Pollen grains transfer male gametes involved in plant sexual reproduction.
Name the part of the flower where pollen grains land during pollination.
Name the structure through which the male gametes travel to reach the ovary.
Describe how the structure of a wind-pollinated pollen grain differs from an insect-pollinated pollen grain.
A student investigated the germination of pollen grains in a nutrient solution over a period of 150 minutes. The table below shows the percentage of pollen grains that germinated at different times:
| Time (minutes) | Germination (%) |
|---|---|
| 0 | 0 |
| 30 | 20 |
| 60 | 50 |
| 90 | 75 |
| 120 | 85 |
| 150 | 90 |
At a certain time during the experiment, the student observed a sample of pollen grains under a microscope. The diagram below represents the field of view:
Use the diagram and the table to determine the time (in minutes) when these pollen grains were observed. Show your working.
The image diameter of pollen grain P in the diagram is measured as 12 mm. The magnification of the microscope is ×150\times 150×150. Calculate the actual diameter of pollen grain P in millimetres (mm\text{mm}mm). Show your working.
Explain one genetic benefit to a plant of producing seeds via cross-pollination (sexual reproduction) rather than vegetative propagation (asexual reproduction).
