This document provides information about sexual reproduction in flowering plants. It discusses the structures and functions of flower parts, the processes of pollen grain and embryo sac formation, pollination, fertilization, seed formation and dispersal. Key points covered include the male and female reproductive organs in flowers, meiosis in pollen and embryo sac development, the importance of double fertilization, and how seeds enable plant survival and reproduction.

1. Chapter 6: Sexual Reproduction
in Flowering Plants
Name : Thanhya Phrassanna Naidu Puspakaran
Class : 5 Diamond
Class Teacher : Pn. Zawiyah bt. Othman

2. Formative Practice 6.1
1. The diagrambelow shows thestructureof aflower.
(a)Label partsA - F.
(b)Statethefunction of partsA - F.
A: anther
B:petal
C:filament
D:stigma
E :ovary
F:sepal

3. (b)A :Haspollen sacswhichcontain pollen grains(microspores)
B:Attractsinsectsandanimals
C:Stalk thatholds up theanther
D:Place wherepollination occurs
E :Female reproductive organ
F:Protectstheflower atbud stage.
2.Whyarestamensandcarpels knownasthereproductive organs of flowering plants?
Antherproduces malegametes(pollen grains)while carpel producesembryo sac.
3.Compare maleandfemale reproductive organs of flowers intermsof their:
(a) Names
(b) (b)Structuresthatform them
(c) (c)Functions

4. (c)

5. Formative Practice 6.2
1. Namethecell thatdifferentiates toform:
(a)Pollen grainsin theanther
(b) Embryo sacintheovary
(a) Microsphore mothercell
(b) (b)Megaspore mothercell
2.In theformation of pollen grains,thenucleusinthepollen will dividebymitosis toform two
nuclei. Justify.
Produces two nuclei, namelythegenerativenucleusandthetubenucleus.The tubenucleus
forms pollen tubewhereasthegenerativenucleusdivides mitotically inthepollen tubeto form
twomalegametes.
3.Whatistheimportance of meiosisin theformation of pollen grainsandcellsof theembryo
sac?

6. Produces gameteswhicharehaploid
4.After theformation of embryosaciscompleted, thiscellcontains eightnuclei.Namethe
nuclei.
3antipodal cells, 2polar nuclei, 1eggcell, 2synergidcells.

7. Formative Practice 6.3
1. Whatismeantby pollination?
Thetransfer of pollen grains from theanthertothestigma
2.Pollination isveryimportantto ensurethatreproduction inflowering plants occurs successfully.
Explain.
Pollination transfers pollen grains from anthertostigma.Thepresenceof pollen grains on thestigma
initiatesthefertilisation.
3. Duringtheformationof pollen grain, themicrospore mothercell divides bymeiosisandproduces
tetrad.Statethefeatures ofthetetradand theimportanceof suchfeatures.
Tetradcells arehaploid tomaintainthenumberofchromosomes inthezygote after fertilisation.
4.Thegenerativenucleus dividesbymitosisinthepollen tube.Statetheimportanceof thisprocess.
Produces twonuclei,namelythetubenucleus thatwillform thepollen tubeandthegenerativenucleus
thatwillform themalegametes.

8. 5.The megasporecellcontains eightnuclei.Howdoes thisoccur?
The nucleusof megasporemother cell withundergo mitosisthreetimesto produceeight nuclei.
6.Statetherole ofdouble fertilisation inensuringthesurvivalof flowering plants.
The fertilisation of maleandfemale gametesproducesadiploid zygoteandtransmitsgenetic
information tothenextgeneration. The fusion of thesecond malegametewiththepolar nucleito
form atriploid endospermnucleus thatwill develop intotheendospermtissue.Thistissuesupplies
food for seedgermination.

9. Formative Practice 6.4
1. After fertilisation occursbetweenthemalegameteandtheeggcell,thezygoteproduced
undergoesmitosis forming two cells. Explain.
Onecellwill develop toform thesuspensorandanothercell will develop toform theembryo.
2.Statethestructureof theseedwhichenables ittobestoredfor along timebefore itgerminates.
Testa
3.Whatisthefunction of thesuspensorin thedevelopmentof seeds?
Anchors theembryoto thewall oftheembryo sac
4.What isthedifference betweentheplumule andradicle whicharestructuresforming anembryo
inaseed?
Plumule grows up to form theshoot while radicle grows down toform theroot

10. 5.The exocarpis saidtoprotectfruitsfrom spoiling. Justify.
Exocarp isastrong andwaterproof skin.Itprotects fruit from waterloss andfungal attack

11. Formative Practice 6.5
1. Whyareseedsimportant to ensurethatplant speciesarenot extinct?
Seedscontainembryosthatwill germinatetoform newplants
2.Explain thefollowing statements.
(a) There are cotyledons inside aseed
(b) (b)Some plantshaveaverylarge numberof seeds
(a)Cotyledons supplyfood toseedlings before thepresenceof leavesfor photosynthesis.
(b)Increasethechancesfor seedgerminationtoensurethesurvivaloftheplantspecies.
3.Whydoesasexual reproduction produce cropsof lesserquality comparedtosexualreproduction
throughseeds?
Asexualreproduction producescropsthathavethesamefeatures astheparent,i.e. identical and
thereisnoadditional betterfeature Q.Sexualreproduction producesplants thatinheritfeatures
from twotreesthatproduce seedlingswhich arenot identical andof betterquality

12. Summative Practice 6
1. The stigmasecretesasugarysolution called nectar.Whatistheimportance ofthe
solution?
Stimulate thegerminationof thepollen grainsto form pollen tube.Makesthestigmasticky
andallows thepollen graintosticktoit.
2.The formation ofpollen grains involves thedivision of cellsbymeiosis andmitosis.Statethe
importance ofboth processes.
Meiosis –Produces haploid gametecells
Mitosis –Increasesthenumberof nucleusto develop into pollen grains
3.In somespecies,thepetalsarenot included inthereproductive structureof theflower, but
theyareveryimportantinensuring thatreproduction occurs.Why?
The colour of thepetalscanattractpollinating agents

13. 4.Flower Xispollinated byinsects.Statetheposition of theantherandstigmaoftheflower.
Explain your answer.
Located inside thepetals.This ensurestheinsectsthatentertheflower for nectarwill come
intocontact withpollen grains andtransfer themtothestigma.
5.Lalang producesdull-coloured flowers without nectar.However, itisveryeasyfor thisplant
toreproduce. Explain.
Lalang hasmanypollen grainswhich arelight.This feature enable thepollen grainsareeasily
dispersedbythewind.
6.Mr.Sureshisafarmer whogrows long beans.Mr. Sureshoften letsthefruits from someof
thetreestomatureanddries themtomakeseeds.Suggestone wayto storetheseedsso that
theylastlonger.

14. Stored inanairtight container andwiththeabsenceof water.The seedscannot germinate
without air andwater. This enablesseedstobestored for along time
7.Atreehasproduced twoflowers. However, thetreewasattackedbyatypeof fungus that
damagedthestructureof itsstigma.Thishasdisruptedthedivision of thegenerativenucleus
inthestyle. Inyour opinion, canthistreeproduce fruits andseeds?Explain.
No. There isnogermination ofthepollen grainonthestigma,noformation ofpollen tube
8.Figure 1showstheconversationbetweenSalina andLiza.

15. Doyou supporttheopinion of Salina orLiza? Explain.
Liza.
-Coniferous trees/gymnospermsdo not haveflower buthaveseedsproducedbythecone.

16. Thank You Everyone!