09 Sb Tys Unit 10.1

4/15/09

Structured Qn 1a Reproduction in Plants Sci Bio TYS Unit 10.1a Structured Questions 1-5

 i) A: Name-Ovary Function-To produce ovum(female gamete).

 ii) B: Name- Petal Function- To attract insects to pollinate the flower. - Landing platform for insects

 iiii) C: Name-Stamen Function- To produce pollen grains.

Structured Qn 1b&c

Structured Qn 2

b) 1.Cross pollination by insects/animals 2. Self pollination c) A pollen tube germinates from the pollen grain when stimulated by the sugary fluid secreted by the mature stigma. Enzymes are secreted to digest the tissues of the stigma & style as the pollen tube penetrates through it and enters the ovule through the micropyle. The male gametes in the pollen pass into the pollen tube and reach the ovule in this way.

 1.Asexual reproduction does not involve the formation or fusion of male and female gametes whereas sexual reproduction does.

 2. Asexual reproduction produces genetically identical offspring whereas sexual reproduction produces offspring with variation.

Structured Qn 3

Structured Qn 4

  a) Pollination is the transfer of pollen grains from the anther to the stigma. There exists 2 types. Self pollination occurs when the pollen grains are transferred to the stigma of the same flower or a different flower in the same plant. If the pollen grains are transferred to a flower in another plant of the same kind, it is called crosspollination instead.

 b) Fertilisation is the fusion of two dissimilar sexual reproductive units, the male and female gametes.

 a) Sexual reproduction is the production of a new individual that involves fertilization, fusion of gametes.

 b) Sexual reproduction involves 2 parents whereas Asexual reproduction involves 1.

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4/15/09

Structured Qn 5a & b

 A: Petal

 B: Stamen

 C: Sepal

Structured Qn 5c

 i) To prevent self-pollination/ To ensure cross-pollination.

 ii) Offspring of cross-pollination possess valuable qualities from both parents thus enabling them to be much healthier and are better adapted to environmental changes. (more variation) Also more abundant & more viable seeds tend to be produced by cross-pollination.

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