Question 4
(a) (i) Explain the term agglutination as used in blood transfusion. [3 marks]
(ii) The table below represents blood transfusion between blood donors and recipients. Copy and complete the table using the keys (+) to represent compatibility and (-) to represent incompatibility.
Recipient |
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Donor |
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A |
B |
AB |
O |
A |
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B |
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AB |
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O |
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[7 marks]
(b) Explain how each of the following organisms are adapted for obtaining food:
(i) Mosquito larva;
(ii) Dodder plant;
(iii) Grasshopper. [10 marks]
Observation
Very few candidates attempted this question and most were not able to define the term ‘agglutination’. However, some candidates wrote clumping of blood or wrong blood.
The candidates that attempted (a)(ii) did it satisfactorily.
Majority of candidates answered (b) poorly. Many candidates could not write the structures that adapt the organisms to their feeding.
The expected answers are:
(a) (i) Agglutination
The clumping together; of antigens of red blood cells/RBC; with the corresponding
antibodies in the plasma; of incompatible blood groups/wrong blood group.
(ii) Table
Donor |
|
Recipient |
|||
A |
B |
AB |
O |
||
A |
+ |
- |
+ |
- |
|
B |
- |
+ |
+ |
- |
|
AB |
- |
- |
+ |
|
|
O |
+ |
+ |
+ |
+ |
|
(b) How each of the following organisms are adapted for obtaining food
(i) Mosquito larva
- - Possess a pair of ciliated mouth brushes; for creating water current to carry
water with food particle into the mouth;
- Its mouth brushes; filter food out of water and sweep it into the mouth.
(ii) Dodder plant
- - Possess haustoria; for penetrating host plant tissue to obtain food/water.
(iii) Grasshopper
- - Possess mandibles/heavy toothed jaw-like structures; for cutting/crushing
food/plant materials/vegetation;
- - Possess maxillae; for directing food to mandibles/cutting/grinding food;
- - Labrum; for holding food/plant materials/vegetation;
- - Labium; for guiding foods/prevent it from falling off.