A species of flowering plant has flowers of two types. Some of the plants of this species have flowers called pin and some of the plants have flowers called thrum. The diagrams show sections through parts of these two types of flower. [Figure showing pin flower and thrum flower]

1. (a)Describe how the structure of the pin type of flower differs from that of the thrum type of flower.[3]
2. (b)Pollination in this species of plant is not always successful in leading to fertilisation. Examples of successful pollination and of unsuccessful pollination are shown in the diagram below. [Figure showing pollination paths] Use information from the diagram to name the type of pollination that is successful and suggest the advantage to the species of this type of pollination.[3]
3. (c)(i)The gene responsible for the production of the different types of flower has two alleles. One allele (T) is dominant to the other allele (t). A plant with flowers of the pin type has a homozygous recessive genotype. A plant with flowers of the thrum type has a heterozygous genotype. Use the letters T and t to show the genotype of each of the following: a plant with flowers of the pin type a plant with flowers of the thrum type[2]
4. (c)(ii)A plant with flowers of the pin type was successfully pollinated by a plant with flowers of the thrum type. Complete the genetic diagram shown below and state the likely ratio of new plants being produced with flowers of the pin and thrum types. [Figure of Punnett square] ratio of new plants with flowers of the pin and thrum types:[3]

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