repro in plants

Question 1

petal func

Answer 1

• rbightly coloured to attract isects for pollintaion
• provides a platform for insects to land on

Question 2

sepals

Answer 2

• protects floral parts during bud stage

Question 3

anthers func

Answer 3

produce pllen grain contsining male gametes

Question 4

carpel func

Answer 4

• consits of stigma, style, ovary
• stigma receives pollen grains during pollination
  stigma produces sugary liquid for germination of pollen tube
• ovary contains ovules cotaining ovum

Question 5

pollination

Answer 5

trnasfer of pollen graisn from antheer to stigma
mjust occur in order for fusion of nuclei of male gamete and female gamete to take place
effected by wind or insects
cross or self pollination

Question 6

self pollination

Answer 6

transfer of pollen grain from anther to stigma of same flower or flower of same plant

Question 7

cross pollination

Answer 7

trnasfer of pollen grains from anther of one plant to stigma of another plany of the same type

Question 8

clitoria plant/coral tree flower

Answer 8

• insect pollination flower
• bright coorful petals to attract insects and provide platform for their landing
• has nectar guides
• sticky pollen grains that adhere to inscet body
• lower production of pollen graisn bc insecst are a more reliable pollinator than wind
• stamen is positioned such the insecst hairy back will rub against anther and stigma and pollen grains adhere to its back. usually within the corolla of flower
• sticky stigma

Question 9

ischaemum

Answer 9

• wind pollnated flower
• colorless, scentless, no nectar
• small and have bracts that do not interfere with the dispersal of pollen grains
• aundant and small pollen grains
• stamens protrude out of corolla with protruding anthers, sway when wind blows, shaking pollen grains out
• large feathery stigmas that provide large surface area to catch pollen grains

Question 10

insect pollination

Answer 10

• insect (bee) forcs its way bewteen wing petals
• continue its way intoflower to collect nectar at the base of flower
• its back pushes the keel upwards, exposingthe stigma and anthers
• hairy back of insect brushes against anthers and picks up pollen grain
• pollen graisn (from another plant) adhere to the sticky stigma
• pollintaion occurs
• when insect leaves keel springs back to OG position and encloses stigma and anthers

Question 11

growth of the pollen tube and its entry into the ovule followed by fertilisation

Answer 11

• stigma receives the pollen grains
• mature stigma secretes a sugary fluid that stimulates the germination of pollen grains into pollen tube
• pollen tube secretes enzymes as it grows to digest thetissues of style and ovary
• pollen tube grows down the style
• pollen tube enters ovule through micropyle
• tip of pollen tube absorbs sap and bursts to release male gametes
• nuclei of male gamete fuses with nuclei of female gamete to forma zygote (fert)

Question 12

adv of self pollination

Answer 12

• ijcreases chances of
  havign a large number of offsprings
• more reliable

Question 13

disadv of self pollination

Answer 13

• inbreeding, less genetic variation and adaptable to envt

Question 14

cross pollination adv

Answer 14

• more egnetic variety, offspring produced may hv greater genetkc variabiity with valuable qualities from both parnets
• seeds produced are abundant and tend to be more viable, hv genetic variability which increases the chances of survival f the species during envt changes

Question 15

characteristics favouring cross pollination

Answer 15

1. stigmas and antehrs maturing at diff times in a bisexual flower
2. dioecious (where male organs and female organs are on separate plants, papaya )plant where selfing is impossbile
3. ,ehcnaical obstrutions for self pollination
4. self incompatability

Question 16

adv of asexual repro

Answer 16

1. guarantees repro as it has no dependece on others
2. being clones of their parents, they keep the desired characteristics
3. no fragile seed stage, buds havea store of food
4. offspring is as adapted to the envt as the parent
5. faster method of repro

Question 17

disadv of asexual repro

Answer 17

1. little variation to cope with fluctuating envt ( high adaptation but low adaptability)
2. root sprouts - disease spreads from old to young indivials of clones - suscetible to fast spread of epidemics

Question 18

adv of sexual repro

Answer 18

1. hv a diff genetic makeup frm parents - variations
2. means of survvial of the species in unfavourable condtions
3. a good chance for some offsprings to adapt to the new envt

Question 19

commercial adv of asexual repro

Answer 19

1. produce large no. of offsprings
2. offsprings generated quickly
3. all offsprings have known characteristics (flavour, appearance)

Question 20

Suggest, with reasons, the level of genetic variation of offspring from asexual reproduction,
self-pollination and cross-pollination.

Answer 20

• offspring frm asexual repro are egneticlly identical to parents nc it doesnt involve fusion of gametes, only involves mitosis
• offspring from self pollination shows less genetic variety than corss pollintaion
• self polli involves fusion of gametes from one parent
• cross polli involves fusion of gametes of two parnwts