Lesson eLearning

Describe the process of fertilisation in flowering plants, starting from pollination to formation of the zygote. Include the role of the pollen tube.

medium 4 marks Class 10 · Science · How do Organisms Reproduce
Answer
Pollination brings pollen to the stigma; pollen germinates forming a tube that grows down the style to the ovary, the tube delivers two sperm cells to the embryo sac where one fuses with the egg cell forming a diploid zygote and the other fuses with the central cell forming the endosperm.

Step-by-step solution

  1. State that pollination transfers pollen grains from anther to stigma of a compatible flower.
  2. Explain that on the stigma a pollen grain absorbs water, germinates and produces a pollen tube.
  3. Describe the growth of the pollen tube down the style toward the ovary guided by chemical signals.
  4. Mention that the tube reaches the embryo sac and releases two sperm cells.
  5. Detail double fertilisation: one sperm fuses with the egg cell to form a diploid zygote, the other fuses with the central cell to form triploid endosperm.
  6. Summarise the whole sequence as the answer.
Common mistake: Omitting the pollen tube or the double fertilisation step

Concept tested: Fertilisation in angiosperms

Published · Last updated · How this solution was prepared and checked

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