Chapter 6 - summary questions

Question 1

Vaccination uses your natural defence system to protect you against disease.

Describe how vaccination works
(4 marks)

Answer 1

• small amount of dead or inactive form of disease-causing pathogen introduced into body.
• this stimulating white blood cells to produce antibodies needed to fight pathogen and prevent illness.
• if same, live pathogen is encountered later, immune system can respond rapidly to make correct antibodies
  to destroy pathogen before it can cause illness.

Question 2

Provide a flow chart to summarise the process of developing active immunity after A NATURAL INFECTION
4 marks

Answer 2

 exposure to pathogen
 white blood cells produce antibodies against antigens on pathogen
(whilst you have symptoms of disease)
 antibodies bind to antigens on pathogen
 pathogens inactivated or destroyed
 when exposed to pathogen again memory cells make correct antibodies immediately
 illness prevented

Question 3

Provide a flow chart to summarise the process of developing active immunity after A VACCINATION
4 marks

Answer 3

exposure to weakened or dead pathogen
 white blood cells produce antibodies against antigens on pathogen (without you suffering from disease)
 antibodies bind to vaccine
 pathogens removed
 when exposed to pathogen again memory cells make correct antibodies immediately
 illness prevented

Question 4

There are vaccines for diseases such as diphtheria, polio, tetanus, and meningitis but not for common cold or tonsillitis.
Suggest reasons for this (2 marks)

Answer 4

• Some diseases are so dangerous that death or permanent damage can occur before body has time to develop correct antibodies.
• These are the diseases vaccinated against.
• It is not worth the expense of vaccinating against less serious diseases (eg cold) which are often caused by viruses that mutate very quickly (faster than vaccines can be developed).

Question 5

QUESTION 2

Page 98 Summary Questions

Answer 5

QUESTION 2

Page 98 Summary Questions

Question 6

There are no medicines to cure measles, mumps or rubella. What does this tell you about the pathogens that cause these diseases?

Answer 6

they are viruses

Question 7

Suggest a medicine to make people feel more comfortable when they have measles, mumps or rubella

Answer 7

aspirin or paracetamol

Question 8

Doctors hope to get levels of MMR vaccination against measles, mumps and rubella up to 95% of the population. Why is this important to get vaccination levels so high?
3 marks

Answer 8

• high vaccination levels provide herd immunity

- meaning that enough people are given immunity through vaccination to protect those who are not vaccinated.

Question 9

Explain why new medicines need to be tested and trialled before doctors can use them to treat their patients?
5 marks

Answer 9

 medicine is effective at treating disease
 medicine is safe for patient
 medicine is taken into body effectively
 medicine can be removed from body
 dosage is correct
 medicine is stable

Question 10

Why is the development of a new medicine so expensive?

4 marks

Answer 10

• development and testing of new medicine can take up to 12 years involving multiple stages
• extensive lab resources that make each stage very expensive
• only a small proportion of the thousands of chemicals put through lab trials are eventually put through animal testing,
• an even smaller proportion through human trials

Question 11

Do you think it would ever be acceptable to use a new medicine before all the trials are completed? Explain why?
5 marks

Answer 11

example answers for yes:
 if drug seems so good during trials that it would be unethical not to treat with it
 if need for drug to be used on individual patient as only chance of avoiding death is very clear example

answers for no:
 unethical to use drugs that have not been fully tested
 outcomes such as those associated with Thalidomide are to be avoided.

Question 12

Some people argue for the conservation of biodiversity because the living world is a potential source of new medicine.
Explain why this argument isn’t completely accurate

Answer 12

-traditionally many medicines were developed from plants animals
-some medicines still begin as molecules from plants
however, synthetic chemistry in which molecules are designed for specific effect is now a source of many potential drug molecules so medicine not entirely dependent on biodiversity

Question 13

Describe the importance of herb immunity in the elimination of an infectious disease in a population of people.

Answer 13

• in herd immunity a large proportion of the population is vaccinated against a disease and therefore immune to a disease as a result.
• the spread of pathogen in the population is much reduced. If enough people are vaccinated the disease may even disappear as there is nowhere for the pathogen to survive
• if the number of people taking up a vaccine falls, the herd immunity is lost and the disease can reappear

Question 14

Describe the main steps in the development of a new medicine to the point where it can be used by your local GP or hospital

Answer 14

identify pathway in disease that needs cure
→ identify new chemical (in living organisms or lab)
→ preclinical testing on cells, tissues, and animals
→ phase 1 clinical trials check for side effects
→ phase 2 clinical trials check efficacy and safety
→ phase 3 clinical trials check efficacy, safety, and dosage → licencing
→ phase 4 clinical trials monitor safety throughout life of drug