B6 - Preventing And Treating Disease

Question 1

What can be found inside vaccines

Answer 1

• dead pathogens
• weakened pathogens
• antigens
• toxins
• mRNA mimic

Question 2

What is the MMR vaccine?

Answer 2

Measles Mumps Rubella vaccine

Question 3

define herd immunity

Answer 3

Vaccinated people protect the people who are unable to be vaccinated by acting as a barrier to infections.

Question 4

define antibodies

Answer 4

y-shaped proteins which kill/slow growth of bacteria and fungi.

Question 5

how do antibodies work?

Answer 5

• disrupting cell functions to stop reproduction
• breaking down cell walls

Question 6

why do antibodies not affect viruses?

Answer 6

• viruses are intracellular meaning that antibodies cannot affect them when they are inside human cells.
• viruses don’t have the same cellular structures as bacteria or fungi

Question 7

development of resistance in bacteria

Answer 7

1. random mutations happen in bacteria which produces new strains
2. some strains might gain resistance against antibiotics so they don’t die to antibiotics
3. resistant bacteria reproduce with less competition because other non-resistant bacteria die from the antibiotics.
4. population of the strain rises which is then spread to others
5. there is no effective treatment to kill it off

Question 8

how do vaccines work?

Answer 8

The vaccine stimulates the immune response, leading to memory cell production. If the pathogen re-infects, memory cells produce the correct antibodies that stop the infection. This is called active immunity.

Question 9

define superbug

Answer 9

bacteria or fungi that are resistant to multiple antibiotics

Question 10

give an example of a superbug

Answer 10

MRSA

methicillin resistant staphylococcus aureus

Question 11

how to reduce the rate of development of antibiotic resistant strains

Answer 11

• doctors should not prescribe antibiotics for non-serious or viral infections
• patients should complete the full course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
• agricultural use of antibiotics should be restricted

Question 12

Why is it difficult to keep up with the emergence of new resistant strains?

Answer 12

The development of antibiotics is slow and costly.

Question 13

Why is it difficult to develop drugs that kill viruses?

Answer 13

The drugs can damage human cells.

Question 14

3 examples of drugs extracted from natural sources

Answer 14

• heart drug digitalis - foxglove
• painkiller aspirin - willow
• antibiotic penicillin - Penicillium mould

Question 15

Who discovered penicillin?

Answer 15

Alexander Fleming

Question 16

5 sources of drugs

Answer 16

• plant sources
• microbiological sources
• synthetic sources (starting point may still be extracted from a plant)
• mineral sources
• animal sources

Question 17

What happens in the preclinical development of a drug?

Answer 17

The drug is tested on computer models, human cells, and animals. To test if the drug is safe.

Question 18

What happens in phase 1 clinical development of a drug?

Answer 18

The drug is tested on 50-100 healthy patients. To test if there are any side effects.

Question 19

What happens in phase 2 clinical development of a drug?

Answer 19

The drug is tested on 200-400 infected patients. To test the optimum dose.

Question 20

What happens in phase 3 clinical development of a drug?

Answer 20

The drug, an existing drug, and a placebo are tested on 3000+ infected patients. This is to compare the drug to the existing drug and the placebo to see how effective the new drug is. This phase includes doing blind or dobule blind trials.

Question 21

define blind trial

Answer 21

The patient who takes the drug doesn’t know whether they are given a placebo or the drug.

Question 22

define double-blind trial

Answer 22

Neither the patient who takes the drug nor the doctor who administers it knows whether they are given a placebo or the drug. This method is used to remove bias.

Question 23

define placebo

Answer 23

a treatment with no active ingredient

Question 24

How are monoclonal antibodies produced?

Answer 24

1. antigens are injected into an animal to start an immune response
2. B-lymphocytes, which produce antibodies, are extracted from the animal
3. Myeloma cells, which have a high reproduction rate, are fused with the B-lymphocytes to form hybridoma cells
4. These hybridoma cells have the function of producing antibodies and rapidly reproducing
5. The hybridomas are screened for the production of the desired antibody. These are isolated.
6. The desired hybridomas reproduce and produce antibodies which are then extracted. These are monoclonal antibodies.

myeloma cell - specific tumor cell

Question 25

define monoclonal antibodies

Answer 25

Identical copies of one type of antibody which bind to one specific antigen.

Question 26

2 uses of monoclonal antibodies

Answer 26

• pregnancy tests
• treating cancer

Question 27

How are monoclonal antibodies used in pregnancy tests

Answer 27

Antibodies attached to dyes attach to HCG which is a hormone that is released during pregnancy. After binding with the hormone, the dye is released.

Question 28

How are monoclonal antibodies used to treat cancer?

Answer 28

• binds to cancer and triggers white blood cells to kill them
• disrupts cell activity and stops reproduction
• carry radioactive or toxic substances which kill the cancerous cells

Question 29

How was penicillin discovered?

Answer 29

1. Alexander Flemming noticed that penicillium mould was killing bacteria in a petri dish.
2. Ernst Chain and Howard Florey (from Oxford) took government funding and did research on it in 1940.
3. During WW2 many doses of penicillin were produced.