1. 1
   A student examines an insect-pollinated flower and records the structures involved: sepals protecting the bud, brightly coloured petals, stamens (each with a filament and anther) producing pollen, and a carpel with a sticky stigma, style, ovary and ovules.

   (a)

   A student examines an insect-pollinated flower and notes that a sticky structure at the top of the carpel receives pollen grains carried by visiting insects. What is this structure called?

   [1 mark]

   • AThe anther
   • BThe stigma
   • CThe filament
   • DThe sepal

   (b)

   Pollen grains are produced on the stamen of the flower. Which part of the stamen produces the pollen grains?

   [1 mark]

   • AThe filament
   • BThe style
   • CThe anther
   • DThe ovary

   (c)

   State the functions of the petals and the ovules in this insect-pollinated flower.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A bee visits a flower to collect nectar and, in doing so, transfers pollen grains from the anther of that flower to the stigma of a different flower on a nearby plant of the same species. A pollen grain then germinates and grows a pollen tube down through the style.

   (a)

   A bee visits a flower and, while collecting nectar, transfers pollen from the anther of that flower to the stigma of a different flower on the same species growing nearby. What is this process called?

   [1 mark]

   • ACross-pollination
   • BSelf-pollination
   • CFertilisation
   • DGermination

   (b)

   After pollination, a pollen grain on the stigma produces a pollen tube that grows down through the style towards the ovary. What is the main function of the pollen tube?

   [1 mark]

   • ATo attract more pollinating insects to the flower
   • BTo protect the flower bud before it opens
   • CTo produce nectar for pollinators
   • DTo carry the pollen nucleus down to an ovule so that fertilisation can occur

   (c)

   Describe what happens after the pollen tube reaches an ovule, leading to fertilisation.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A botanist compares an insect-pollinated flower with a wind-pollinated grass flower that has small, dull petals, large feathery stigmas hanging outside the flower, and anthers that hang loosely on long filaments outside the flower, and also examines the differences between the pollen grains produced by each type of flower.

   (a)

   A botanist compares a wind-pollinated grass flower with the insect-pollinated flower described earlier. The grass flower has small, dull-coloured petals, large feathery stigmas that hang outside the flower, and anthers that hang loosely on long filaments outside the flower. Explain how the structure of the anthers and stigma of the wind-pollinated flower are adapted for pollination by wind.

   [3 marks]

   (b)

   The botanist also compares the pollen grains produced by the insect-pollinated flower with those produced by the wind-pollinated grass flower. Describe how the pollen grains of insect-pollinated and wind-pollinated flowers typically differ, and explain why the wind-pollinated flower produces far more pollen grains than the insect-pollinated flower.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A gardener plants seeds from the same packet in two locations: moist soil in a warm greenhouse, where they germinate successfully, and a sealed, dry, cold container, where they fail to germinate. The gardener also wants to understand why cross-pollination, rather than self-pollination, might benefit the resulting plants.

   (a)

   A gardener notices that seeds from a packet germinate successfully when planted in moist soil in a warm greenhouse, but identical seeds left in a sealed, dry, cold container do not germinate at all. Explain, with reference to the environmental conditions required for germination, why the seeds in the greenhouse germinated but those in the sealed container did not.

   [6 marks]

   (b)

   The gardener also wonders whether it is better for the flowering plants in the garden to rely on self-pollination or cross-pollination. Discuss the potential effects of self-pollination and cross-pollination on a population of plants, in terms of genetic variation and the plants' ability to respond to environmental change.

   [6 marks]

   Total for question 4: 12 marks

End of questions