B6 - Preventing and Treating Disease

Question 1

What are antibiotics?

Answer 1

Antibiotics are chemicals that damage bacteria and eventually kill them. Each types of antibiotic interferes with the bacteria’s life processes, e.g. making a cell wall.

Question 2

What are antibiotics?

Answer 2

Antibiotics are chemicals that damage bacteria and eventually kill them. Each types of antibiotic interferes with the bacteria’s life processes, e.g. making a cell wall.

Question 3

Can antibiotics kill viruses?

Answer 3

No. They do not kill viruses, protozoa or fungi.

Question 4

Name a common antibiotic

Answer 4

Penicillin

Question 5

What is meant by antibiotic efficacy?

Answer 5

Antibiotic efficacy is how effective an antibiotic is at killing a certain type of bacteria.

Question 6

Explain the stages how bacteria can become resistant to antibiotics.

Answer 6

1. Antibiotics kill individual bacterial pathogens of the non-resistant strain. 2. Resistant/mutated pathogens survive and reproduce. 3. The population of the resistant strain of pathogens increases because they are not affected/killed by the antibiotic. 4. The resistant strain will then spread because people are not immune to it and there is no effective treatment.

Question 7

How should antibiotics be prescribed and taken?

Answer 7

• Only by a doctor after a consultation - Should not be prescribed for mild infections. - Should not be prescribed for viral infections. - Make sure the patient finishes the full course

Question 8

Which type of blood cells fight disease?

Answer 8

White blood cells

Question 9

Name the type of white blood cell that engulfs pathogens

Answer 9

Phagocyte

Question 10

Name the type of white blood cell that produces antibodies

Answer 10

Lymphocyte

Question 11

Why do antibiotics not kill virsues?

Answer 11

Antibiotics work by disrupting the bacterial cell structures e.g. cell wall. Viruses replicate INSIDE cells so antibiotics can not kill them.

Question 12

When you get a vaccination what does the doctor actually inject you with?

Answer 12

A weakened/dead form of the pathogen that still retains the antigens (receptors).

Question 13

What is an antigen?

Answer 13

All cells (including human body cells) have receptors on their surface. These are called antigens.

Question 14

Define herd immunity.

Answer 14

Herd immunity involves vaccinating a large proportion of the population against a certain pathogen (e.g. flu vaccine). This is to reduce the number of people getting the disease and therefore it reduces the spread of the disease.

Question 15

Where did the heart drug digitalis originate from?

Answer 15

It originated from the plant - foxgloves.

Question 16

From what plant does the painkiller aspirin originate from?

Answer 16

The painkiller aspirin originates from willow.

Question 17

From which microorganism does the antibiotic penicillin originate?

Answer 17

Penicillin was discovered by Alexander Fleming from the Penicillium mould.

Question 18

Why do new drugs have to be tested before use?

Answer 18

To ensure….. • They are safe • Do not have any toxic side effects • The correct dose is given • They are stable

Question 19

What are the 4 stages of drug testing?

Answer 19

1) Pre-clinical trials 2) Phase 1 clinical trials 3) Phase 2 clinical trials 4) Phase 3 clinical trials

Question 20

In a pre-clinical trial what are the drugs tested on?

Answer 20

Pre-clinical trials: this is where drugs are tested on cells, tissues and live animals e.g. mice. This is to ensure there are no unwanted side effects.

Question 21

In a clinical trial what are drugs tested on?

Answer 21

Clinical trials: this is where the drug is tested on humans.

Question 22

What is a double blind trial

Answer 22

This is a drugs trial where some patients receive the active drugs and some patients receive the placebo. Neither the patient nor the doctors knows who has received which treatment.

Question 23

What is a placebo?

Answer 23

A placebo is a substance that does not contain the active drug. It has no therapeutic effect but may have a psychological affect. A placebo is used as a control in testing new drugs.

Question 24

In phase 1 clinical trials, who is the drug tested on?

Answer 24

Phase 1: drug is tested on healthy volunteers. Low doses are used. This is to test for any adverse side effects and toxicity

Question 25

In phase 2 clinical trials, who is the drug tested on?

Answer 25

Phase 2: drug is tested on a small number of people who actually have the disease (i.e. patients). A double blind trial is used. This is to test for the optimum dose, and to test for the efficacy (Whether it works)

Question 26

In phase 3 clinical trials, who is the drug tested on?

Answer 26

Phase 3: larger numbers of patients are used. Patients are given the drug or placebo. This is to verify the efficacy/effectiveness of the drug and to determine the correct dose.

Question 27

Why is it difficult for Scientists to develop drugs that kill viruses?

Answer 27

It is difficult to develop drugs that kill viruses as viruses reproduce inside cells. Therefore it is difficult to just kill the virus and not the body’s tissues too.

Question 28

Explain how a person develops immunity to a certain disease after receiving a vaccination.

Answer 28

• A dead/weakened/inactive pathogen is injected into the patient’s bloodstream. The pathogen still retains the antigens.
• Specific lymphocyte recognises the specific antigens and 1) produces clones of itself and 2) produce large amounts of the correct antibody.
• Pathogen is killed by the antibodies.
• ‘Memory lymphocytes’ remain in the bloodstream.
• This provides immunity to that specific pathogen.
• If the same pathogen re-enters the body the white blood cells respond (more) quickly to produce large amounts of the correct antibodies, preventing infection.

Question 29

How is a monoclonal antibody made?

Answer 29

Lymphocytes make antibodies but cannot divide. Tumour cells do not make antibodies but can divide rapidly to make a clone of cells. Scientists combine mice lymphocytes with a tumour cell to create a hybridoma cell. The hybridoma cell divides to make a large number of identical clones that all produce the same antibody. These antibodies are collected and purified. They are monoclonal antibodies - antibodies produces from a single clone of cells

Question 30

What is a monoclonal antibody?

Answer 30

•Monoclonal antibodies are produced from a single clone of cells, consisting of identical antibody molecules.

Question 31

How do monoclonal antibodies work?

Answer 31

The antibodies are specific to one binding site on one particular antigen and so are able to target a specific chemical or specific cells in the body.

Question 32

When a B lymphocyte fuses with a tumour cell, what is the resulting cell formed called?

Answer 32

A hybridoma cell

Question 33

Name a use for monoclonal antibodies in medicine.

Answer 33

• Pregnancy tests
• Diagnosis of disease
• Measuring and monitoring levels of hormones/other chemicals in the blood

Question 34

Monoclonal antibodies are present in pregnancy testing kits. How do monoclonal antibodies indicate pregnancy?

Answer 34

• The blood of pregnant women contains a hormone called hCG that is made early in pregnancy.
• Tiny amounts of this hormone are passed out of the body in the urine.
• Monoclonal antibodies in the pregnancy test bind to the HCG hormone if it is present.
• This produces a colour change and positive result.

Question 35

Name some possible side effects of monoclonal antibodies.

Answer 35

• Fever
• Chills
• Vomiting
• Nausea

Question 36

What are hybridomas?

Answer 36

cells created during the production of monoclonal antibodies by the fusion of an antibody-specific lymphocyte and a tumour cell

Question 37

What is a vaccine?

Answer 37

dead or inactive pathogenic material used in vaccination to develop immunity to a disease in a healthy person

Question 38

Describe how “cadida albicans” Monoclonal Antibodies and a fluorescent dye could be used to see if there are any “cadida albicans” on a slide:

Answer 38

The monoclonal antibodies should first bind with the fluorescent dye. The fluorescent mAbs should then be placed on the slide. If “cadida albicans” is present, the monoclonal antibodies would bind to the antigens on the pathogen. This would then be able to be viewed under a microscope to see if there are any pathogens present.

Question 39

Suggest 1 reason why mAbs made using human lymphocytes are more successful in treating diseases in humans than mAbs made using mice lymphocytes:

Answer 39

The body is less likely to reject the mAbs made from human lymphocytes, whereas it is more likely to reject the mAbs made from mice lymphocytes