Plant Reproduction - Gametogenesis + Fertilisation

Question 1

Structure of pollen grain

Answer 1

Exine - membrane around pollen
-waterproof = cytoplasm not evaporated by wind

Intine- porous membrane for exchange

Tube nucleus - form pathways in style for generative cell

Generative cell - contain male gametes

Germ pore - hole in extine allow cells to get out

Vacuoles - fill with cell sap to push content into pollen tube

Question 2

Diagram of pollen grain

Answer 2

https://www.vedantu.com/seo/content-images/919f9d99-9272-4f49-ad82-23cf656c23d0.png

Question 3

Males gametogenesis

Answer 3

Mother spore cell -> 4 haploid cell
-via meiosis

1 haploid cell -> 2 types of nuclei (mitosis 1)
-tube nucleus mitosis to also make generative cell

Mitosis 2
-during fertilisation generative cell -> 2 spermatid cell via mitosis

Question 4

Female gametogenesis

Answer 4

Mother cell -> 4 haploid cell
-meiosis
-3 degenerate, only 1 continue to mature

1 nucleus -> 8 nucleus
-egg cell nucleus mitosis via 3 stages
-1 egg cell, 2 polar nuclei

Question 5

Ovule structure

Answer 5

Egg cell - form embryo
Polar nuclei - form endosperm
Integument - membrane of ovule
Micropyle - space for spermatid cell to enter

Question 6

Ovule diagram

Answer 6

https://resource.download.wjec.co.uk/vtc/2020-21/el20-21_1-2/4.2-plant-reproduction-image-9-en.jpg

Question 7

Fertilisation

Answer 7

1)when pollen + stigma chemically compatible, tube nucleus exit, vacuole fill with cell sap to push nuclei

2)tube nucleus drill a pollen tube in style via enzyme to micropyle for pathway for generative cell

3)tube nucleus get to micropyle -> degenerates

4)on the way generative cell mitosis -> 2 spermatid

5)spermatid reach embryo sac via micropyle

6)integumentary harden to form seed shell

Question 8

Double fertilisation

Answer 8

2 types of fertilisation happening

Spermatid + egg cell nucleus = embryo for
-embryo root (radicle)
-embryo shoot (plumule)
-embryo leaf (cotyledons)

Spermatid + 2 polar nuclei = endosperm
-triploid
-nutrient storage for seed

Question 9

Ovary after fertilisation

Answer 9

Integument harden -> seed coat (testa)
ovule harden to become hard seed

Ovary form into fruit wall to encapsulate seed - some may become apple

Question 10

Diagram of seed after fertilisation

Answer 10

https://www.edrawsoft.com/templates/images/seed-diagram.png