Question 1 Report
(a) (i) Explain the term agglutination as used in blood transfusion.
(ii) The table below represents blood transfusion between blood donors and recipients.
| Donor | Recipient | ||||
| A | B | AB | O | ||
| A | |||||
| B | |||||
| AB | |||||
| O | + | ||||
(b) Explain how each of the following organisms are adapted for obtaining food.
(i) Mosquito larva
(ii) Dodder plant
(iii) Grasshopper
(a)(i) Agglutination
Agglutination is the clumping together of red blood cells that occurs when incompatible bloods are mixed during transfusion. It is caused by a reaction between the antigens on the donor's red cells and the corresponding antibodies in the recipient's plasma.
(a)(ii) Blood transfusion compatibility
A tick means the transfusion is safe (no agglutination); a cross means agglutination occurs.
| Donor \ Recipient | A | B | AB | O |
|---|---|---|---|---|
| A | Yes | No | Yes | No |
| B | No | Yes | Yes | No |
| AB | No | No | Yes | No |
| O | Yes | Yes | Yes | Yes |
Group O is the universal donor (can give blood to all groups) and group AB is the universal recipient (can receive from all groups).
(b) Adaptations for obtaining food
(i) Mosquito larva: it has a breathing siphon so it can hang at the water surface, and tufts of mouth brushes that beat to create currents which sweep tiny food particles and micro-organisms in the water into its mouth (filter feeding).
(ii) Dodder plant: it is a parasite with no chlorophyll; it twines around a host plant and develops haustoria (suckers) that penetrate the host's tissues to absorb ready-made food and water.
(iii) Grasshopper: it has strong biting and chewing mouthparts (hard mandibles and maxillae) that cut and grind plant material, suiting its herbivorous diet.
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