1.
C
2.
D
3.
A
4.
B
5.
C
6.
B
7.
C
8.
C
9.
C
10.
B
11.
a. an organism or a virus that causes a disease
1
b)
1. antibiotics block/inhibit specific metabolic pathways/
cell functions found in bacteria;
Accept specific examples of inhibition such as cell protein synthesis
cell wall
formation
2. viruses must use host/eukaryotic cell metabolism / viruses do not
have their own
metabolic pathways;
3. host/eukaryotic cell metabolism/pathways not blocked/inhibited by
antibiotics; 2 max
[5
12.
(a)
1. active immunity is by the production of antibodies by the body and
passive immunity is when
antibodies are obtained from an external source;
2. in active immunity the individual is exposed to the antigen/pathogen/
has the disease and in
passive immunity the individual is not exposed;
3. active immunity gives rise to memory cells and passive immunity does not;
2 max
(b)
1. B lymphocytes are produced in laboratory animal after injection with an
antigen which
induces a specific antibodies;
2. animal cells/these cells are fused with tumour cells (to form hybridomas
which) produce
antibodies;
2
(c)
1. HIV virus transmitted by body secretions/semen/blood/across placenta;
2. transmitted by infected blood transfusions/intravenous drug users;
3. mainly by sexual activity/promiscuity;
2 max
13.
1. (c)vaccine is a modified/weakened/attenuated form of a pathogen /
contains antigens
from pathogens;
2. vaccine injected/ingested/introduced to patient;
3. pathogen/antigens stimulates specific immune response called
primary/initial
responses;
4. antigens stimulate macrophages/lymphocytes/T-cells;
5. macrophages/lymphocytes/T-cells stimulate cloning of B-cells/plasma cells;
6. Stimulate B-cells will divide via mitosis and some will become memory (B-)cells;
7. B-cells are made that produce specific antibodies;
8. Upon second exposure to the same antigen the production of antibodies is much
faster;
9. higher level of antibody production results in a person having an immunity to disease;
10. This faster antibody production during a secondary exposure is called secondary
response;
11. Labelled graph showing curve with higher slope/peak for secondary
response than
primary response (BOTH AXIS must be Labelled);
12. Some vaccines may need booster shot to maintain immunity;
13. Vaccines is an example of active artificial immunity;
9 max
14(b)
1. cells/tissue is damaged/cut/bruised;
2. damaged cells/platelets release clotting factors;
3. (clotting factors cause the) production of thrombin;
4. blood plasma contains soluble fibrinogen;
5. fibrinogen converted into fibrin;
6. fibrinogen converted into fibrin by thrombin;
7. forms a net of fibres from fibrin trapcc blood cells;
8. forming a clot / prevents blood loss / entry of bacteria/pathogens;
9. cascade of reactions/series of stages prevent accidental clotting/
speed up clotting;
(a) 11.4% (accept answer in the range of 11.2% and 11.6%)
1
(b)
1. Both lipids/LCT and LCT-MCT increase the percentage of neutrophils
secreting
H2O2;
2. LCT causes greater increase than LCT-MCT;
3. Both lipids increase the percentage more at the higher concentration;
4. Higher concentration increases effect of LCT more than LCT-MCT;
5. Both (lipid solutions) have highest values at end of the incubation
period; 3 max
(c)
lipids are hydrophobic/insoluble so form droplets/coalesce/cause blockages
1
(d)
1. 0.06 mg cm–3 concentration / LCT-MCT treatment is best/safest;
2. supplies lipids;
3. avoids high/harmful hydrogen peroxide levels / percentages;
4. LCT at 0.6 mg cm–3/higher level causes high/increasing hydrogen peroxide;
5. danger of side effects from hydrogen peroxide;
6. conclusions uncertain due to lack of data / example of unavailable
information;3 max
[8]