FERTILISATION - (PS 15)

Question 1

State the meaning of the term ‘Fertilisation’

Answer 1

Fertilisation is the fusion of the MALE GAMETE FROM THE POLLEN with a FEMALE GAMETE IN THE OVULE to produce a ZYGOTE(embryonic plant - embryo)

GAMETE = sex cell

Question 2

Describe the process of pollination

Answer 2

• pollen lands on stigma
• pollen grain contains 2 nuclei (tube nucleus and generative nucleus)
• tube nucleus forms a pollen tube, the generative nucleus travels down the pollen tube
• on urs way down the tube the generative nucleus divides to form 2 Male gametes
• the Male gametes enter the ovule through the micropyle
• the tube nucleus breaks down
• once inside the ovule 1 Male gamete fuses with the female gamete to produce a ZYGOTE (embryo)
• the 2nd Male gamete fuses with 2 specialised nuclei within the ovule (the polar nuclei) to produce the endosperm (this develops into food store for the developing embryo)
• this is known as double fertilisation and is unique to flowering plants!

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Question 3

What indicates successful fertilisation

Answer 3

If fertilisation has been successful the following will happen:

• sepal and petal /tepals will fall or drop off
• stamen will dry out and drop
• pollen tube will dry out
• stigma and style will dry out and drop off

Only thing left will be Ovary and Ovule