer 14

Bacteria

Question 15

Why can’t antibiotics kill viruses?

Answer 15

Viruses reproduce inside cells, antibiotics cannot enter cells without damaging the cell

Question 16

How might an antibiotic be useless against a bacteria?

Answer 16

Antibiotic resistance

Question 17

What is a placebo?

Answer 17

A medicine that does not contain the active drug being tested

Question 18

What are monoclonal antibodies?

Answer 18

Proteins that target particular cells/chemicals

Question 19

Why is the use of monoclonal antibodies good in cancer treatment?

Answer 19

They target cancer cells only without harming body cells

Question 20

What is a disadvantage of the use of monoclonal antibodies on treatment?

Answer 20

• Monoclonal antibodies create more side effects than expected
• They are not yet as widely used as everyone hoped when they were first developed

Question 21

How are monoclonal antibodies produced?

Answer 21

• Specific antigen is injected into the mouse
• this stimulates the mouse’s B-lymphocytes to produce complementary antibodies, which are extracted
• the lymphocytes are combined with a particular kind of tumour cell to make a hybridoma cell
• the hybridoma cell can both divide and make the antibody
• Single hybridoma cells are cloned to produce many identical cells that all produce the same antibody
• A large amount of the antibody can be collected and purified.

Question 22

what are some of the uses of monoclonal antibodies?

Answer 22

• Pregnancy tests
• Diagnosis of disease
• Treating disease
• Measuring or monitoring
• Research

Question 23

explain three ways monoclonal antibodies can be used to treat cancer

Answer 23

• direct use of monoclonal antibodies to trigger the immune system to recognise, attack, and destroy cancer cells
• using monoclonal antibodies to block receptors on the surface of cancer cells and so stop the cells growing and dividing
• monoclonal antibodies can be used to carry toxic drugs or radioactive substances for radiation therapy, or chemicals that stop cells growing and dividing to attack the cancer cells directly

Question 24

how are monoclonal antibodies used for research?

Answer 24

• research scientists use monoclonal antibodies to locate or identify specific molecules in a cell or tissue
• scientists produce the monoclonal antibodies linked to a molecule of a fluorescent dye
• when the monoclonal antibodies bind to the desired molecules, scientists can see what has happened by observing the build-up of fluorescence