CIE iGCSE Co-Ordinated Science B15.3 Sexual reproduction in plants Exam Style Questions Paper 1
▶️ Answer/Explanation
The style is the stalk-like structure that connects the stigma to the ovary. It is part of the female reproductive organ (carpel/pistil) of the flower. The stigma is the top part that receives pollen, and the ovary is the swollen base containing the ovules.
In the diagram, Part D is the elongated stalk connecting the stigma (Part C) to the ovary (not shown separately). This is the style. Part A is the anther (part of the stamen, producing pollen), Part B is the filament (stalk of the stamen), and Part C is the stigma (the sticky top of the carpel where pollen lands).
✅ Answer: (D)
▶️ Answer/Explanation
After pollination, the pollen grain germinates on the stigma and grows a pollen tube down through the style (the stalk connecting stigma to ovary) to reach the ovule inside the ovary.
The filament supports the anther, petals attract pollinators, and the stamen is the entire male organ — none of these are the channel through which the pollen tube travels.
✅ Answer: (D)
The filament supports the anther, petals attract pollinators, and the stamen is the entire male organ — none of these are the channel through which the pollen tube travels.
✅ Answer: (D)
▶️ Answer/Explanation
Germination requires water to activate enzymes and oxygen for aerobic respiration to release energy.
Light is not a requirement for germination itself, only for the seedling’s later growth by photosynthesis.
The results show seeds germinated whenever water and oxygen were present, regardless of light.
✅ Answer: (C)
Light is not a requirement for germination itself, only for the seedling’s later growth by photosynthesis.
The results show seeds germinated whenever water and oxygen were present, regardless of light.
✅ Answer: (C)
▶️ Answer/Explanation
Fertilisation in a flower is the fusion of the male pollen nucleus with the female nucleus inside the ovule.
This fusion must occur after the pollen tube has grown down the style and reached the ovule.
Diagram B correctly shows this nucleus-to-nucleus fusion taking place inside the ovule.
✅ Answer: (B)
This fusion must occur after the pollen tube has grown down the style and reached the ovule.
Diagram B correctly shows this nucleus-to-nucleus fusion taking place inside the ovule.
✅ Answer: (B)
▶️ Answer/Explanation
The anther is the part of the stamen that produces pollen, and the ovary contains the ovules that develop into seeds after fertilisation.
From the labelled diagram, structure S corresponds to the anther and structure Q corresponds to the ovary.
✅ Answer: (D)
From the labelled diagram, structure S corresponds to the anther and structure Q corresponds to the ovary.
✅ Answer: (D)