Question
During germination and growth of a cereal, the dry weight of endosperm, the embryo and the total dry weight were determined at two day intervals. The results are shown in the table below:
(a) Using the same axes, draw graphs of dry weight of endosperm, embryo and the total dry weight against time.
(b) What was the total dry weight on day 5
(c) Account for
(i) Decrease in dry weight of endosperm from 0 to 10
(ii) Increase in dry weight of embryo from day 0 to day 10
(iii) Decrease in total dry weight from day 0 to day 8
(iv) Increase in total dry weight after day 8
| Time after planting (days) | Dry weight of endosperm (mg) | Dry weight of embryo (mg) | Total dry weight (mg) |
|---|---|---|---|
| 0 | 43 | 2 | 45 |
| 2 | 40 | 2 | 42 |
| 4 | 33 | 7 | 40 |
| 6 | 20 | 17 | 37 |
| 8 | 10 | 25 | 35 |
| 10 | 6 | 33 | 39 |
(a) Using the same axes, draw graphs of dry weight of endosperm, embryo and the total dry weight against time.
(b) What was the total dry weight on day 5
(c) Account for
(i) Decrease in dry weight of endosperm from 0 to 10
(ii) Increase in dry weight of embryo from day 0 to day 10
(iii) Decrease in total dry weight from day 0 to day 8
(iv) Increase in total dry weight after day 8
Answer
(a)
(b) Total dry weight 38.5mg; acc ±0.5
(c) (i) - Hydrolysis of starch into simple sugars/glucose which are translocated to the embryo
- Oxidation/respiration of( simple sugars) to the embryo
- CO2/energy/heat; acc water vapor
(ii) New cells/tissues materials are synthesized (from proteins);bring about growth of embryo
(iii) The rate of respiration is faster than that of synthesis of materials for growth
(iv) First leaf carried out photosynthesis; (leading to growth
(b) Total dry weight 38.5mg; acc ±0.5
(c) (i) - Hydrolysis of starch into simple sugars/glucose which are translocated to the embryo
- Oxidation/respiration of( simple sugars) to the embryo
- CO2/energy/heat; acc water vapor
(ii) New cells/tissues materials are synthesized (from proteins);bring about growth of embryo
(iii) The rate of respiration is faster than that of synthesis of materials for growth
(iv) First leaf carried out photosynthesis; (leading to growth
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