Download 84. Which of the following describes an adjuvant correctly? A An

84. Which of the following describes an adjuvant correctly?
A
B
C
D
An inactivated pathogen
A weakened pathogen
A molecule that inhibits the immune response
A molecule that enhances the immune response
85. Two groups of subjects were used when carrying out clinical trials of a vaccine. One group was given the vaccine
while the other group was given a placebo. The purpose of the placebo was to
A
B
C
D
reduce experimental error
ensure a valid comparison can be made
allow a statistical analysis of the results to be made
ensure that researchers are unaware who has been vaccinated.
86. The diagram below represents clonal selection in lymphocytes
What stimulates the division of cell Y?
A
B
C
D
The presence of lymphocytes X and Z
The presence of an antigen in the blood
The binding of antibodies to receptors on the cell membrane
The binding of antigens to receptors on the cell membrane
87. In which of the following situations might a fetus be at risk from Rhesus antibodies produced by the mother?
88. The graphs below show the effect of two injections of an antigen on the formation of an antibody.
How many days after the second injection does the concentration of antibody in the blood reach the
maximum achieved after the first injection?
A
B
C
D
3 days
6 days
20 days
30 days
89. The immune system protects the body from infection. The table contains information about cells of the immune
system.
(a) Complete the table to identify the cell types and their functions.
2
(i) Explain what is meant by the term active immunity.
1
_______________________________________________________________________________________________
(ii) Describe the role of memory cells in providing long term immunity to a disease.
1
_______________________________________________________________________________________________
(iii) What happens during an autoimmune response?
1
_______________________________________________________________________________________________
Q89 (cont)
The graph shows the number of whooping cough cases over a 65 year period.
(b) (i) Use the graph to determine in which year a vaccine for whooping cough was introduced.
1
Year _______________
(ii) In 1977 newspaper reports suggested that the vaccine was unsafe. This led to a reduction in the number of
children being vaccinated. Calculate the percentage increase in cases of whooping cough between
1977 and 1978.
1
Space for calculation
__________________ %
(iii) The number of cases of whooping cough drops to a very low level after 2000 due to herd immunity. Explain what
is meant by the term “herd immunity”.
2
_______________________________________________________________________________________________
_______________________________________________________________________________________________
90. The diagram below shows how the immune system responds to a polio virus in a vaccine.
(a) Name the type of immunity which results from vaccination with infectious pathogens such as the polio virus. 1
_______________________________________________________________________________________________
(b) (i) Name cell Q.
1
_______________________________________________________________________________________________
(ii) Describe two functions of cell P that are shown in the diagram.
1
1
________________________________________________________________________________________
2
________________________________________________________________________________________
(c) Describe the role of the following cells in combating infection.
2
(i) T-lymphocyte ____________________________________________________________________________
_______________________________________________________________________________________________
(ii) Phagocytes ______________________________________________________________________________
_______________________________________________________________________________________________
(d) Describe the role of memory cells in the immune system.
1
______________________________________________________________________________________________
(e) Explain why vaccination against polio would not provide immunity against the measles virus.
1
_______________________________________________________________________________________________
_______________________________________________________________________________________________
(f) When producing a vaccine an adjuvant is usually mixed with the pathogen. Explain why an adjuvant is added.
1
_______________________________________________________________________________________________
_______________________________________________________________________________________________
(g) Clinical trials of vaccines often use a double-blind protocol. Describe what is meant by the term double-blind.
1
_______________________________________________________________________________________________
_______________________________________________________________________________________________
91. The diagram below shows the structure of one strain of the influenza virus. This virus can be used to prepare a
flu vaccine. In order to do this the nucleic acid must be broken up but the surface proteins left intact.
Explain why it is necessary to:
(i) break up the nucleic acid
1
_______________________________________________________________________________________________
(ii) leave the surface proteins intact
1
_______________________________________________________________________________________________
(b) A different vaccine is required against each strain of the influenza virus. Suggest why different vaccines are
required.
1
_______________________________________________________________________________________________
_______________________________________________________________________________________________
(c) Researchers are attempting to develop a new vaccine which will be effective against all strains of the influenza
virus. Trials of this new vaccine have shown that it increases the activity of T-lymphocytes in the body.
Describe two ways in which T-lymphocytes combat infection.
2
1
________________________________________________________________________________________
________________________________________________________________________________________
2
________________________________________________________________________________________
________________________________________________________________________________________
(d) Clinical trials of vaccines use randomised, placebo-controlled protocols. Describe how these protocols are set up
by the researchers.
2
_______________________________________________________________________________________________
_______________________________________________________________________________________________
_______________________________________________________________________________________________
92. Give an account of infectious diseases under the following headings:
(i)
the classification of the spread of diseases
(ii)
the transmission of disease
(iii)
the control of disease transmission
HOMEWORK 8
TOTAL
40