15.9.5 Sexual Reproduction in Flowering Plants (Structured Question 1 & 2)



Question 1:
Diagram below shows a longitudinal section of the reproductive parts of a flower during fertilization.


(a)
On the Diagram, name the structures J, K, L and M.


(b)(i)
In the space below, draw a section through the ovule, showing all the cells in M.
(b)(ii) What is the significance of having two K structures in the fertilization?

(c)
In the Diagram, the structure Y has to be kept dormant for future research purposes.
(i) Explain how Y can be prevented from germinating.
(ii) If Y is to be germinated, suggest one method to stimulate the germination of Y.



Answer:
(a)
J : Pollen tube
K : Male gamete
L : Ovary
M : Embryo sac

(b)(i)



(b)(ii)
– One K/ male gamete fertilizes an egg cell to form a diploid zygote.
– One more K fuses with two polar nuclei to form a triploid zygote.

(c)(i)
– Keep Y in a dry place
– Moisture initiates germination

(c)(ii)
Spraying a sugary solution onto Y



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